NATIONAL LIBRARY OF MEDICINE Bethesda, Maryland Gift of The New York Academy of Medicine A/\ Vol. No._ ^SENTED S/^6. The New Y of Medicine By 1. ^-i&_s 79 / 7^y $?. cZ.-<&M-Czt- ^7-7 ^c &*r?^4u£^ "" 7& / i ■ C H H > < > > I-1 ANALYSIS OF DOLOMITE. 31 Note 2.—If it is desirable to determine the Si02 in the silicates present, " Residue a" must be treated as follows : Dry and ignite (with filter), mix in a platinum crucible with about six parts of Na2C03 (anhydrous), and fuse at a red heat. Cool, remove the fused mass with boiling water, add an excess of HCl, evaporate to dryness on a water-bath, heat in an air-bath until the HCl is completely expelled ; again moisten with HCl, dissolve in water, and filter from the residue. The residue which is now pure hydrated SiO_„ is dried, ignited, and weighed. The filtrate must be added to "Filtrate a!' Examine Fres., § 140, II, b,a, and § 93, 9. Note 3.—Heat the filtrate from " Residue a" add NH4C1, and NH4HO in slight excess. (The NH4C1 may be omit- ted if the " Filtrate a " is very acid.) Heat until excess of NH4HO is expelled, filter quickly, and wash hot. See Fres., § 113, 1, a, and § 105, 1, a. Note 4.—" Precipitate b " is partly washed, and then, while moist, dissolved in a little warm dilute HCl on the filter, the solution is reprecipitated by NH4HO and the precipitate brought on the same filter, washed thoroughly, dried, and ignited. Weigh as Fe203-(-Al203. The second filtrate is added to " Filtrate b." Note 5.—Concentrate '■' Filtrate b" add some NH4C1 un- less present already, add (NH4)2 C204 in considerable ex- cess, and some NH4HO. Let stand 12 hours in a warm place. Wash partially and filter. See Fres., § 154, 6, a ; also § 103, 2, b, a. Note 6.—Dissolve the partially washed " Precipitate c" in HCl, reprecipitate with NH4HO and a little (NH4)2C204. Filter and wash hot, add filtrate and washings to " Filtrate c." Dry precipitate on funnel, transfer to crucible, burn fil- ter, add ashes, add a few drops of cone. H2S04 to contents of 32 QUANTITATIVE ANALYSIS. crucible, ignite cautiously to low redness, and weigh as CaS04. Compare Fres., § 103, 2, b, «. Note 7.—If care has been taken to avoid undue excess of NH4C1 in the preceding steps, the magnesium may be thrown down in " Filtrate c " immediately. Otherwise the NH4C1 must be expelled as follows : Concentrate the liquid, add 3 grms. of HN03 for every grm. of NH4C1 supposed to be in the solution, warm gently (6o° C.) and eventually heat to boiling. Concentrate " Filtrate c" add NH4HO and Na2HP04 and proceed as in Analysis 2. B. See Fres., § 104, 2, and § 74- Notes on the Decomposition of NH4C1 by HN03 in solu- tion. Comptes Rendus, October 13, 1851 (Maumene). J. Lawrence Smith in American Chemist, Vol. Ill, p. 201. Also Am. Jour. Sci. (2), Vol. 15, note, page 240, which is as follows : " The character of the decomposition which takes place is somewhat curious and unexpected: it was first supposed that equal volumes of CI, N20, and N were given off, but it is shown that nearly all the NH4HO, with its equivalent of HN03, is converted into N20, the liberated HCl mixing with the excess of HN03. A little of the NH4Cl-f-HN03 does not undergo the decomposition first supposed, and in this way only can the small amounts of N and CI be accounted for." " Some nitrous or hyper-nitrous acid forms during the whole process if cone. HN03 is used, little or none if dilute HN03." The action of NH4N03 on NH4C1 is theoretically as follows: 2(NH4N03)+NH4Cl=5N+Cl+6HaO. ANALYSIS OF DOLOMITE. 33 The following are possible reactions : 8NH4C1+ioHN03=9N20+8Cl + 2iH20, 2HN03+2NH4C1=N20+2C1+2N+5H20, HN03-fNH4Cl=HCl+N20-f-2H20, and 2HN03+NH4Cl=NaO+Cl+NOa+3HaO, and HCl-r-3HN03=NO + Cl+NOCl2-f-N02+4Cl+5H20. Note 8. Determination of C02.—/. By loss. Fres., § 139, II., d, bb, and cc. Weigh out 1.0 to 2.0 grms., place in the Geissler apparatus, fill the proper portions of the apparatus with HCl (dil.) and with H2S04 (cone.) respectively. Weigh apparatus. Cau- tiously let the HCl flow on the min- eral, warm gently, heating at the last till the solution begins to boil. Cool apparatus and weigh. For details consult Fresenius, as above. Do not hurry this process too much. II.—By direct weight. Consult Fres., § 139, II., c. Arrange apparatus as in Fig. 4. Suspend tubes by wire loops on nails. a contains soda-lime. c is a flask of about 200 c.c. capacity. d contains cone. H2S04. ^contains pieces of pumice-stone saturated with cone. H2S04; avoid much liquid in the bend. f contains pumice-stone saturated with anhydrous CuSO, 24 QUANTITATIVE ANALYSIS. N.b.—Make a strong hot solution of CuS04+5H20, add pieces of pumice-stone, boil hard, evaporate to dryness and ignite well. The product should be nearly white. g contains in outer tube, soda-lime ; in inner tube, {h) pumice-stone saturated with H2S04 ; weigh these together both before the absorption and after. Place i.o to 1.5 grms. mineral in c, weigh g and h, and connect apparatus ; a is not attached at first. Pour a little water through the funnel tube into c, then add gradually HCl, diluted one-half with water. Attach a, and aspirate gently. Heat cautiously to incipient ebullition ; maintain this a few moments, and let cool while the aspiration continues. Weigh — increase of weight gives C02. Note 9. Calculation.—Normal dolomite contains : 30.4 per cent. CaO. 47.8 " CO. 21.8 " MgO. 100.0 Having estimated these constituents, calculate the ANALYSIS OF BRONZE. 35 amounts of CaC03 and MgC03, and report under " Special Remarks," thus : CaO : C02 = CaO found : C02 required or M. MgO : C02 = MgO found : C02 required or N. and M + N must = C02 found, nearly. Analysis No. 8 — Bronze. To be determined, Sn, Pb, Cu, Zn. A.—Determination of Tin. Dissolve about 0.6 grm. bronze filings, carefully freed from accidental impurities, in moderately dilute HN03, in a flask in the neck of which is placed a small glass funnel. After complete solution (except the Sn02), transfer con- tents to a porcelain dish, evaporate to dryness, moisten with HN03, add H20, and filter from the Sn02. Dry this residue, ignite in porcelain, and weigh. Fres., § 126, I., a, and § 91. B.— Determination of Lead. To filtrate from A add dilute H2S04, evaporate until fumes of H2S04 appear, or the residue is nearly dry, let the dish cool, then add water, and filter from the PbS04. See Fres., § 163, 2, and § 116, 3, a, ft. Dry, ignite, and weigh precipitate. See Fres., § 83, d. C —Determination of Copper. The filtrate from B. should not measure more than 100 c.c. Place the solution in a large platinum dish, arrange the Bunsen cells of a galvanic battery, connect the zinc 36 QUANTITATIVE ANALYSIS. element with the platinum dish, and the carbon element with a small piece of platinum foil which is immersed in the liquid. Let the battery run four or five hours. Take out a drop of the solution with a pipette, place on a watch glass and test for Cu with H2S. Pour out the solution when the precipitation is completed, and wash thrice with small quantities of water. Then wash the copper film with alcohol twice, dry in the hand, over a Bunsen burner, at a very gentle heat, and weigh quickly. N.B. — It is advisable to test solution for Cu before proceeding further. D. — Determinaticn of Zinc. Heat the filtrate and washings from C to boiling, add excess of Na2C03, boil a few minutes, wash by decantation hot, then on filter, Dry, ignite, and weigh as ZnO. Fres., § 108, I, a, and § yy. Analysis No. 9.— Coal. (Proximate Analysis.) To be determined, Moisture, Volatile and Combustible Matter, Fixed Carbon, Sulphur, and Ash. A — Determination of Moisture. Pulverize the coal very finely, heat one to two grms. in a half ounce platinum crucible for fifteen minutes at H5°C. in an air-bath, cool and weigh. Repeat this desiccation in the air-bath, weighing at intervals of ten minutes, until the weight is constant or begins to rise. Loss of weight gives moisture. In reporting, give exact temperature at which it was determined. N.B.—The increase in weight is due to oxidation of the coal; it generally begins after heating analysis of coal. 37 thirty to ninety minutes in the air-bath. Anthracite coal may be heated an hour or more. See Chem. News, Am. Repr., Vol. V., p. 80. B. —Determination of Volatile Combustible Matter. Heat the same crucible with contents, closely covered, to bright redness over a Bunsen burner, exactly three and one-half minutes, and then without allowing the crucible to cool, heat strongly before the blast-lamp, exactly three and one-half minutes more. Cool and weigh. The loss gives the volatile and combustible matter, and includes half the S in the FeS2. See F below. C —Determination of Fixed Carbon. Heat crucible and contents, uncovered, over Bunsen burner, until all carbon is burned off and the weight is constant. This takes from one to four hours or more. Loss in weight = fixed carbon, including half the S. D- — Determination of the Ash. The difference between the weight last obtained and that of the crucible gives the weight of the ash. Note color of the ash. E. —Determination of Sulphur. Secure a sample of anhydrous Na2C03, shown to be ab- solutely free from S by the silver test. Weigh out about two grms. coal in fine powder, mix with about ten grms. NaN03 and ten grms. Na2C03 on glazed paper. The sodium salts need not be weighed ac- curately ; KN03 may be used in place of NaN03. Deflag- rate in a covered two-ounce platinum crucible, heating over 38 quantitative analysis. a Bunsen burner; add the mixed coal and sodium carbonate little by little, replacing the cover of the crucible quickly each time. Do not expect to effect a perfect fusion. Place the crucible and contents in a casserole, add water, and digest until the mass is disintegrated, and the crucible can be removed. Add cautiously an excess of HCl, heat to boiling, and throw down the H2S04 with BaCl2 as usual. If flocks of Si02 remain insoluble in HCl, evaporate to dryness on water-bath, heat until HCl is expelled, add water, filter, and proceed as above. If the BaS04 is red- dish after ignition, wash with solution NH4C2H302 and then with pure water, dry, ignite, and weigh again. The BaS04 may also be purified by solution in cone. HaS04 and reprecipitation with water. Second Method for Determining Sulphur. — Put two to five grms. powdered coal in a flask holding a litre; add IOO c.c. HN03 and five grms. powdered KC103, heat to boiling, adding more reagents as needed; continue until all the carbon is oxidised. Transfer to a dish, evaporate to dryness, add HCl and water, throw down H2S04 with BaCl2, and proceed as usual. Consult Hayes's article in Am. Chem., Feb., 1875, also Wittstein's article in Am. Chem., April, 1876. F. — Calculations. Theoretically we should deduct half S from the volatile combustible matter (because iron pyrites loses one-half its sulphur at a red heat), one-eighth S from the fixed car- bon, and three-eighths from the ash. (2FeS become Fe203, or 8 X 4= 32 reduces to 8 X 3 = 24.) Practically half the amount of sulphur is deducted from the volatile combustible, and half from the fixed carbon; reports should be made out accordingly. ANALYSIS OF COPPER PYRITES. 39 G. — Estimation of Carbon and Hydrogen. Ignite one grm. of coal with PbCr04 in a hard glass tube 0.25 metre long. Pass the H20, C02 and H2S04 formed through two U-tubes, one containing ignited CaCl2, and the other a solution of Pb(N03)2, and through a potash bulb. The increase in weight of the first U-tube gives the H20, and that of the potash bulb the C02. Calculation of Calorific Power. — One part of carbon in burning yields 8,080 calorific units, and one part of hydrogen in burning 34,460 calorific units. Hence to calculate total calorific units in a coal, multiply the percentage of C by 8,080 and divide by 100; also multiply the percentage of H by 34,460 and divide by 100. Add the quotients. (A calorific unit is the amount of heat necessary to raise one grm. of water from o° to i° C.) See Chem. News, XXXIV, p. 233. 1876. Analysis No. 10. — Copper Pyrites. Determination of Copper. Pulverize very finely. Weigh out exactly 2 grms., place it in a flask of about 300 c.c. capacity and covered with a small funnel, the stem of which is slipped into the neck of the flask. Add 20 c.c. cone. HN03, 5 c.c. cone. HCl, mix- ing these in flask under the hood. Digest some minutes, then add cautiously 20 c.c. cone. H2S04 and boil hard un- til fumes of H2S04 appear abundantly. Cool, add water with caution, dilute not too largely, filter from residue (Si02, CaS04, etc.), and wash. Test residue for copper before the blow-pipe. Dilute filtrate to 200 c.c. exactly, mix well by pouring into a dry beaker and back again three or four times; divide in halves by taking out 100 c.c. with a pipette 4o QUANTITATIVE ANALYSIS. and place in a platinum dish previously weighed. (N.B.— Volumetric apparatus as sold is rarely reliable, therefore test pipette and flask before measuring as above.) Arrange two cells of a Bunsen battery, placing the " battery acid " (one part of H2S04 diluted with 8 to 10 of water) in the outer cell and "battery fluid " (K2Cr207-f H2S04+H20) in the inner. Connect the zinc (-J-) pole with the platinum dish, and the carbon (—) pole with a piece of platinum foil which is immersed in the liquid. Cover the platinum dish with two pieces of glass plate, one each side of the platinum foil, to prevent loss by spattering. Or use the cone or spiral described in Chem. News, XIX, p. 222 (1869). See also Crookes Select Methods, pages 187-200. It is best not to let the battery run all night; prepare the solutions on one day and start the battery the next morning. Four hours or more usually suffice for complete precipitation. Test a few drops of the solution with H2S. When precipitation is complete, pour off liquid, wash copper with distilled water three or four times (work rap- idly), then with strongest alcohol twice; drain the alcohol off, dry the copper at a very low heat, holding the plati- num dish in the hand over a small flame, which must not touch the dish, and weigh immediately. Next treat the remaining 100 c.c. solution likewise ; the two determina- tions should agree to about 0.2 per cent. Analyses No. 11 and No. 12. Introductory Note 3 on Volumetric Analysis. Definition. " Volumetric Analysis is a form of quantita- tive analysis in which we seek to estimate the amount of a substance from the determinate action of reagents in VOLUMETRIC ANALYSIS. 41 solutions of known strength, the amount of the reacting substance being calculated from the volume of the liquid used." The first principles and method of procedure have been foreshadowed in Analysis No. 3, III., Determination of Iron by Marguerite's method. For explanation of gen- eral volumetric methods, see Fres. § 54, and consult Sut- ton's Handbook of Volumetric Analysis, also Mohr's Lchr- buch der chemiscJi-analytiscJien Titrirmethodc. Principles. When volumetric analysis first came into use, the standard solutions were so prepared as to give results in percentages ; thus in Alkalimetry, one standard solution of acid was used for potash, another for soda, etc. The modern system is based on the fact that acids and alkalies (as well as other reagents) neutralize each other in the proportion of their molecular weights, or of simple multiples of the same ; consequently standard solutions are so prepared that one litre contains one-half or the whole of the molecular weight of the reagent weighed in grms. For example, the molecular weight of HCl being 36.5 and that of KHO 56.1, 36.5 grms. of HCl exactly neutralize 56.1 grms. of KHO, and if these respective amounts be dissolved in one litre of water, the whole of one solution will not only neutralize the whole of the other, but any aliquot part of one will exactly neutralize a similar aliquot part of the other. And by using graduated vessels, (bu- rettes,) the amount of reagent used is determined by the volume of the solution. (Before employing burettes, pipettes, and graduated flasks, care should be taken to test the accuracy of the graduation.) Standard Solutions. Solutions containing the molecu- lar weight of the reagent expressed in grms. per litre are called normal solutions ; in the case of di-basic acids (H2S04, H2GA etc.) and of" di-acid " alkalies (Na2COa) 42 QUANTITATIVE ANALYSIS. one-half the molecular weight of each is taken, making half normal solutions. The standard solutions of the following reagents are made with the quantities indicated : Oxalic acid H.2C204+2 aq. 63 grms. per litre Sulphuric acid H2S04 49 " a Hydrochloric acid HCl 36.5 " « Sodium carbonate Na2COa 53 " M Potassium hydrate KHO 56.1 " U Ammonia NH3 17 " (« The point of neutralization or end reaction is determined by adding to the solutions some organic coloring-matter which changes in hue under the influence of an alkali or an acid. The " indicators" commonly used are litmus solution and cochineal solution. Alkalimetry. (Cf. Sutton's Handbook.) 1. Preparation of Litmus Solution.—Digest 5 to 6 grms. litmus with about 200 c. c. water for half an hour or more; decant the clear liquid or filter; add very dilute HN03 drop by drop, until the color is changed to violet. If properly neutralized less than one-tenth c.c. of stand- ard acid should distinctly redden one c.c. litmus in 100 c.c. of water. 2. Sulphuric Acid.— Mix about 60 grms. cone. C.P. ALKALIMETRY. a-% H2S04 of sp. gr. 1.840 with three or four times its volume of distilled water ; cool and dilute to one litre. The ex- act standard of this solution is determined by testing with sodium carbonate, as below. 3. Sodium Carbonate Solution. — Weigh off about 12 grms. anhydrous C.P. Na2C03; heat in a porcelain dish to low redness, stirring until moisture is expelled; place in a desiccator to cool. Weigh out accurately 10.6 grms. of this, and dissolve in distilled water. Dilute to exactly 200 c.c. This gives a half normal solution, each c.c. of which contains 0.053 grm. of sodium carbonate, as shown by this simple calculation: Na2 = 46 C =12 03 = 48 Mol. wt. of Na2 CO., 106 One-half the mol. wt. = 53 200 c.c. : 1 c.c. = 10.6 grms.: 0.053 grms. This solution serves to standardize the sulphuric acid. Standardizing the Sulphuric Acid.—Take of the Na2C03 solution, 20, 30, or 40 c.c, accurately measured, place in a wide-mouthed flask of about 300 c.c. capacity ; add litmus solution, and run in H2S04 solution from a burette until a wine-red color is obtained; boil hard to expel C02, and add more acid until the color is permanent. Read off the c.c. used. Repeat the process. Suppose 30 c.c. Na2C03 solution required 25 c.c. H2S04 solution. Then 5 c.c. (30 — 2 5) water must be added to every 25 c.c. of the acid solution to make it normal. Measure, therefore, the H2S04 solution carefully and add the necessary amount of water. Suppose the H2S04 solution measures 900 c.c, since 900=25X36, then 36 X 5, or 180 c.c. water must be added. Add the water, mix well, and again determine 44 QUANTITATIVE ANALYSIS. the standard : one c.c. of the Na2 C03 solution should ex- actly neutralize one c.c. of the H2S04 solution. In case of difficulties the exact standard of the acid should be deter- mined gravimetrically by precipitating 10 or 20 c.c. with BaCl2, and calculating from the BaS04 obtained the amount of H2S04 in one c.c. Carminic acid being stronger than carbonic acid, a solu- tion of cochineal is sometimes substituted for litmus, in which case boiling may be dispensed with. The dyestuff tropaeoline has recently been proposed as an indicator in alkalimetry. Cf. Ber. d. chem. Ges. XI, 460 (1878). Deci-normal Solution of Acid.— Call the above normal solution "No. 1 ;" take 100 c.c. of No. 1, put into a litre flask, and dilute to one litre. Call this deci-normal solution " No. 2." A.—Valuation of Soda Ash. (Determination of Na2C03.) Place about 12 grms. powdered sample in a platinum crucible or porcelain dish ; heat moderately for some min- utes over a Bunsen burner, until all moisture is expelled; cool, weigh out exactly 10 grm.; dissolve in water; dilute to one-half litre and mix well. Take out 50 c.c. solution (which contains one grm. soda ash), and determine the amount of normal acid needed to neutralize, adding litmus as before, and boiling to expel C02. Suppose 50 c.c. solution soda ash required 1 5 c.c. stand- ard acid, then °-53x *m.....^°° ~ 79-5 Per cent- Na2C03. See Fres., § 207, p. 500. These results are only approximative and preliminary, and the operation must be repeated, finishing with the deci-normal solution No. 2, as below. Take another 50 c.c. of soda ash solution; run from a burette 12 c.c. of solution "No. 1," and then ACIDIMETRY. 45 finish with solution " No 2." Of course, in calculating, 10 c.c. of No. 2 equals one c.c. of " No. i." B- — Valuation of Pearl Ash. Proceed as before; weigh quickly the salt cooled in a desiccator, for it is very hydroscopic. In calculating, use the factor 0.0691. The Residual Method of Titration.— This method has great advantages over the foregoing method, especially when carbonates are in question ; the sharpness of the end reaction being much increased by the absence of C02. The process is as follows: Super-saturate the soda ash solution with normal acid in excess; then add normal pot- assic hydrate (and decinormal also) until the neutral point is reached. (The normal KHO is mentioned in the next paragraph.) Since one c.c. acid= one c.c. alkali, substract the number of c.c. of standard alkali from the number c.c. of standard acid added in the first place, and then calculate as usual. ACIDIMETRY. Generalities.—The value of strong acids, especially HCl, HN03, H2S04, is frequently deduced from the Specific Gravity as determined by the hydrometer. See tables in Fres., pp. 488, 491, showing percentages of acids in solu- tions of different densities. When titration is desirable, standard KHO solution is used, and in accordance with the principles already stated. Preparation of Standard Alkali.—Take about 60 grms. KHO, dissolve in 1 litre of water, add Ca(H0)2 to throw down carbonates, boil, let settle, and syphon off. Deter- mine the exact standard of this with normal and deci- normal acid. 46 QUANTITATIVE ANALYSIS. A—Valuation of HCl. Take 5 to 50 c.c. acid, according to strength, dilute to a definite volume, take an aliquot part, add litmus and run in the standard KHO as described. In calculating multiply the number of c.c. of KHO added by .0365 X 100, and divide this product by the num- ber of c.c. of acid taken X Specific Gravity of the solution as determined by the hydrometer. Example.—Took 10 c.c. HCl solution, having a Specific Gravity = 1.025 '■> since 1 c.c. of water weighs 1 grm., the weight of acid taken — 10.25 grms. The acid solution required 8 c.c. KHO, whence 8 X -0365 X 100 ---------------= 2.84 per cent. 10.25 ^r B.—Analysis of Vinegar. A. Determine the acetic acid by titration, using cochi- neal solution, or with methylaniline violet, as in the " Witz method" {Am. Chem., Vol. VI, page 12), or use Mohrs method, as follows •: Add to a known quantity of acid a weighed quantity (in excess) of pure precipitated dry CaC03. After de- composition is nearly complete in the cold, boil to expel C02, filter, and wash the excess of CaC03 in hot water. Dissolve the CaC03 in excess of normal HCl, and deter- mine the HCl remaining by means of normal KHO, or NaHO and litmus solution. The results with dark colored vinegars are good. B. Determine water by drying at ioo° C. to constant weight, and allow for alcohol and acetic acid. CHLORIMETRY. 47 C. Determine alcohol by neutralizing about 300 c.c. vinegar with CaC03 and distilling off some measured amount, say 150 c.c. Then determine specific gravity by weighing, and from this calculate the per cent, of alcohol. D. Determine the grape sugar. (See Analysis No. 33.) Analysis No. 13.—Chlorimetry. Constitution of Bleaching Powder. Bleaching powder is formed thus : 2CaH202 -f 2C12 = 2H20 + CaCl202,CaCl2. The composition of bleaching powder is variously given. The following are some of the formulae. " Quelques Chimistes," CaCl2 4- H202. Watts, CaCIO + CaCl, Ca20 + 2H20. Bloxam, CaO C120 -f- CaCl2 2CaO -f- 4H20. Roscoe, CaCl202. Muspratt, CaO Cl2 2H20. Fownes, CaCl2 -f- CaCl202. Calvert, 2CaCl2 -J- CaCl202. Thorpe, Ca3H606Cl4-= CaCl202 + CaH202+CaCl2+ 2H20. Kolb, (2CaO,Cl2H20), CaH202. Rose, (CaCl2, Ca202) Ca02Cl2 + 4HA Stahlschmidt's theory of its formation: Bericht D. Chem. Ges., 1875 : 3 CaH202 + 4CI = CaCl2 + CaCl202 + CaH202 -f- 2H20. See paper on Constitution of Bleaching Powder, by Dr. Lunge in American Chemist, Vol. V, page 454. 48 QUANTITATIVE ANALYSIS. When allowed to stand in contact with air and light, it decomposes, CaCl2 increasing, and the CaClO decreas- ing. Dry chloride of lime, at 500 C, decomposes thus :— (Thorpe.) 3Ca3H606Cl4 = 5CaCl2 + Ca(C103)2 + 3CaH202 + 6H20. By the action of water chloride of lime decomposes thus: Ca3H606Cl4= CaH202 -f CaCl2 + CaCl202 -f- 2H20. The value of the commercial article depends wholly upon the amount of " available chlorine," viz.: the CI in the hypochlorite, which is thus constantly varying. The strongest contains 38.5 per cent, available chlorine. One or two per cent, of this is present as calcium chlorate, which is without bleaching power. Action of Acids on Bleaching Powder. — Action of hy- drochloric acid: (CaCl202 + CaCl2) -J- 2HCI = 2CaCl2 + 2(HC10). Action of dilute sulphuric acid: (CaCl202 + CaCl2) + H2S04 = CaS04 -f CaCl2 + 2(HC10). Further action of concentrated sulphuric acid : CaS04 + CaCl2 + 2(HC10) + H2S04 = 2(CaS04) + 4CI -f 2H20. CHLORIDE OF LIME. 49 Valuation of Chloride of Lime. Penot's Method. From Fresenius' Quant. Analysis, §212. Based on the conversion of an alkaline arsenite, into an arseniate by a solution of chloride of lime. As203 -f CaCl2Oa = As2Os + CaCl2. The end reaction is determined by KI and starch, un- decomposed hypochlorite turning this mixture blue. (a.) Preparation of KI Starch Paper. — Boil three grms. starch, in 250 c.c water, add one grm. KI, one grm. Na2C03 -f- aq.; dilute to 500 c.c. Moisten paper with this solution and dry. {b.) Preparatioji of Solution of As20r — Dissolve ex- actly 4.95 grms. pure sublimed As203 with 25 grms. Na2C03 -j- aq. (free from S) in 200 c.c. water. Boil until N dissolved and dilute to one litre. Make a — solution. Since it is difficult to weigh out exactly this amount, take any number and dilute proportionately. If .5.013 grms., then 4.95 : 1000 = 5.013 grms. : 1012.7. Add then 12.7 c.c. to the litre. One c.c. of this solu- tion = 0.00355 CI. (c.) Process of the Determination. — Mix sample well; weigh out 10 grms., rub in mortar with 50 or 60 c.c. water; settle; decant turbid liquid into a litre flask. Repeat. Fill up to mark, and mix. Fill a burette, take 50 c.c, run it into a beaker, add the standard As203 solution, stirring until a drop of the so- 50 QUANTITATIVE ANALYSIS. lution no longer gives a blue mark on the KI starch paper. Repeat on fresh amount. Caution: Shake, and draw off turbid liquid. {d.) Calculation. c.c. As20, solution usedXo.oo355X ioo ^, ---------±--------------------±z-±-----= per cent. CI. Amount taken [French chlorimetrical degrees represent the number of litres of CI at o.°C. and 760 m.m., which one kil. of sample should yield. Now one litre of CI weighs 3.177 grms.; hence 31.77 per cent. = 100 degrees. See foot-note on p. 505 of Fres. Quant. Anal.] The amount of calcium chloride present may be de- termined by first estimating the hypochlorite as above, and then adding to the second portion of 50 c.c. a slight excess of NH4HO and warming. 3 CaCl202 + 4 NH3 = 3CaCl2 -f 6H20 + 4N. Neutralize the solution with HN03 and determine the CI by AgN03. The amount of chlorate may be determined by heating a third portion with ammonia, then acidulation with pure H2S04 and digesting with Zn. Ca(C103)2 + 12H = CaCl2 + 6H20. Again determine the CI by AgN03, and the increased amount over the second determination gives the CI exist- ing as chlorate. (Thorpe.) A,ialys>s No. 14. —Type Metal. To be determined Pb, Sb. Sn (Zn and Fe?). and he^in^SntW gr?" ^P^VJ1 m.0Jderately cone. HNO„ adding enough H,C,II40, to hold up the antimony, excels o? ifln?lY' D,^f arid add acid until all but the SnC\ is dissolved. ' See4 Fres , § 164, 14. b. Expel excess of HNQ, by concentration of liquid, but not to dryness. Filter and wash. See Note 1. Residue a. o 7 j • Q n c Solution a. " - (+Sb/) t„S.b> Pb, Zn (Fe). Add HsS04 and evaporate to small bulk, add alcohol and let stand Dry, _ ignite.|« hours. See Fres., § 116, 3. «, n> and § 83, d. Filter and wash with water containing a little and weigh. jH.&U an.d then changing recipient of filtrate, wash thoroughly with alcohol. Be careful to Test for lead.|exPeI a" H?b0. from mt^- See Fres.. § 126. 1, a. and §91, a. See also Note 2, below. Precipitate b PbS04. Dry, ignite in porcelain, and weigh. See Fres § 83. d. Filtrate b. Sb, Pb, Zn (Fe). Saturate with H„S gas, warming solution with a current of steam. Filter and wash. See Fres.. § 164, A. 1. Precipitate c. Sb2S, + PbS. Digest with yellow NH4HS, filter, repeat digestion, filter and wash. See Fres.. § 1I4. 14, b. Solution c. Zn and Fe. (To determine these, thro w down Fe as basic acetate. and Zn as car- bonate § 108, 1. a § 77, a.) Fres.. and Residue d. PbS. oxidize with UNO dry. ignite, and weigh as PbS04 Solution d. Add excess of HCl and wash. Solution e. NH4C1. Reject. Precipitate e. Treat precipitate of Sb.,S„ + S on filter (to remove S). by wash- ing with CS„. transfer to a weighed porcelain crucible, add fuming UNO... heat, add more acid, evaporate to dryness, ig- nite, and weigh as Sb.O,. If dark colored add more UNO.., heat, ignite, and weigh again. Fres., § 125, 2, b. a. See Note 1. 52 QUANTITATIVE ANALYSIS. Note i. — Some of the tin may go into solution as nitrate of tin, if the nitric acid be dilute, and thus appear in Precipitate c mixed with the sulphide of antimony; in this case they should be separated by F. W. Clarke's method, which is based on the solubility of the sulphide of tin in oxalic acid, and details of which may be found in Crookes' Select Methods, page 249. For another method see Fres., § 165, 4, a, also § 165, 7, a. Note 2. — On the other hand, some of the antimony and lead may refuse to dissolve and remain with Residue a, in which case proceed as follows : after igniting and weigh- ing the Sn02 -f- Pb ? -f- Sb ? fuse with Na2C03 and sulphur in a porcelain crucible. Dissolve in warm water and filter from the residue of PbS, which may be treated with HN03 in a porcelain crucible and weighed as PbS04. To the alkaline solution add slight excess of HCl and collect precipitate of SbS3 -f- SnS2 -\- S on filter; dry and remove excess of S by washing with CS2, transfer to porcelain capsule, oxidize with HNOs evaporate to dryness, fuse with NaHO in a silver dish, dissolve the mass in a mixture of three volumes of alcohol and one of water, and filter from the antimoniate of sodium. For details, see Fres., § 165, 4, a To the solution containing stannate of sodium, add HCl, saturate with H2S, and treat the precipitated SnS2 as usual. See Fres., § 126, I, c, and § 91. Consult article on the Estimation of Antimony, by E. H. Bartley, in American Chemist, Vol. V, page 436; also paper by Dr. Clemens Winkler, in Fresenius' Zeitschrift fur Analytische Chemie, Heft 2, 1875. Analysis No. 15.—Zinc Ore, Determination of Zinc. Pulverize finely; heat about 2 grms. ore with 10 c.c. HCl + 5 c.c. HNO., 4" 10 c.c. H2S04 in a flask. Boil till fumes of H„S04 appear. Cool, add II„0 carefully, warm and filter, wash thoroughly._________________ Residue a. Si02 + PbS04. CaSO,, etc. Testfor zinc, and. if found, treat again With acid. Solution a. Nearly neutralize with cryst. Na„C03, dilute, add NaC2H30, (about 5 grms.), boil ten minutes and filter hot. Wash hot by decantation. See Note 1 below, and Fres.. § 113, 1, d. Precipitate b. Fe203 4- Al2Os as basic acetates. Filtrate h. Add Br water to the liquid, and digest for some time. as MnO, is precipitated. Fres., § 159, 4, a. Repeat so long Precipitate c. MnO, + xHaO. Filtrate c. Expel Br by boiling, add a little IICTI.,0.,. saturate with H„S gas, wash the ZnS with H2S water on the filter, carefully covering the funnel with a watch-glass. Cf. Fres.. § 108, 1, b. See Note 2. Filtrate d. Examine carefully for Zn, and if present repeat as with Filtrate c. Precipitate d. Dissolve on filter with warm dilute HCl, add a very little KCIO, boil to oxidize the ZnS, filter from S if necessary, and add Na.,CO... Fres., § 108, 1, a. and § 77. Wash, dry, ignite, and weigh as ZnO. Note 1 —For the precipitation of Fe as basic acetate, the solution must be very carefully neutralized with crystallized Na,C03, ending with a dilute solution of Na2COs, and striking as deep brown-red a color as possible. Cf. Note 11, Analysis No. 21. . Note 2.—For properties of ZnS and various methods of determining Zn, see article by Hugo lamm in American Chentist, Vol. II, p. 298. Analysis No. 16.—Chromic Iron Ore. Scheme I. May contain FeO, A1„03. Cr,03, Mn2Os, CaO, MgO, LiO,(Ti02). Fuse 0.5 grms. ore, ground to an impalpable powder, in a large platinum crucible with 6 grms. KHS04 for twenty minutes; add H2S04 from time to time, and fuse again at a higher temperature. Add 3 grms. pure Na,C03 and 2 grms. NaNO,, adding the latter in small portions at a time during an hour, at red heat, then heat fifteen minutes to bright redness. A little KHO added to this fusion facilitates it. Cool, remove the mass from the crucible with hot water, filter hot, and wash the residue. Fres., § 160, 8, a. Residue a. Digest with HCl, and filter from res- idue. The HCl solution is rejected. If much undecom- posed ore remains, fuse again as before. Filtrate a. Evaporate with excess of NH4NO.t on a water-bath nearly to dryness, and heat until all free NH4HO is expelled. Add H20, digest, and filter. Fres., § 160, 8, «, 77. Residue b. AhO, Mn26,," Re-fuse before. Si02(TiO„) also" Cr,0~r and treat as Add second filtrate to filtrate b. Filtrate b. Boil with HCl and alcohol, expel excess of alcohol; when fully reduced add NH4HO, boil, filter hot, wash thoroughly by decantation. Fres., § 106, 1, a. Filtrate c. Reject if colorless, or contains no Cr,0,. Precipitate c. Cr,03. Dry, ignite, and weigh. Fres.", § 76. 4± iO a > H H > < > > Analysis No. 16. — Chromic Iron Ore. Scheme II. Pulverize very finely, take 0.5 grm., fuse as in Scheme I. Dissolve in water and filter. Residue a. Fe2Os, A1203, undecomposed ore, etc. Treat with HCl, digest, filter, and wash. Filtrate a. Contains Na,Al204, Na,Cr04, Na2Mn04, Na2Si03, etc. Add (NH4)2C03, and heat nearly to boiling. Residue b. If not very small in quantity, must be re-fused as before and added to filtrate a. Filtrate b. Fe,Or etc. Reject. Residue c. Al2OsSi03, etc. Filtrate c. Na,CrO, solution must be yel-low. Neutralize with UNO.,. and add a neutral solution of Hg(NO,)=. Wash the precip-itate with dilute solution of Hg(NOs)2. Dry, ignite the HgCrO.,, and weigh the Cr2Oa resulting. For other methods, see Fresenius' Quant. Analysis, Editor's Appendix, page 621 (Amer- ican Edition, 1870). Consult also paper by E. F. Smith, in American Journal of Science, [3] xv, p. 198. 56 QUANTITATIVE ANALYSIS. Analysis No. 17. — Pyrolusite. Determination of ]\Jn02. Employ Fresenius and Will's method as described in Fres. Quant. Analysis, edition of 1870, pages 509-12, § 215, A. See also Mohr's Titrirmethode § 215, pp. 617-638 (ed. 1874). Take 3.955 grms. of ore, and use Geissler's carbonic acid apparatus if available. Consult also the following article: " On the Estimation of Peroxide of Manganese in Manganese Ores," by E. Scherer and G. Rumpf, Chemical News, American Re- print, Vol. VI, page 82, February, 1870. Analysis No. 18. — Feldspar. A- — Determination of Alkalies. Prof. J. Lawrence Smith's method. See Am. J. Sci. [3] I, 269. Also Fres., § 140, II, b, y. Pulverize well in an agate mortar. Weigh out one grm. of the silicate. Mix well in an agate mortar, first, with about one grm of NH4C1 (pure enough to sublime without residue), and, secondly, with about eight grms. C. P. pre- cipitated CaC03; add the latter in three or four portions, mixing well after each addition. Transfer the mixture by means of glazed paper to a platinum crucible. Apply the heat of a Bunsen burner to the upper portion of the crucible first and gradually carry the flame toward the lower part, until the NH4C1 is completely decomposed, determination of alkalies. 57 which ensues in four or five minutes. Then heat before the blast-lamp, not too intensely, for thirty to forty min- utes. This operation is greatly facilitated by using a special apparatus devised for the pur- pose by Prof. J. Lawrence Smith, and represented in Fig- 5- The stand H supports on its rod G a cast-iron plate B perforated by a hole large enough to admit the some- what elongated crucible A; the bottom of the crucible projects within the sheet iron chimney C which is held in its place by the hook N. When heat is applied to the bottom of the crucible by the flattened burner F the decom- position proceeds regularly and is completed in about one hour. Cool the crucible, place it in a porcelain casserole, and digest the semi-fused mass with boiling water until tho- roughly disintegrated. This may take some hours. Then filter from the residue (Si02, Fe2Os, A1203, Mn203(?), CaO, etc.), and wash well with about 200 c.c. of water. All the alkalies of the silicate are converted into chlorides and are now in the water solution. Add to this solution NH4HO and (NH4)2C03 with a few drops of (NH4)2C204. Evaporate without filtering, on a water-bath, to about 50 c.c, add a little NH4HO, and filter through a small filter (No. 2) into a weighed platinum dish. Evaporate to dry- Fro 5. 58 QUANTITATIVE ANALYSIS. ness on a water-bath, ignite very gently to drive off a little NH4C1, and weigh. If the residue is not perfectly soluble in water, and quite white, dissolve, filter off, evaporate, ignite, and weigh again. This gives the weight of the KC1 +. NaCl. Next determine the K, either by separating it with PtCl4 and alcohol in the usual manner, or by gravimetric or vol- umetric estimation of the total CI in the weighed chlorides. For calculation, see Fres., § 197, a. Consult also Crookes' Select Methods, pages 13 and 14. B. — Determination of Si02, A1,03, Fe203> CaO, and MgO. Fuse two grms. mineral with six grms. K2COs + six grms. Na2COs. Moisten with water, digest, add excess of HCl, evaporate to dryness, expel HCl in air-bath, add water and HCl, and filter from Si02. Continue exactly as in Analysis No. 7. Appendix to Analysis No. iS.—Analysis of Soluble Silicates. May contain SiO„ A1,0.,, FeO, CaO. MgO, Na,0, K,0, H,0. Pulverize, weigh out four grms., moisten with water in casserole, add cone. HCl, evaporate to dryness on water-bath. Dry in air-bath at ioo°-ii5° C. Moisten with HCl, add water, digest, and filter. Residue a. SiOo. dry, ig- nite before the blast lamp, and weigh. Solution a. Oxidize the FeO if necessary, dilute to 400 c.c., and divide into two equal portions. Solution a1. 200 c.c. De- termine Al.O... Fe/).;. CaO and MgO, exactly as in Analysis No. 7, Dolomite. Solution a'1, 200 c.c. Add solution of Ba(HO), in excess and filter. Fres., §153, B, 4, a, a. Residue a. A1..0.., Fe,03, MgO, etc. Re- ject. [Fe may be determined here volumetrically.J Solution b. Add (NH4)2C03, boil and filter. Residue c. CaC03 BaCO, etc. Reject. Filtrate c. Add HCl cautiously. Evaporate to dryness, and heat gently over Bunsen burner until all NH,C1 is expelled. Dissolve residue in water, filter into weighed dish. Evaporate, dry. ignite, and weigh as NaCl+KCl. Dissolve in water and determine K directly as K,PtCl,;, or indirectly by estimation of CI, in the mixed chlorides. See Fres., § 197, a, for calculation. 6o QUANTITATIVE ANALYSIS. Analysis No. 19. — Iron Slag. To be determined: Si02, FeO, MnO, A1203, CaO, MgO, S, P2Os. Pulverize finely; weigh out exactly five grms.; mix on glazed paper, by means of a horn spatula, with fifteen grms. anhydrous Na2C03 and fifteen grms. K2C03, together with one grm. NaN03. These fluxes need not be accurately weighed. Put one-third the mixed slag and fluxes into a two-ounce platinum crucible, and heat over a Bunsen burner until by settling down room is made for more. Heat twenty minutes or more before the blast-lamp. Cool suddenly, place in a casserole, and treat with boiling water until thoroughly disinte- grated. Remove the crucible and add excess of HCl little by little, avoiding loss of liquid by violent efferves- cence; evaporate to dryness on water-bath, expel HCl completely by drying (not above 1150 C.) in an air-bath. Moisten with water, add HCl, digest, and proceed as per scheme on following page. i Filter the solution obtained as directed on page 60. Residue a. m SiO,. Dry. ig- nite, and weigh. N.B. — Check Si02 by fusing 1 grm. slag as a- bove and follow- ing details there given. Solution ax. 100 c.c. AddBaCl„and treat the BaS04 in the usual manner. Report S. Filtrate from BaS04 may be kept for deter- mining Fe in case of accidents. Filtrate a. Dilute to 500 c.c. and divide into three portions. Solution a1 Add excess of NH4HO, wash, dissolve in II2S04, and de- termine the Fe with K,Mn2Oft. Cf. Note 18, Analysis No. 21. Solution a3. 300 c.c. Cool, nearly neutralize (in a large flask) with cryst. Na,C03-f ioH,0, add about 15 grms. NaC,H.,0,. dilute to about 2 litres, heat to boiling, and filter hot. Wash well. See Note 11 to Analysis No. 21. Precipitate b. Fe.-,0:.+Al,0..;as basic acetates; also P20,.' Washj dissolve in strong IIC1, and divide into two unequal portions. Solution £'. -5. To determine P„( )r> proceed ex- actly as with ''■So- lution gx" in A- nalysis No. 21. Solution b2. -3. To determine Al,(.)„ proceed ex- actly as with "So- lution g2" in A- nalysis No. 21. Filtrate b. Mn, Ca, Mg. Proceed exactly as in "Filtrate g," in Analysis No. 21, Scheme II. Omit, however, the treatment with Br. if Mn is known to be wanting. Note. — If the slag contains much manganese, the solution of the fused mass will be strongly colored green from the formation of sodium and potassium manganates; on boiling this solution it becomes of a violet colorin accordance with the following reaction : 3K.,Mn04 4-311,0 = MnOJFO + K.,Mn,Ofl-f 4KHO. On adding 1IC1 to the permanganate solution it loses its color owing to following reactions: K2Mn,Os-fSlICl=2(Mn02II20)4-2KC14-2lI,0-r-6Cl, and MnOsII!0+4lICl=SlnCl!1+3H!10+2Cl. C\ Analysis No. 20.—Hematite. Q\ Determination of Fe, Si02, S, and P.—Pulverize very finely, and weigh out on a watch-glass exactly 5 grms., mix on glazed paper with 25 grms. pure Na,CO„-|-- grms. NaNO> and fuse in 2 oz. platinum crucible. (Consult Note 2, Analysts No. 21.). Cool suddenly, place in a casserole, and treat with boiling water until thoroughly disintegrated. Remove the crucible {Note 3, Analysis 21), and add carefully excess of HCl. Evapo- rate to dryness on water-bath, expel HCl in air-bath at iio°-ii5° C. Add HCl, digest, dilute, and filter. Residue a. Filtrate a. Si02. Dry, ignite Dilute to 500 c.c., and divide into 3 portions. thoroughly, and weigh. If not white after Solution a1. Solution a"1. Solution a3. ignition repeat the fu-sion and treat as be- 100 c.c. 100 c.c. 300 c.c. fore. Determine S as BaS04 in Add excess of NH4HO, Add NH,HO in excess, the usual manner. wash to remove NH4C1, do and proceed for determina- The filtrate from BaS04 not bring on filter, dissolve tion of P exactly as with may be reserved for dupli- in H„S04, reduce and deter- "solution g" in Analysis cating the Fe. mine Fe by K0Mn,U,. No. 21. See Note 18, Analysis No. 21. Quick Method for the Determination of Iron only.—Sample, pulverize, fuse 1 grm. Na.,C(>.,Xi grm. NaN03 about 20 minutes. Plunge crucible while hot into cold water in a casserole; boil, and after removing crucible neutralize carefully (CO, escapes) with cone. H.,S(>4; add excess of acid, filtrate, if much remains undis- solved, dilute to 500 c.c.. divide in halves, reduce with amalgamated zinc and platinum foil, and titrate with K,Mn„<) as usual. See for details of the latter steps, Notes to Analysis No. 21. Sc/ten/e II G > Analysis No. 21.—Titaniferous Iron Ore. Scheme II.* Prepare an average sample for analysis. {Note i.) Pulverize in an agate mortar to an impalpable powder. Make a qualitative examination for H.,0 — TiO, — Cu — As and Cr. If Cu —As or Cr are present, see Scheme I. To be determined: Ti02 — SiO,— Fe — AlsO, — Mn — CaO — MgO — S — P — H2O. Weigh out exactly 5 grammes, mix with 20 to 30 grammes Na,C03 and 2 to 5 grammes NaNO.., and fuse in a platinum crucible. [Note 2.) Cool suddenly, place in a casserole and treat with boiling water until the mass is thoroughly disintegrated. {Note 3.) Filter and wash with hot water. {Note 4 and Fres., § 160, S, a.) 1. "Water Solution. It must be perfectly clear but may be colored, and may contain SiO, — SO, — P2On — and A1203- Add carefully an excess of HCl. evaporate on water-bath to dryness, heat in an air-bath at 100" C. to 115° C. till odor of HCl is no longer perceptible. {Note 5.) Moisten residue with HCl, add water, digest, filter, and wash hot. Residue a. SiO, To be added to and re-fused with Residue b. Filtrate a. Dilute to 500 c.c. and divide into three portions. Solution a' —300 c.c. Solution a2 — 100 c.c. Put into a large flask to ! Add BaCl, and determine be afterwards combined with ' HSO, as BaSO, (Note 8 Filtrate/. | and Fres.. § 132.) Solution a3— 100 c.c. Add to Solution b2, as a little Fe often enters the water solution. •Scheme I may be found in A merican Chemist Vol. I, p. 323. Both schemes are modifications of one originally drawn up by Dr. C. F. Chandler. (See preface to this work.) CA 2. Insoluble Residue. It may contain SiO —TiO —P2Or—Fe20—A1,03—Mn„0 —CaO—MgO (and Pt from the crucible). - Dry the residue on the filter, transfer to a casserole, burn the filter and add the ashes. Moisten with water, add cone. HCl, evaporate to dryness, heat till HCl is expelled; add cone. HCl, then water. {Note 9.) Digest with occasional stirring, filter, and wash. {Fres., § 140.) ON 4^ Residue b. Contains Si02—TiO,, etc. Combine with Residue a, fuse with 5 parts Na,COs, remove fused mass "from crucible with hot water, acid- ulate with HCl, evaporate to dryness not above ioo° C. {Fres., § 140, II, a.) Add HCl and boiling water, filter and wash. Residue c. Dry on fun- nel, fuse with 6 parts KHS04; dissolve in about 300 c.c. cold wa- ter, filter and wash cold. Filtrate c. Add this filtrate and washings to Filtrate b. Residue d. Dry, ig- nite and weigh as SiO,. Filtrate d. Dilute to 500 c.c. and divide into 3 portions. d\ d* and d3. Filtrate b or Hydrochloric Acid Solution. Combine with Filtrate c. Dilute to 500 c.c. and divide into 3 portions. Solution bx—-300 c.c. Saturate thoroughly with H,S gas and filter from the PtS„ and S. Filtrate e. Boil with KC10„ to oxidize FeO. Filtrate f. Cool, combine with Solutions < > > Solution dl 300 c.c. Add to I1titrate /■ Solution d1 100 c.c. Add to Solution b* Solution d< 100 c.c. Add to Solution b3 Solution gx x. Add NH4H0 in large excess, wash twice by decantation and re-dissolve inconc.HN03. Boil down to small bulk, add NH,N03 and 50 c. c. (XH4).,MoO., +HNO,). Warm and set aside 24 hours. Filter, test fil- trate, wash with tile diluted precipitant ('i and )i). Dis- solve ppt. in NH4HO in original beak- er, filter through same filter, add " magnesia mixture" and determine P,0, as usual. {Fres., § 134 I., 6, $.)(Com- parc Note 12.) Solution Add (NII,)IIO in excess to precipitate Fe.O+Al,- O..+P..O-" (+TiOa). Boil till all free Nil. is expelled, filter, wash thoroughly. dry, ignite and weigh. {Fres. § 105 and § 113.1, a, and Note 13.) From this weight deduct P-.0, found in gl, together with the Fe..O;; calcu- lated from A" and TiO, found in k; difference =A1,0, Precipi- tate h. Dis- solve in IIC1 on filter and wash. Boil, add Na,CO„ in ex- cess. boil, fil- ter and wash. Dry ig- nite and weigh as MnO, {Fres.. § 109, 1. a.) {Co m- P a r e Note 16.) Filtrate h Contains Ca and Mg. AddNHjHO XH4C1 and (NH,)X'„04, let stand 12 hours, filter and wash lot. Precipi- tate i. Dissolve p p t. in IIC1. re- precipi- tate with XlhllO filterand wash (add fil- trate to fit rate /.) Dry ppt., burn fil- ter sepa- rately, moisten with II,SO,in crucible and ignite. Weigh as CaS04. (Fres., §>ot,2,/.,a.) Filtrate i. Add NII.IIO and Xa,HPO,. let stand 12 hours, filter, wash,dry and ignite. Weigh as Mg,P„07. {Fres., § 104, 2.) Precipi- tate k Consists of TiO, Dry, ig- nite and weigh. If dark colored. fuse with 6 pts. KIIS()4. dissolve in cold water, filter and reprecip- itate by boiling. filter, wash, ig- nite and weigh again as TiO... {Fres., § See Sun- dry Sug- gestions, No. 4. Filtrate k. Expel the H,,S by boil- ing with KCK)::, concen- trate fil- ter, dilute to 500 c. c. and divide into 2 por- tions. Solution k\ Reduce the Fe.O by amal- gamated Zn and Pt foil and de- termine Fe volumet- ricallyby Margue- rite's process. (Fres., § H2, 2, a.) Solution k'K Treat in exactly the same way as solution kl and average the re- sults. ( Com- pare Note 18.) Special Determinatwi. Determine H,0 in 1 grm. of ore by direct weight. {Fres., § 36.) 66 QUANTITATIVE ANALYSIS. Notes to the Preceding Scheme. Note i. Sampling the ore.—Break up in an iron mortar forty or fifty pounds into pieces that will pass through a tin sieve with half-inch holes. Thoroughly mix the fine and coarse. Break up about ten pounds of average quality, so that it will pass through a tin sieve with quarter-inch holes. Mix well, take one pound, and pulverize in the iron mortar until it will pass through a brass sieve of 60 meshes to the linear inch. Mix well, take out about 50 grammes, pul- verize in agate mortar, pass through muslin bolting cloth, and put into a small bottle, tightly corked, for analysis and special determinations. It is yet necessary that every portion of this required for the main analysis or a special determination should be further pulverized, as needed, in an agate mortar, to an impalpable powder. Note 2. Preliminary fusion.—Thoroughly mix the ore and its fluxes on glazed paper, put about a third of the mixture in a two-ounce platinum crucible, the lower portion of whose interior surface has been previously lined with a thin layer of Na2COs, and heat over a common Bunsen burner with strong flame until the greatest violence of the effervescence has ceased. Then add and treat the two- thirds remaining successively and with the same precaution. Finally, heat strongly over the blast-lamp until the mass is in complete and quiet fusion, adding a little more Na2C03, should it not readily fuse. The time required for this fusion varies fron 30 to 50 minutes. Certain highly aluminiferous ores obstinately resist this method of attack; in such cases mix with the flux a known weight (two or three grammes) of chemically pure precipi- tated silica which has been strongly ignited just before weighing. The amount of silica added is afterwaids deducted from the total amount found in Residue d. notes to the precedixg scheme. 67 Note 3. Removal of the fused mass.—Let the crucible cool until just below red heat, then chill it suddenly by plunging it into cold water contained in a porcelain cas- serole, lay the crucible on its side and digest with boiling water. The fused mass will generally become detached from the crucible and come out in a cake. Then remove the crucible, wash it, treat in a small beaker with a little cone. HCl to remove any adhering particles of the mass, and add this solution to that of the Insoluble Residue (2). Should any portion of the fused mass, thicker than a film, obstinately resist solution in the hot water, it ought to be removed only by patience and long boiling ; and no attempt should be made either to dig it out or to dissolve it in HCl; lest by the formation of Aqua Rcgia or free CI (in the presence of NaN03, or Mn203) the crucible be attacked and injured. Note 5. Separation of Si02.—In order to render the Si02 entirely insoluble, it must be perfectly dehydrated. The evaporation should be carried to dryness, the residue heated until odors of HCl can no longer be detected, and the mass is hard and crumbly. Since the residue is to be re-fused with Residue b, the drying may be completed, at a temperature somewhat higher than ioo° C, in an air-bath. Note 8. Precipitation of BaS04.—Avoid the addition of a large excess of BaCl2 solution. Add only 5 c.c. at first, and then after complete subsidence of precipitate, add a few drops to determine if any H2S04 remains unprecipi- tated, etc. Then proceed as in Fres., § 132, I, 1. After decanting the clear supernatant liquid, boil the precipitate with water, allow to subside, decant, filter, and wash with hot water. These precautions are necessary to dissolve out any other salts of barium, which are always carried down on the first precipitation. If the precipitate of BaSO^ is dark colored after ignition, dissolve in the crucible in 68 quantitative analysis. hot cone. H2S04, pour into cold water, and collect the pre- cipitate as before. Note 9. Separation of Si02.—Evaporate as in Note 5. Then add HCl quite freely and warm for some time before adding any water, as the high heat may have produced anhydrous Fe203, forming an oxychloride which is very slow to dissolve, especially in dilute acid. Should the acid already added be too dilute, concentrate by evaporation, add cone. HCl, and digest at a moderate heat. Note n. Precipitation of the basic acetates.—Fil- trate f combined with Solutions a! and d1 must be very carefully neutralized with sodium carbonate. (If ammonium carbonate were used, bromide of nitrogen might form in Filtrateg.) To neutralize the greater portion of the acid use crystallized sodium carbonate, and complete the neu- tralization with a very dilute solution of the carbonate, add- ing it drop by drop, agitating to dissolve the precipitate, until the liquid assumes a deep mahogany-red color. If a permanent precipitate forms, add a little hydrochloric acid, and repeat as above. Then dilute the solution to about 1 litre for each gramme of the sesquioxide present, add about 20 grammes sodium acetate dissolved in a small quantity of water, and heat the whole to boiling. It is sufficient to boil from ten to fifteen minutes for the complete precipitation of the acetates. The filtering should be done rapidly on a ribbed filter, keeping the fluid hot, and disturbing the settled precipitate as little as possible. When available the Bunsen pump may here be used with advantage. After the supernatant fluid has been poured through the filter, throw on the precipitate and wash it with boiling water containing a little sodium acetate. Should any basic acetate separate upon concentrating the filtrate, add some sodium acetate, boil, filter, dissolve the precip- itate in HCl, and unite to the solution of the main body. notes to the preceding scheme. 69 In boiling Filtrate e with KC103 to oxidize FeO, be careful to decompose the whole of the chlorate by heat- ing with excess of HCl. Note 12. Determination of P2Os.—To remove the HCl in Solution g1 add NH4HO in large excess, wash the pre- cipitates of ferric hydrate and ferric phosphate by decanta- tion two or three times, and redissolve in hot cone. HNOs. Evaporate this solution down to small bulk (150 c.c. to 100 c.c), partially neutralize with NH4HO, and add about 50 c.c. of solution of ammonium molybdate in nitric acid. If the solution is very acid, ammonium nitrate is formed by the partial neutralization as above, otherwise add a small quantity of the salt. Warm the solution, do not boil, and let stand 24 hours or more. Then filter from the yellow granular precipitate of ammonium phospho-molybdate with- out bringing it all on the filter, and wash the precipitate with a solution prepared by mixing 100 parts of the precipi- tant with 20 parts of IIN03 (sp. gr.= i.2) and 80 parts of water. Dissolve the yellow precipitate by pouring a small quantity of dilute NH4HO through the filter into the original beaker, and determine the phosphoric acid in the *> ammoniacal solution by means of magnesia mixture (5 c.c.) in the usual manner. Magnesia mixture is preferably made with magnesium chloride. If the crystalline ammonio- magnesium phosphate falls mixed with flocculent magne- sium hydrate, add HCl until dissolved and reprecipitate with NH4HO. Reserve the filtrate and washings of the yellow precipi- tate, and test for phosphoric acid by adding a little more of the ammonium molybdate solution, heating and allowing to stand 12 hours. If a yellow precipitate forms, pour through a separate filter, dissolve in dilute NH4HO and add to the ammoniacal solution. If the yellow precipitate first obtained was not suf- 70 quantitative analysis. ficiently washed, a red residue of oxide of iron may remain on the filter, in which case pour dilute HNO, upon it, allow it to pass into the ammoniacal solution, acidulate that with HN03, warm, add more of the precipitant, and set aside as before; filter and wash several times with the diluted precipitant, then dissolve the precipitate on the filter and that adhering to the beaker in as little dilute NH4HO as possible. The yellow granular precipitate of ammonium phospho- molybdate is not sufficiently constant in composition to admit of directly weighing it in exact analysis ; it is there- fore dissolved in NH4HO and the phosphoric acid thrown down with magnesia mixture as just detailed. According to Nuntzinger's analysis, after drying at ioo° C, it contains 3.577 per cent. NH4HO 3.962 " p2o5 92.461 " Mo03 100.000 Lipowitz says the precipitate dried at 200 to 300 C. con- tains 3.607 per cent, of P,05, and Eggertz 3.7 to 3.8 per cent. P2Os. When dried at 1200 C, Sonnenschein found about 3 per cent. For properties of this precipitate see also Fres., § 93, i, foot-ncte. Consult also Finkener's paper in Bericht d. d. chem. Gcs XI, p. 1638 (1878), and Chem. News, XXXVIII, p. 63, (1878). Note 13. Washing of Fe2033H20.—Wash this precipi- tate by boiling up with water and decanting until the wash water shows very little alkaline reaction with litmus paper, and gives very little precipitate with solution of AgN03. Then transfer to filter, and wash thoroughly with boiling water. Note 16. Determination of Mn.—(Gibbs' process, Am. NOTES TO THE PRECEDING SCHEME. 71 your. Sci. [2] XLIV, p. 216.) To the HCl solution add NH4HO in excess and solution of Na,HP04 in large excess. Then add dilute H2S04 or HCl until the white precipitate redissolves, heat to boiling, and add NH4HO in excess. Digest near the boiling point about an hour, when the precipitate, at first white and gelatinous, becomes rose-colored and forms crystalline scales. Filter and wash with hot water. If tinged red, redissolve the precipitate in dilute HCl, and repeat the process. On ignition the pre- cipitate is converted into Mn2P207, a nearly white powder. If Zn is present, it must first be separated as in Scheme I, Am. Chem., Vol. I, p. 323. Note 18. Volumetric Determination of Fe.—Put Solution k', which must be completely free from the KC103 used to oxidize Filtrate k, into a wide-mouthed reduction bottle holding about 250 c. c. Carefully let down into the bottle a lump of amalgamated zinc, free from iron, and a strip of platinum foil resting upon it, add about 10 c. c. cone. H2S04, cover with a watch-glass and set aside over night. To ascertain if the reduction is complete test the solution with ammonium sulpho-cyanide, which should give only a trace of pink color. Then introduce into a flask holding about 200 c. c, and fitted with a Kronig valve, exactly 0.2 gramme iron piano- forte wire, add dilute H2S04, and heat until complete solution of iron. Cool the flask, pour and wash out the contents of the flask into a large beaker containing about 400 c. c. cold water, add a little concentrated H2S04 and titrate with a solution of K2Mn208 (13 grms. in 2 litres water) to determine its strength. Repeat, and average results. Now pour and wash out the contents of the reduction- bottle into a large beaker, add cone. H2S04, and titrate with the standard K2Mn208 as before. If the HCl was not 72 QUANTITATIVE analysis. properly removed from Solution b2 the dark brown-red ferric chloride formed will interfere with the end reaction of the permanganate. In such a case reprecipitate with NH4HO, wash thoroughly, and proceed as with Solution k1. Treat Solution Hl in exactly the same manner, and aver- age the results. Cf. Analysis No. 3, C. III. For method of repeating the titration in the same solu- tion, see Crookes' Select Methods, p. 74. Sundry Suggestions.—1. Solution a3 may be used for duplicating the determination of S, provided the absence of Fe is proved by the proper tests. Duplicate determina- tions of Ca and Mg can be made, if desired, in the filtrate from the precipitate formed by ammonium hydrate in Solution b2, provided this precipitate be thoroughly washed. 2. Duplicate determinations of Ti and of Fe can be made in Solution bl; the Fe can also be estimated volu- metrically by dissolving in acid the weighed precipitate resulting from the treatment of Solution g2. In the latter case, however, the presence of Ti02 will impair the results. 3. The purity of the Si02 obtained in Residue d may be tested, after weighing, by heating with fluoride of ammon- ium and concentrated sulphuric acid in a platinum crucible, whereby all the Si02 is expelled and is determined by the loss in weight, the residue being Ti02 probably colored by Fe. 4. In fusing Residue c or Precipitate k, hydro-sodium sulphate may be substituted for KHS04, but since the for- mer contains water of crystallization it should be heated until the water is expelled before using in fusions. In either case avoid expelling the whole of the H2S04, or if the mass is heated to redness, partially cool, add cone. H2S04 and heat again at a lower temperature. In this notes to the preceding sciifme. jt, way the Ti02 will be held in solution by the excess of acid, and the resulting acid sulphate will dissolve out readily. For Special Determinations see Notes to Scheme I in American Chemist, Vol. I, pp. 323 et seq. Reactions.—A full discussion of the many and complex reactions which take place in the preceding scheme for the analysis of iron ores is superfluous. Wc add a few remarks and equations which may serve to throw light upon some points. A.—The action of potassium permanganate on ferrous sulphate has already been formulated in connection with the notes to Analysis No. 3. This action, however, may be regarded as taking place in two stages, as follows: ist stage. 2KMn04+H2S04=K2S04+2HMn04. 2d stage. 2HMn04+7H2S04+ioFeS04=2MnS04. +5(Fe2(S04)3)+8H20. Solution b2 is treated with excess of NH4HO and the precipitate dissolved in H2S04 in order to remove the larger part of the HCl which might vitiate the results of the titration as indicated in Note 18. The presence of HCl is injurious also because it exerts a reducing action on the permanganate as shown in the equations following: 2HMn04+i4HCl=2MnCl2+8H20+ioCl, and 2FeS04+H2S04+2Cl=Fe2(S04)3+2lICl. B.—When KC103 is employed in acid solution as an oxidizing agent (as in the case of Filtrate e), the reaction which takes place depends upon the acid used and partly upon the strength of said acid. Concentrated sulphuric acid is said to act thus : 6KC103+3H2S04=2HC104+2C1204+3K2S04+2H20 and nitric acid thus : 74 quantitative analysis. 8KC103 + 6HN03 = 2KC104 + 6KN03 + 6C1 -f 13O + 3H20. The action of hydrochloric acid on potassium chlorate is variously formulated; Bottger gives the equation (1) and Odling (2): (1) 2KC103+6HC1=2KC1+C1203+4C1+3H20. (2) 4KC103+i2HCl=4KCl+3C102+9Cl+6H20. In any of these cases the powerful oxidizing agency of KC103 is evident. Appendix to Analysis No. 21. A.—Method for the Estimation of Fe and Ti only. Sample, pulverize, fuse 1 grm. ore with 3 grms. NaFl-)-i2 grms. KHS04. Dissolve in large quantity of cold water; if there is any considerable residue re-fuse. Neutralize with Na2C03 until a slight precipitate forms, then add H2S04 until the ppt. redissolves and the liquid is slightly acid. Saturate with H2S gas, boil some hours, occa- sionally adding H2S water. Filter from the precipitate of Ti02+S, dry, ignite, and weigh, if dark colored re- fuse, etc. To filtrate add a little KC103, boil to oxidize H2S. Reduce the iron with amalgamated zinc and plat- inum foil, and titrate with K2Mn2Os as usual. As a result nf the fusion we have 4NaFl+Si02+4H2S04=4NaHS04+SiFl4-f2H20. B.—Flight's Method for the Separation of Iron, Alumina and Phosphoric Acid. {Journal of Chemical Society (2). XIII., 59J, 1S75. The solution of the three substances named must contain but little free hydrochloric acid. Boil the solution two or three hours with an excess of sodium hyposulphite, and filter. Wash thoroughly. Filtrate a. Contains all the iron and some of the P..O-. (If but a small amount of P„0- is present in the solution, this filtrate will contain no P„0- and may be rejected after careful testing.) Add XI^IIS saturated with H2S and warm. Filter quickly, wash with II,S water containing a few drops of Nil CI. Precipitate a. Contains all the Al.,0, and most of the P..O,.* Dissolve in HCl. add enough NallO to'cdmpletelv redissolve the precipitate formed and throw down P..O, with excess of BaCl,. Do not heat, but let stand a few hours covered. Wash with dilute XallO. Precipitate b. FeS. Dissolve in HCl. oxidize with IIXO, pre- cipitate with Nil,110 and determine as usual. Filtrate b. P„05. Reserve add to Filtrate d. Precipitate c. Dissolve the BaP,0, in IIC1, add slight excess of II.SO, boil and filter. Filtrate d. Combine with Fil- trate b and determine P..O, with magnesia mixture in the usual manner. Filtrate c. Al.()., in alkaline so- lution. Acidify with HCl and determine Al,Os in the usual manner. * Flight states that the P,0.-, is carried down with the A1,03 completely when the solution contains less than 45 per cent. PoO.-,. Analysis No 22.—Pig Iron. To be determined: Iron, Combined Carbon, Graphite, Silicon, Sulphur, Phosphorus, and Manganese. A—Determination of Graphite, Silicon, Sulphur, Phosphorus and Manganese. (By F. A. Cairns.)—Place 10 grms. of fine borings in a flask of about two litres capacity, add 25 to 3^ grms. KC10:!, little by little, a few grms. at a time, pour in carefully and gradually concentrated HCl, using eventually about 300 c. c. Digest until the iron is completely dissolved, then pour contents of flask into a porcelain dish and evaporate to dryness on a water-bath. Moisten with HCl, add water, filter through a weighed filter, previously dried at ioo° C. ON Residue a. Grapkite and Silicon. Wash thoroughly and weigh on the filter after drying at 10 >' C. Then transfer to a platinum crucible and burn off the graphite; weigh the residue as SiO.,. See A'ote 2. If the residue contains iron, expel the SiO., by heat- ing with N1I4F1 and II.,SO and weigh again. Compare AA. or the Second Method. Filtrate a. Dilute to 1000 c. c. and divide into three portions as follows : Solution a1. 500 c. c. For determination of phosphorus proceed exactly as with Solution g1 of Analysis No. 21, Scheme II. Solution a2. 300 c. c. For determination of sul- phur partially neutralize with solution of Na„CO.,, and proceed as with Solution a2 of Analysis No. II. si, Scheme Solution a3. 200 c. c. For determination of manganese proceed exactly as with Filtrate /"and Filtrate g of Analysis No. 21, Scheme II. Sec Note 1. C > H H > H < > > NOTES TO THE PRECEDING SCHEME. TJ Note i.—Care must be taken in dissolving the pig-iron in HCI-I-KCIO3 not to add the oxidizing agent all at once, nor too rapidly, otherwise some of the iron may remain unoxi- dized. Should a small portion of ferrous chloride remain in the solution, the subsequent precipitation of the iron as basic acetate (as in Filtrate f Analysis No. 21) will be imperfect; instead of an orange red flocculent precipitate resembling ferric hydrate, the iron will fall as a brick-red pulverulent precipitate, (anhydrous ferric oxide ?) which has the property of running through niters. Note 2.—Si02 obtained in this manner, and dried at ioo° C, contains 6 per cent. H20, which is expelled on ignition, and must be deducted from graphite after the Si02 has been determined. According to Allen (see Chemical News, Vol. XXIX., p. 91, Feb., 1874) the Si of the pig-iron is converted by the action of dilute HCl into leucone, 3Si0.2H20. By fusing the mixture of leucone and graphite with KHO, the former goes into solution, and both may be estimated directly. AA.—Determination of Graphite and Silicon. Second Method. (Eggertz, Chem. News, XVIII., p. 232.—Mix 10 c.c. H2S04 with 50 c.c. H20, cool, add 5 grms. fine borings, boil half an hour, evaporate one-third and cool. The reaction is as follows : 2Fe4C-f-8H2S04=8FeSCYfC2H4+HI2. This equation, however, but imperfectly formulates the reaction, the S forming H2S and the P forming PH3. A large number of compounds of C and H are evolved in addition to the C2H4 of the equation; according to Dr. y8 QUANTITATIVE ANALYSIS. Hahn (Annalen der Chemie und Parmacie, Vol. 129, p. 57, 1864) they include the following : f Ethylene. C2H<. f CEnanthene, C7H14. Caprylene, C8H1B. Elaene, C0Htfi. Paramylene, C10H20. Cetylene, C](.H32. etc. etc. Gaseous. \ Propylene, C3Hf [Butylene, C4H.. ^^ Liauid. {Amylene, C5H10. z ICaproylene. C0H12. Next add 10 c. c. HN03 and boil 15 minutes. 6FeS04+8HN03=:2(Fe2(S04)3)+Fe2(N03)6+N202 +4H20. Evaporate on a water-bath until vapor ceases to come off and the mass is nearly dry. Add 75 c. c. H20-f-i3 c. c. HCl and boil 15 minutes; add more HCl if any Fe203 remains undissolved. Filter through a filter washed with HCl, dried and weighed; wash first with cold water until no more iron appears in wash- ings, then with boiling water containing 5 per cent. HNOs. Dry at ioo° C, and weigh the residue consisting of Si02-j- graphite. Ignite and weigh again; the loss in weight gives the amount of graphite. Lest the residue contain some- thing besides Si02 it is well to determine the latter by heating with NH4F1 and H2S04, which expels the Si02 in accordance with the following equation : 4NH4Fl+Si02+2H2S04=SiFl4+2(NH4)2S04+2H20. The loss in weight gives the amount of Si02; consult, however, Note 2 of A. AAA.—Graphite determination according to F. A. Cairns. Dissolve 5 grms. borings in dilute HCl, boil, filter, wash with hot water, then with KHO solution, then with boiling DETERMINATION OF TOTAL CARBON. 79 water, then with {a) alcohol, {b) ether and {c) hot water. Dry and transfer to flask and determine as in B. In this process the combined carbon goes off in volatile hydrocarbons, and graphite -(-Si02 together with certain liquid hydrocarbons, remain. The Si02 is removed by the KHO, the hydrocarbons dissolve out in the alcohol and the ether, while the latter is removed at last by boiling water. B.—Determination of Total Carbon. A. H. Elliott's modification of Roger's Process. See Journal of Chemical Society, London, May, 1869; also Cairns' article in Am. Chem., Vol. II, p. 140. To 2.5 grms. of borings add 50 c.c. of a neutral solution of CuS04, containing one part of sulphate to 5 parts of water; heat gently for 10 minutes; the iron dissolves; copper is precipitated, and the silica, graphite, and com- bined carbon remain: Fe+CuS04=Cu+FeS04. The cupric sulphate should be as neutral as possible, in order to avoid loss of combined carbon, in the form of volatile hydrocarbons, as shown in AA. Add 20 c.c. CuCl2 (1 part of chloride to 2 parts of water), with 50 c.c. strong HCl, and heat for some time nearly to boiling, until the copper dissolves : CuCl2-l-Cu=Cu2Cl2. Prepare an asbestus filter as follows : select a glass tube of about 3 to 4 cm. diameter, and 18 to 20 cm. in length. Draw out this tube to taper at one end, and place broken glass and asbestus, lightly packed, in the narrowed portion of the tube. (See Fres., § 229, 1, a, Fig. 100.) Filter the cuprous solution through the asbestus, wash thoroughly 8o quantitative analysis. with boiling water, and transfer contents of filter to a flask holding about 200 c.c. In making this transfer, the carbon, asbestus, and broken glass may be blown into the flask together, in order to use as little water as possible. Add to the contents of the flask about 3 grms. of Cr03, (or if this is not available, about 5 grms. K2Cr207), and arrange apparatus as in the determination of C02 by direct weight, Analysis No. 7, note 8, II (page 34). Avoid adding more water than absolutely necessary to transfer the carbon. Add 30 c.c. to 40 c.c. concentrated H2S04, little by little, shaking constantly, and closing cock of funnel-tube each time. Finally, heat gently to boiling, not allowing more than three bubbles of C02 gas to pass per second: 3C+4Cr03+6H2S04=3C02+2Cr2(S04)3+6H20. Boil one minute, attach guard tube of soda lime, and aspirate slowly, three bubbles per second. Weigh the soda-lime tube for amount of C02 absorbed, and calculate the amount of carbon. Note—The carbon separated from cast-iron by treatment with sulphate of copper contains H and O, and cannot therefore be determined by weighing directly. Schutzen- berger and Bourgeois assign to it the composition expressed by the formula C„3H20, and consider it related to graphitic acid. Bulletin de la Societe Chimique de Paris, Vol. 23, No. 9. BB.—Other Methods for determining Total Carbon. A great number of methods have been devised for deter- mining total carbon, some of which we will briefly outline, remarking, however, that the foregoing is entirely satis- factory. determination of total carbon. 81 i. Method of Alvargonzalez. See Am. Chem., Vol. V., p. 437.—Place 10 grms. of borings in a beaker and treat with a solution of cupric sulphate (40 grms. CuS04 in 200 200 c.c. H20), stirring until the reaction ceases. Add di- lute HN03 gradually, and let stand until the copper has dis- solved. Dilute the solution and filter through one of Roth- er's half filters (described in Chem. News, Jan. 30, 1874, P- S7)> wash thoroughly, and dry on funnel at ioo° C. Detach ppt. from filter carefully, place in a weighed cru- cible (throw away filter), dry at ioo° C, and weigh. Ignite and weigh again; the difference between two weighings gives total carbon. This method is not free from objections, but will answer when great accuracy is not indispensable, and speedy results are desirable. 2. Method employed by I. Lowthian Bell. See Chemical Phenomena of Iron Smelting, London, 1872.—Digest 3 grms. borings from 24 to 48 hours with a solution of CuS04 in excess, collect the spongy Cu-J-C-j-graphite on an asbestos filter, and burn the carbon in a stream of oxygen gas, as in the ultimate analysis of organic bodies collecting the C02 in KHO solution. Cf. Analysis No. 30. 3. Method of Regnault and Bromeis. See Crookes' Select Methods, p. 74.—Heat borings in a combustion tube with a mixture of plumbic chromate and KC103, collecting the C02 in KHO. 4. Methods for the liberation of Combined Carbon are also numerous. {a) Boussingault triturates the iron in a porcelain mor- tar with 15 to 20 parts of HgCl2 and sufficient water to make a thin paste : Fe+2HgCl2=FeCl2+Hg2Cl2. 82 quantitative analysis. Then dilute with 200-250 c.c. HCl and warm for an hour; filter from the Si02-(-C, wash and dry. Transfer to a platinum boat, and heat in a current of pure H, volatilizing the Hg2Cl2. Weigh the C, heat again in a current of O, burning off the C, and weigh again. (b) Weyl dissolves the pig-iron under the influence of a galvanic current. Attach a weighed piece of cast-iron to the positive pole of a Bunsen cell, and suspend it in dilute HCl. The iron dissolves, H being given off at the negative pole, and the carbon is separated. Weyl has also devised another method based upon the following reaction: Fe2+K2Cr207+7(H2S04)=Fe2(S04)3+Cr2(S04)3 +7H20+K2S04. See Crookes' Select Methods, p. 76. (c) McCreath's Method. See Engineering and Mining Journal, March 17, 1877. The author uses double chloride of ammonium and copper to dissolve out the iron, while the precipitated copper dissolves in excess of this reagent; he then oxidizes the carbon by means of Cr03 in an appar- atus somewhat similar to Elliott's, collecting the C02 in a Liebig potash-bulb. 5. Eggertz Colorimetric Method. See Crookes' Select Methods, pp. 81 to 84; also Britton's paper in Journal of the Franklin Institute, May, 1870. C. — Other Methods for the Determination of Sulphur and Phosphorus. 1. Eggertz's Method. See Chem. News, Vol. XVII, p. 207. determination of sulphur, etc. 85 A. Dissolve 10 grms. KC103 in 200 c.c. H20, place in a 500 c.c. flask, add 5 grms. fine borings, boil and add 60 c.c. HCl, little by little, boiling until the Fe dissolves: 4KC103+i2HCl=4KCl+3C102+9Cl+6H20, and 2Fe+C102+Cl+4HCl=Fe2Cl6+2H20. Evaporate, dry on water-bath to insure oxidation of sul- phur. Thorough dryness is unnecessary, since Si02 does not interfere in acid solution with the precipitation of BaS04. Then add 10 c.c. HCl-f-30 c.c. H20, and digest on water-bath until all the Fe2Cl6 is dissolved. Then add 20 c.c. H20, filter, and wash thoroughly. Add 2 c.c. of a saturated solution of BaCl2 (enough to precipitate the H2S04 from o. 1 grm. S); after cooling add 5 c.c. NH4HO, stir and let stand 24 hours. Filter, and wash by decanta- tion with cold water two or three times, and then tho- roughly with hot water. Dry, ignite, and weigh. If the precipitate shows traces of iron after ignition, purify by so- lution in H2S04. B. For the determination of phosphorus dissolve the pig-iron in the same manner, and dry at 1400 C ; some anhydrous Fe203 will remain with the Si02; add water, filter, fuse residue with a little KHS04, soften with H2S04, and dissolve in water. Filter from the Si02, and determine it as a check on the main analysis. Add filtrate to main one, and determine the P20s by means of ammonium molyb- date, as in Analysis No. 21. 2. Method of Dr. T. M. Drown. See Am. Chem., Vol. IV, p. 423- Treat 5 grms. of borings in a flask with HCl, and pass the H2S and PIT formed through a series of three bottles containing a solution of K2Mn2Os(i grm. to 200 c.c. H20). Avoid a very rapid evolution of the gas; when this ceases. 84 QUANTITATIVE ANALYSIS. aspirate for some time, and then pour the contents of the bottle into a beaker, rinse with water, and add sufficient HCl to decompose the K2Mn2Os. Filter the colorless so- lution, add BaCl2, to throw down the H2S04, and proceed as usual. 3. Method employed by J. Lowthian Bell. Dissolve in HCl as above, and pass the gases through a solution of potassic plumbate (lead nitrate super-saturated with KHO). Boil half an hour, or until the evolution of gas has ceased. Wash the PbS formed, oxidize it with HN03, and throw down the S as BaS04 by means of Ba(N03)2. Let stand 24 hours, collect on a filter, dry, ignite, and weigh. This method is said to give higher percentages of S than that of Eggertz. Compare Fres., § 229, 2. 4. Method of Arthur H. Elliott. See Am. Chem., Vol. I, page 376. 5. Method employed by Koninck and Dietz. See Prac- tical Manual of Chemical Analysis and Assaying applied to Iron. Translated by Robert Mallet. London, 1872. Dissolve 3 to 5 grms. borings in HCl in a flask connected with four bottles, the first a condenser, the three following containing solution of AgN03(i part of nitrate to 20 parta of water). Boil, and when gas ceases to evolve, aspirate Pour contents of flask on one filter, and wash the Ag2S, Wash out the flask and cleanse the ends of the tubes witn bromine water, and expel excess of Br by heat; the follow ing reaction ensues : Ag2S+8Br+4H20=H2S04+2AgBr+6HBr. The phosphide is also converted into phosphoric uric Filter from AgBr, and ppt. H2S04 with BaCl2 as u.snai. determination of iron manganese, etc. 85 6. Method of Boussfngault for determination of Phos- phorus. See Annates de Chimie et de Physique, June, 1875, and abstract in American Chemist, Vol. VI, p. 275. 7. For additional methods consult also papers by Alfred II. Allen, Chem. News, XXIX, p. 91, and paper by Hamilton, Chem. News, Vol. XXI, p. 147. Compare Crookes' Select Methods, pp. 84-89. D.—Determination of Iron Manganese, etc- The iron may be determined by difference or by Margue- rite's method, in which case dissolve 0.2 grms. of pig-iron in H2S04, and proceed as usual. It is advisable to use a rather dilute solution of K2Mn208 towards the close of the oxidation. For the determination of the bases of Groups II, III, and IV, dissolve 10 or 20 grms of pig-iron in HCl, remove the Si02 by drying thoroughly, and proceed as in Analysis No. 21. The manganese may be thrown down in the filtrate, from the basic acetate of iron by means of bromine, or in the absence of calcium, magnesium, etc., by hydrodisodic phos- phate. See Fres., § 109, 3, also § 229, 5. For other methods of estimating manganese see articles by Samuel Peters in Chem. News, Vol. XXXIII, p. 35, and by William Gal- braith, in CJiem. News, Vol, XXXIII, p. 47. See also paper by Charles H. Piesse in CJiem. News, Vol. XXIX., pp. 57 and no. For testimony as to the condition in which silicon exists in pig-iron, see paper by E. H. Morton, Chem. News, Vol. XXIX., p. 107. Analyses Nos. 23 and 24.—Arsenical Nickel Ore. May contain SiO., S, As, Sb, Pb, Cu, Fe, Al, Mn, Zn, Co, Ni, Cu, Mg, etc. To be determined: As, Ni, Co.—Pulverize very finely; heat 2 grms. (or 4, if a very poor ore) in a covered casserole with fuming HNO, until the ore is completely dissolved, except a little silica. Expel excess of acid on a water-bath, add 10 c.c. HCl, dilute to about 200 c.c., warm and filter. Consult article by Fresenius in Ant. Chem., Vol. IV, p. 289. 00 0> Residue a. SiO, PbS04. CaSOt, etc. Test with blowpipe for CoandNi. If found, f u s e with KHSO.,. and add wa- ter solution to Filtrate a. Filtrate a. Add a little Na2SO,, and heat, pass H,S through the warm liquid until saturated. See Fre<; S 12c . and § 127. 4, a. Let stand some hours, throw on small filter, and wash with weak 1-1,8 water. Precipitate b. As,8,. If much free S is mixed with the precipitate, dry, and exhaust with CS„. Otherwise treat moist pre- cipitate, filter and all, in a porcelain casserole with fuming IIN()3; expel ex- cess of acid on water-bath, then dilute to about 150 c.c, and throw down As2Or, with " magnesia mixture." Fres., § 127, 2, a. Let stand 12 hours Solution b. Boil with a little KC10.+5 c.c. cone. HCl, evaporate nearly to dryness add water, warm, and add NH,HO in excess. Wash well hot. Precipitate c. Fe203 3H20. Dissolve in HCl and re- precipitate with NII.HO. filter and add the filtrate to Filtrate c. Filtrate c. Combine with second filtrate from the iron and add 20 c.c. NH4IIO. The solution should not measure more than 250 c.c. Introduce platinum electrodes and start the galvanic batterv. (See Am. Chem.. Vol. VI, page 213.) Run battery all night, but take care to maintain an excess of NIIJIO. Wash the precipitated Co and Ni with water, alcohol, and weigh. To determine if precipitation is complete, test solution with NH HS. tO C > H H > < > > r1 in the cold. Filter through Test the pre- a weighed filter, collect fil-jcipitate of iron trate and washings sep-'for nickel. arately. Measure filtrate and test washings. Dry precipitate at io5> to no0 C and weigh, repeat to a constant weight. For every 16 c.c. of filtrate {not washings) add one mgm. to the weight of the pre- cipitate. See Fres.. § 92, c. Filtrate d. Boil down to smaller bulk, and test with electricity as above. Precipitate d. Dissolve in warm HCl. partly neutral- ize with KIIO, add a cone. sol. of KNO, in excess, acidulate with acetic acid and let stand 24 hours. Filter and wash with a solution of neutral KCTI3O2 (10 per cent. sol.), and afterwards with alcohol. See Fres.. §111,4. Filtrate e. Concentrate. add KN02 and let stand. If pre c i p i t a t e forms add to precipitate e. Precipitate e. Dissolve in HCl, neu- tralize with Nil,110, and add 10c.c. more NII.TIO. Throw down Co by the battery as before. Weigh. Weight of Co-f-Ni less weight of Co gives weight ofNi. Consult Revue Univer- selle des Mines, Vol. 32, P- 545- Notes. the actio —By the addition of sodium sulphite to Filtrate a we reduce the nitric acid and prepare the solution for n of ILS. The reaction is as follows: 3Na.,SO,+2lIN(\=3Na„S04+N„0„+H50, and prevents the action shown in this equation : 1N<) -3NII4IIS0,+2NO+NH4NO,+S7-f-4H2O. 10HJS+7II Consult article by Parnell, in Chem. News, Vol.' XXI^ p. 133 article by E. Donath in Chem. Ne-vs. Vol. XLI, p. 15. On determination of cobalt and nickel consult 00 88 QUANTITATIVE ANALYSIS. Analysis No. 25.—Guano. Consult Fres., Quant. Analysis §§ 233, 235, and 236; also article by F. A. Cairns, Am. Chem., Vol. I, p. 82. To be determined: Si02, CaO, MgO, Fe2Os, P205, S03, H20, NH3, total N, organic and volatile matter. A.—Determination of Moisture. Heat 1 grm. at ioo° C. until constant weight and loss= H20[+(NH4)2C03]. In cases where great accuracy is required, a correction for the (NH4)2C03 counted as water must here be made., Heat the substance in a U tube in a water-bath and aspirate, collecting the (NH4)2C03 in normal H2S04. Titrate with KHO as usual. Subtract (NH4)2C03 found from H20 [-[-(NH4)2C03] determined by heating at ioo° C. as above. B.—Organic and Volatile Matter. Determine loss by ignition in open crucible, and correct for H20, (C02) and (NH4)2C03). C.—Ammonia. Use Schlosing's method, Fres., § 99, 3, b. Mix the guano with milk of lime and place under bell-jar over a dish of normal H2S04. A large surface of acid in proportion to the guano solution is desirable. Let stand, cold, 48 hours or more, and titrate with normal KHO as in acidimetry. (Cf. Analysis No. 11.) D.—Total Nitrogen. Use Varrentrapp and Will's Method, as detailed in Fres., § 185. Heat the guano in a combustion tube with soda lime, converting it into NH3. Absorb the NH3 in a stand- ard solution of H2S04, aspirate and disconnect bulb. Add litmus and titrate with standard KHO. B-—Sulphuric Acid. Dissolve in hot HCl, filter and precipitate with BaCl2, or follow the Scheme F. P.—Scheme for determination of SiO„, A1203, Fe20;, CaO, MgO, and total P205. Dissolve 5 grms. of guano in HXO , evaporate to dryness, add HN03+H,0, boil and filter. Residue a. SiO, and silicates. Wash. dry. ignite, and weigh, o r fuse as in Analysis of dolomite. Filtrate a. Dilute filtrate and washings to 500 c.c, mix well, and divide into five unequal parts. 100 c. c. 50 c. c. Reserve for accidents. 50 c. c. Determine! Determine Determine IPSO, with the P.O. the P.O. in with a m-! duplicate. m o n i u m Cf. Note molybdate. 12 of Analy- as in Solu-\sis No. 21. ft on g1, | A ?i a Iy s is No. 21. BaCl, in the usual man- ner, if a du- plicate be desired. 250 c.c. Add 1 grm. iron wire dissolved in HCl-p-HNO,. Precipitate iron, etc., as basic acetates, as in Filtrate f, Analysis No. 21. Wash the ppt., dissolve in HCl. dilute to 250 c. c, and divide into four unequal parts. 50 c. c. Reserve for accidents. 50 c. c. Determine total Fe by means of K,Mn,Os. and deduct 20 per cent. fo r iron added. 50 c. c. I 100 c. c. Determine Determine the Fe i n'Al.,0., as in duplicate. 'Solution ^2, For details' Analysis see Analy- No. 21, and 5/5 No. 3. in calculat- ing allow for the iron added. 00 90 QUANTITATIVE ANALYSIS. Analysis No. 26. — Superphosphate of Lime. To be determined: Moisture, reduced (or reverted) P2Os, soluble P2Os and available P205. A.—Determination of Moisture. Dry 1 grm. at ioo° and weigh—loss of weight=moisture. B.—Determination of Total P2O5. Weigh out 1 grm. accurately, mix with 2 grm. KNOs and 4 grms. Na2C03, fuse in platinum crucible, dissolve in HN03, evaporate in a casserole to dryness (to dehydrate Si02-j-aq.), add water and filter. Wash thoroughly and dilute filtrate to 500 c.c.; take 50 c.c. of this solution (=0.1 grm. of superphosphate) and determine P205 with (NH4)2 Mo04 as usual. Consult Note 12, Analysis No. 21. C—Determination of Insoluble P2Os. Digest 1 grm. with about 400 c.c. of water in 8 to 10 different portions successively, rubbing the superphosphate with water in a porcelain mortar. Filter and treat residue (filter included) with about 50 c.c. solution of ammonium citrate containing 30 grm. of salt to 100 c.c. of Avater, and carefully neutralized if acid. Digest at about 7o°C. for 40 minutes or longer, filter and wash. Dry residue and fuse exactly as in B. Estimate the P2Os in same manner using 100 c.c. (=0.2 grm. of superphosphate) of the solution (500 c.c.) for each determination. D.—Determination of Reduced and Insoluble P2Os. Leach another sample (1 grm.) with water as in C (omitting the use of ammonium citrate), dry the residue and fuse as in B. Continue as in B, taking 150 c.c. of the solution for each determination. potable water. 91 E.—Calculation. The reduced P2Os is found by subtracting the P2Os in C from that in D. The soluble P2Os=B-D and the avail- able P2Os=B-C. Note.—Reduced or reverted P205 forms thus: Ca3P208-f-CaH4P208=2Ca2H2P208. Consult Bolleys Handbuch, pages 802-806. Analysis No. 27.—Potable Water. To be determined: K; Na; Mg; Ca; CI; S03; Si02; organic and volatile matter, total solids ; hardness (soap test) ; oxy- gen required to oxidize organic mat- ter (permanganate test). Quantity required, three to four gallons ; collect in clean demijohns. A-—Determination of Total Solids and Loss by Ignition. Measure out 250 c.c. of the water, evaporate to dryness on a water bath, in a weighed platinum dish of 100 c.c. ca- pacity. During the evaporation cover the dish with a paper screen. Dry in an air bath I20°-I30° C. and weigh. Weight of residue gives " Total Solids." Ignite gently over a Bunsen burner, moisten with a solution of C02 in distilled H20, dry on water-bath, heat in air-bath I20°-I30° C. as before and weigh; difference between second and first weights gives organic and volatile mat- ter, also called " Loss by Ignition." For further treatment of residue see F Compare Chapter II of Wanklyn's " Water Analysis," 3rd edition, 1874. 92 quantitative analysis. B.—Determination of SiOz, Fe203, A1203, CaO, MgO. Evaporate 4 to 6 litres of water (according to the proportion of total solids) to small bulk in porcelain dish. Add HCl, transfer to platinum dish, washing care- fully the porcelain dish, evaporate to dryness, filter from Si02 and follow scheme for Dolomite, Analysis No. 7. C—Determination of H2S04. Take 1 litre (or less) of the water, boil down to 200 c.c. with a few drops of HCl, and determine SO., as BaS04 in the usual manner. If the water contains sufficient H2S04 (as sulphates) to give a feeble precip- itate with BaCl2 before concentration, one-half or one- quarter litre will suffice. D.—Determination of CI. Test the water with AgN03 for CI, and if no cloud is formed evaporate 1 litre to small bulk; otherwise 25 to 50 c.c. suffice. Add a slightly acid solution of AgNOs, and proceed as usual. Second method. Determine the CI volumetrically by a standard solution of AgN03, using potassium chromate as an indicator. See Fres. § 141,1, b, «. E.—Determination of Na and K. Evaporate 6 litres to dryness in a large porcelain dish, finishing on a water bath. Boil the residue with dis- tilled water several times, filter into a platinum dish and wash. Add Ba(H0)2 to filtrate. Evaporate to dryness, heat to low redness, let cool, take up with water, add (NH4)2C03 and a little (NH4)C204, wash the precipitate, filter, add HCl to filtrate, evaporate to dryness, ignite and weigh. Dissolve in water and if not clear, filter, evaporate, dry, ignite cautiously, and weigh again. This potable water. 93 residue of NaCl-j-KCl must be perfectly white and sol- uble without residue in water. Determine the CI in the weighed NaCl+KCl and calculate the Na and K as in Fres. §197, a. Compare Wanklyu, $rd editioi, page 63. P.—To check determination of Na and K. Moisten the weighed " Total Solids" of A with dilute H2S04, dry and ignite with a little powdered (NH4)2C03 to constant weight. By deducting from this weight, calculated fo? one gallon, the combined weights of Si02, Fe203, A1203, CaO, MgO (the latter four reckoned as sul- phates), the weights of Na2S04 and K2S04 are obtained. G.—Dr. Clark's Soap Test. Consult Sutton's Volumetric Analysis, §83,10: or Wank- lyn's Water Analysis, 3rd edition, page 125. Principle.—Hard water, so called, destroys much soap before a lather is formed, owing to the formation of insol- uble salts, viz. : stearates, palmitates, and oleates of cal- cium and magnesium. Preparation of Soap Solutions.—Dissolve 10 grms. of good white Castile soap (which should contain about 12 per cent, of water) in 1 litre of alcohol 90 to 95 per cent. Let stand and siphon off from the residue. Label this solution "No. 1." Take of solution No. 1, ico c.c; of 56 per cent, alcohol, 65 c.c.; of distilled water, 75 c.c, and mix. Label this soap solution " No 2." Preparation of Standard Calcium Solution.—Dissolve 1 grm. of precipitated CaC03 in HCl, evaporate until neutral, take up with water and dilute to 1000 c.c. 1 c.c of this solution contains grm. 0.001 CaC03. Standardization of Soap Solution.—Fill a burette with soap Solution No. 2. Place 10 c.c. of calcium solution 94 quantitative analysis. in a glass stoppered bottle. Add it to 100 c.c. of distilled water, run in soap solution from the burette and shake well, and continue adding soap solution until a lather is formed of sufficient consistence to remain for five minutes on the surface of the water. Read burette and calculate. Repeat. In certain cases allowance should be made for the amount of soap solution destroyed by water itself; 100 c.c. destroys 0.8 c.c. soap solution. Performance of Analysis.—Same as above. Report mil- ligrammes per litre and grains per gallon of CaCOs. Example.—ioc.c. of the standard solution of chloride of calcium required 23 c.c. of soap solution— But 10 c.c. of CaCl2 solution is equivalent to .01 grm. of CaC03, hence c.c. used) ) .01 \ 1 c.c. V = 23 ) 3 grm. CaCOs And if 100 c.c. of water under examination require 33 c.c. of CaCl2 solution, we have 33X.00043X 10 = grms. per litre of CaC03. This gives .1419; and .1419X.058318 gives grains per gallon. For the factor .058318 consult I, Calculation of Results. H. Permanganate Test for Organic Matter. Principle.—Permanganate of potassium in solution oxi- dizes putrescible organic matter. Preparation of solution of permanganate. — Dissolve 0.320 grms. of permanganate in 1 litre of water. Dis- solve 0.7875 pure oxalic acid in 1 litre of water, weighing very accurately. Of this solution 1 cc=o.oooi grm. oxy a = .00043 grms. potable water. 95 gen. To standardize the permanganate, take 10 c.c. of oxalic acid solution ; dilute to ioo c.c. with distilled water, add 5 c.c. dilute H2S04, heat nearly to boiling and run in from a burette the permanganate solution. 10 c.c. of oxalic acid will require 12 to 15 c.c. permanganate. Cal- culate value of 1 c.c. of latter in milligrammes of oxygen. Testing water.—Take 100 c.c. potable water add H2S04, add standardized permanganate, little by little in the cold, until the water retains a pink tinges after one-half hour's standing. Report amount of oxygen required to oxidize organic matter. Example.—10 c.c. of standard solution of oxalic acid required 14 c.c. of solution of K2Mn208— But 10 c.c. of H2C204 solution is equivalent to 0.001 grms. of oxygen, hence c.c. usedl 1 1. mgm. 1 \ : 1. c.c. J-= > : a — .0713 mgms. 14. J J oxygen J And if 100 c.c. of water under examination required 0.8 c.c. of K2Mn2Os, we have 0.8X.0713X 10 = mgms. per litre of oxygen required to oxidize organic matter. This gives .5704 milligrammes and .5704X.058318 gives grains of oxygen per gallon. See I, Calculation of Results. I.—Calculation of Results. To convert grms. in a litre into grains in a gallon, multi- ply the number of milligrammes of each constituent by 0.058318; or use Dr. Waller's Table, published in Am. Chem., Vol. V, p. 278. Report results in two ways: the grains per gallon of uncombined constituents, viz., Si02, Fe203, A1203, CaO, MgO, Na20, K20, CI, S03, together with " Loss by Ignition " and " Total Solids;" and secondly 96 quantitative analysis. report the grains per gallon of the bases combined with acids in accordance with the following scheme. Combine " " Na as Na2 S04 " excess of CI " Mg Cl2 " S04 " Ca S04 " Mg " Mg C03 " Ca " Ca C03 " K " K2S04 " K " K CI " CI " Na CI The sum of the combined salts -f- "Loss by Ignition" should equal the " Total Solids " very nearly. Example, showing method of calculation.—A sample of potable water yielded on analysis the following results : CI .215 grains per gallon Na .291 « it n S03 •340 << M H CaO .804 (< a «« etc. etc. Begin by calculating the amount of Na required to saturate the CI found, thus : (1) |X1 : Na = f Amount 1 # f Amount of Na [of CI found./ ' [needed for the CI. .35-5 : 23 = 0-215 : w w = 0.139 grains. hence 0.215 -j- 0.139 = 0.354 grains NaCl. But the water contains .291 grains Na, hence we have .291 — .139 = .152 grains Na left over to combine with S03. POTABLE WATER. qj 0.152 grains Na corresponds however to 0.204 grains Na20 making then a proportion similar to (1) we have (2) f Na20 : S03 = f Amount j f Amount of SO, 1 ■ of Na20 ■ : \ needed remaining, j [ for the Na20. 62 : 80 = 0.204 : x x = 0.263 grains. • hence 0.204 + 0.263 = 0.467 grains Na2S04. But the water contains 0.340 grains S03 hence we have 0.340 — 0.263 = 0.077 grains S03 left over to combine with CaO. Accordingly we have the proportion (3) fSOs: CaO = fAmountof SOJ f Amount of CaO 1 [ remaining. J '[needed for the S03. J. 80 : 56 = 0.077 : y y = 0.0539 grains CaO, hence 0.077 -J- 0.0539 = o. 130 grains CaS04. Proceeding in like manner the CaO remaining is regarded as combined with C02. 0.804 — °-°539 = 0.7501 grains CaO ; and since. (4) J CaO : CaC03 = 0.7501 : z ~\ whence z = 1.34 grains CaC03. J Collecting the results of the calculation we have (thus far) the following figures for the constituents combined: NaCl = 0.354 grains per gallon. Na2S04 = 0.467 " CaS04 = 0.130 " CaC03 = 1.34 " " " etc., etc. 98 QUANTITATIVE ANALYSIS. The following will serve as a further example of the manner of reporting similar analyses. Analysis of Croton Water by Dr. C F. Chandler. Grains per gallon Soda...... 0.326 Potassa ...... 0.097 Lime ...... 0.988 Magnesia...... 0.524 Chlorine ...... 0.243 Sulphuric acid ..... 0.322 Silica ...... 0.621 Alumina and oxide of iron trace Carbonic acid (calculated) 2.604 Water in bicarbonates (calculated) . o.532 Organic and volatile matter 0.670 6.927 Less oxygen equivalent to the chlorine •054 Total 6.873 Thescacids and bases are probably combined as follows: Grains per gallon Chloride of sodium ..... 0.402 Sulphate of potassa . 0.179 Sulphate of soda 0.260 Sulphate of lime 0.158 Bicarbonate of lime . 2.670 Bicarbonate of magnesia . I-9I3 Silica ..... 0.621 Alumina and oxide of iron trace Organic matter 0.670 6.873 SPECIFIC GRAVITIES OF SOLIDS AND LIQUIDS. 99 Analyses No. 28 and No. 29. — Specific Gravities of Solids and Liquids. A—Sp. gr. of a solid by direct weight. Weight of solid in the air = w « « « « water = w1 w Sp. gr. =-------- w — w1 B.—Sp. gr. of a solid by the flask. Weight of solid = w " " flask -|- water — w1 " " " " " -|- solid = w" w Sp. gr. =--------------- (w -f- w1) — w" C—Sp. gr. of a body soluble in water. Weight of body in air = w " " " " oil = w1 Sjj. gr. of oil = a " " " water = I The liquid displaced being w — w1 = w" then a: 1 = w" : w111 w Sp. gr. =---- D.—gp, gr. 0f a body lighter than water and insoluble in it, e.g., Cork. Weight of cork in air = w " " lead " water = w1 " " " and cork in water = w" ioo quantitative analysis. SP- gr- — w/_w//+w E. — Sp. gr. of a Body lighter than Water and soluble in it. Weight of body in air = w " " " " naphtha = w' w—w' = w" Sp. gr. of naphtha = A " " " water = i A : w"= i : w'" SP- Sr- = ^77T P. — Determination of the Proportion of two Metals in an Alloy. Sp. gr. of the alloy = S Weight of the alloy = A Sp. gr. of one of the metals = s' Sp. gr. of the second metal = s" Weight of one metal = w' Weight of the second metal = w" w, = A(S'-s")s' (s'—s")S w" == A—w' For proofs of this formula, see Galloivays First Step in Chemistry, p. 74. Gr. — Sp. gr. of a liquid by the flask. Weight of flask = F " " and water = w " " " " liquid = w' organic analysis. ioi w/__ F Sp- gr. = ^zp H. — Sp. gr. of a Liquid by weighing a Substance in it. Weight of substance = w " " in liquid = w' Sp. gr. of the substance = A w : (w—w') = A : sp. gr. c (w—w') A or Sp. gr. = 1_____L__ w Analysis No. 30, 31, and 32. Organic Analysis. Introductory Notes. The analysis of organic bodies comprises two branches ; Proximate Analysis which deals with the separation of proximate principles of organic bodies without altering them, and Ultimate Analysis, by which the nature and quantity of the elements composing the organic bodies are determined. No systematic course of proximate analysis is possible in the present state of the science ; animal chemistry is in this respect more advanced than vegetable ; for a course of zoo-chemical analysis see article by Gorup-Besanez in the Ncues Handworterbuch der Chemie, I, 551, and compare Watt's Dictionary, I, 249. See also Heintz Lehrbuch der Zoochemie and Lehman's Physiological Chemistry. For general principles of proximate organic analysis, consult Dr. Albett B. Prescott's " Outlines of Proximate Organic Analysis" a most useful manual, and the only one of its kind. For special methods of analyzing organic bodies, especially of commercial articles, consult " Bolleys Hand- buch der Technisch-chemischen Untersuchungen" of which the second edition by Emil Kopp is most valuable. 102 QUANTITATIVE ANALYSIS. The method of conducting an ultimate analysis is suffi- ciently detailed in Fresenius'' System, § 171-189, yet the following summary may be of service in calling attention to the chief points. A. Determination of C, H, and O, in Sugar. Select a very pure well crystallized sample of sugar, rock- candy will do, but small crystals from a vacuum pan are better. Dry at ioo° C, in powder. Provide the following articles : — (1) The dried substance in a tared watch glass. (2) Combustion tube of hard glass drawn out as shown in Fres. § 174, cleaned and carefully dried. (3) Liebig potash bulb filled with a KHO solution of Sp. gr. 1.27, or a U-tube filled with soda-lime. (4) Chloride of Calcium tube ; that of the form described by Thorpe in his Quant. Chem. Analysis page 347, fig. 80 is advantageous. (5) Small U-tube containing potash-pumice in one limb and CaCl2 in the other. (6) Rubber tubing. (7) Fine wire for binding the tubing. (8) Good corks, free from holes, rolled and pressed. (9) Cupric oxide, granulated preferred, chemically pure, freshly ignited to remove organic matter and moisture, and contained in a corked holder. (10) A platinum boat to contain the substance, or if another process be followed, a mixing wire. (11) Combustion furnace. (12) If oxygen is to be employed, a cylinder of this gas and a system of drying U-tubes must be provided. organic analysis. 103 (13) Sundry articles, such as glazed paper, agate mortar, towel, asbestus, a ramrod for cleaning combustion tube. etc. Process of the Combustion. (a) Weigh the substance (sugar) and preserve in a des- iccator until ready for use ; weigh also the KHO bulb to- gether with the U-tube (5), CaCl2 tube. (b) Dry the combustion tube and fill with cupric oxide ; the substance may be inserted on a platinum boat if the combustion is to be conducted with oxygen, otherwise it must be intimately mixed with some powdered CuO in the agate mortar and transferred by the glazed paper to the combustion tube. Stir also with the iron mixer. Avoid introducing moisture. (c) Connect the apparatus, arranging it as shown in the cut on page 433 of Fresenius1 System. Test the joints by heating the air in that bulb of the KHO apparatus which is between the solution and the combustion tube ; drive out a few bubbles of air and let cool, if an unequal level of the solution is maintained, the joints are tight. (d) Conduct the ignition, heating gradually, and begin- ning at the end next to the CaCl2 tube ; do.not apply heat to the substance until several inches of CuO are red hot. Pass oxygen gas through the tube if that method is em- ployed. Fres. § 178. The combustion of sugar may be completed in about half an hour, other substances require more time, especially those rich in Carbon. (;•) Aspirate air, or pass oxygen through the apparatus slowly. (f) Disconnect the weighed tubes, cool and weigh. From the C02 and the H,,0 found, calculate the C and' the H respectively. The O is found by difference. 104 quantitative analysis. Theoretical Composition of Cane Sugar. C12 144 . . 42.11 H22 22 . . 6-43 Ou 176 . . 51.46 342 100.00 In the case of nitrogenous bodies introduce copper turn- ings or a spiral of sheet copper in the end of the combus- tion tube next to the absorption tubes ; the metallic copper at a red heat reduces any nitric oxide which may form, and the inert nitrogen passes through the absorption tubes without increasing their weight. See Fres. § 183.2. The difficulty of effecting a complete oxidation of the carbon in organic substances increases, other things being equal, with the percentage of carbon contained in the sub- stance ; the richer the substance in carbon, the smaller the amount should be taken for combustion. Moreover, it is desirable to graduate the quantity used, to prevent the for- mation of too large a quantity of carbonic anhydride to admit of complete absorption by the potash solution ; hence the following Table, used in Prof. A. W. Hoffman's Labo- ratory, University of Berlin, is of service in determining the amount of substance which may be conveniently em- ployed. Table showing amount of Substances to be used in Ultimate Analysis. Of substances containing 80 percent carbon take o.200grms. 75 < << f< 0.225 < 70 < « u 0.250 " 65 < « l< 0.275 " 60 < «< <( 0.300 " 55 ( u u 0.325 " determination of nitrogen. 105 Of substances containing 50 percent carbon take 0.350 grms. 45 if < c a 0-375 40 U i 1 a O.4OO 35 (( t i a O.425 30 CI i 1 it O.45O 25 a t < a 0-475 20 Ct i 1 a O.5OO C. — Determination of Nitrogen in Potassium Ferrocy- anide by Conversion into Ammonia. Method of Varrentrapp & Will. See Fres. § 185. Purify about 50 grms. of the commercial salt by recrys- tallization ; dry the crystals on filter paper and preserve in a desiccator. The crystallized salt contains 3 molecules of water. Principle: When organic substances are heated with hydroxides of the alkaline metals the carbon is oxidized by the oxygen of the hydroxide, and hydrogen is set free ; if, however, nitrogen is present it combines with the nascent hydrogen, forming ammonia. (For an exception, see D.) By conducting the operation in such a way as to complete the reaction, and collecting all the ammonia by absorption in acid of known strength, the amount of nitrogen is easily calculated. Requisites: The apparatus needed is, in general, the same as that used in determination of C and of H, but a somewhat shorter tube (40 cm.) may be used ; the am- monia is absorbed by normal sulphuric acid placed in pear- shaped bulbs of the form shown in Fig. 92, or Fig. 94, pages 443 and 445 of Fres. System. The substance used to oxidize the carbon is soda-lime, at present a commercial 106 QUANTITATIVE ANALYSIS. 4 article ; it should be heated in a porcelain dish to expel water and ammonia before using. Operation: Fill the combustion tube about one-third full of warm soda-lime and let it cool ; then mix this in an agate mortar with 0.2 to 0.4 grms. of the dry ferrocyanide of potassium, and introduce the mixture again into the tube ; rinse the mortar with a little soda-lime, and then fill the tube with the same nearly to the open end. Insert a small plug of asbestos loosely, attach the absorption bulb containing the sulphuric acid by a well-fitting cork, and place the tube in the combustion furnace. Begin to heat the tube at the end nearest the cork, and proceed gradu- ally towards the other end. The gas evolved should bubble quietly through the ab- sorption tube, and when it ceases tp pass break the tail- piece of the combustion tube, and aspirate gently through the whole apparatus. Detach the absorption tube, empty its contents into a beaker, rinse well, add a little litmus, or cochineal solu- tion, and determine, by means of normal KHO, the amount of acid remaining unneutralized by the ammonia. For details of this process see Analysis No. 12. Theoretical Composition of Potassium Ferrocyanide: CG......................17.1 Ne......................19.9 Fe......................13.3 K4......................37.0 3H20....................12.7 100.0 DETERMINATION OF NITROGEN. IO7 D. — Determination of N from the Volume. Dumas'1 method modified by Melsens, Cf. Fres. § 184. See also Watts' Dictionary, I. 242. When nitrogen exists in an organic substance in the form of 3n oxide, e. g. nitro-benzol C,;H5 (N02), Varrentrapp & Will's method cannot be employed because the oxides of nitrogen are not completely converted into ammonia on heating with soda lime. Dumas' method consists in heat- ing the substance with oxide of copper, and measuring the nitrogen evolved by collecting over mercury. The process originally devised by Dumas necessitated the use of an air- pump to exhaust the combustion tube, but this may be obviated by following Melsens, who introduces hydro- sodium carbonate into the tube which gives up carbonic anhydride on heating, and drives out "the nitrogen before it. For Melsen's process provide the following articles : (1) A combustion tube 70 cm. long. (2) Mercury trough. (3) Graduated cylinder. (4) Copper oxide. (5) Solution of potassium hydrate. (6) Hydrosodium carbonate. (7) Connecting tube. (8) Corks, asbestos, rubber tubing, etc. (9) Combustion furnace. In filling the combustion tube observe the following order: Insert, first, 15 cm. of hydrosodium carbonate, then 5 cm. of copper oxide, then 15 cm. of copper oxide mixed with the substance to be analyzed, next add about 28 cm. of copper oxide, insert a copper spiral 5 cm. long, and lastly a plug of asbestos in the remaining 2 cm. Insert cork with connecting tube, and arrange apparatus as shown in Fig. 91, page 441, of Fres. System. io8 QUANTITATIVE ANALYSIS. Conduct the operation as follows : Heat a portion of the NaHCOs until all the air is expelled ; test with a solution of KHO in an inverted test-tube ; then heat CuO to red- ness, arrange the graduated cylinder containing KHO solu- tion over mercury, and heat the mixed CuO and substance until gas ceases to come off; lastly, expel the nitrogen in the combustion tube by again heating the NaHC03, some of which must have been left undecomposed. (Oxalic acid may be substituted for the HNaCOs. See Thorpe, page 332.) Transfer the graduated cylinder to a vessel of water, hold it so that the level of the water within the cylinder and without is equal, then read off the volume of the gas in cubic centimeters, and simultaneously the tem- perature of the water and the height of the barometer. Calculation of Results. To obtain the weight of nitro- gen from its volume employ the following formula : Let V = Volume of N observed, expressed in cubic centi- meters. And t°= Temperature of the gas. " B = Height of the barometer expressed in millimeters. " f = Tension of aqueous vapor at the temperature t°, expressed in mm. of mercury. Then if W = weight of nitrogen we have : 1 B —f W = .0012566 V--------------- 1+.003671° 760 The constant 0.0012566 is the weight in grammes of 1 c. c. of N at o° C and 760 mm. The constant 0.00367 is the coefficient of expansion of gas. Example : In an analysis of Butyramide — C4HrO) H V N, the following data were obtained : ANALYSIS OF URINE. IO9 0.315 grms. of substance gave 43.9 c. c. N at t°=i7°l C and B = 753.2 mm. First look out in a table the value of/at i7°-3. {Fres. § 195, page 461.) We find (calculating for the tenths of a degree)/= 14.7. Now V = 43.9 c. c. B — f =75,3.2 mm. — 14.7=738.5 mm. And 1 + .00367 X t°= 1.0635. Substituting in equation : y T> ___ £ W = .0012566 V —:----^—o —-?— we have : D 1+.003671 760 „, .0012566x43.9x7385 ._ W =---- s * = 0.0504 grms. N. 1.0635x760 3 t & » , 0.0504 x 100 -__ . .. And —'L-1------= 16.00 per cent nitrogen. 0.315 Theoretical Composition of Bittyramide: C4..........55-2 H9.........10.3 O..........18.4 N..........16.1 100.0 Analysis No. 33. — Urine. For brief methods of analysis consult Dr. George B. Fowler's " Urine Analysis," Thudicum's " Manual of Chem- ical Physiology," pages 178-192, and Sutton's " Systematic Handbook of Volumetric Analysis," part vi. § 78. For figures of sedimentary deposits examine Ultzmann & Hof- mann's "Atlas der Physiologischen und Pathologischen Harnsedimente." (44 plates.) The following works may also be studied: Legg's " Guide to the Examination of Urine," Attfield's " Chem- no QUANTITATIVE ANALYSIS. istry," F. Hoppe-Seyler's " Handbuch der Physiol, and Pathol. Chem. Analyse," Neubauer & Vogel's " Anleitung zur Qualitative und Quantitative Analyse des Harns," Gorup Besanez' " Lehrbuch der Physiologischen Chemie," pages 576-580, Ultzmann & Hofmann's "Anleitung zur Untersuchung des Harns." Constituents of Urine. * Urine, the secretion of the kidneys, in a healthy individ- ual, is a clear, yellowish, fluorescent liquid of a peculiar odor, saline taste, with a mean sp. gr. 1.020. The follow- ing are its normal constituents : I. Water. — H20. 2. Inorganic Salts. — K, Na, NH, Ca, Mg, combined with HCl, H3P04, H2S04, C02, (HN03)) and Si02. 3. Nitrogenous crystalline bodies. — Urea, uric acid, hip- puric acid, creatine, creatinine, xanthine, (ammonia,) cystine. 4. Non-nitrogenous organic bodies. — Sugar, lactic, succinic, oxalic, formic, malic, and phenylic acids, all in small quantities. 5. Pigments. — Urochrome, urohaematin. 6. Albumenoid matters. 7. Matters derived directly from the food. Besides these, urine may contain, under varying cir- cumstances, as in disease, a large number of 8. Abnormal constituents.— Blood, pus, mucus, albumen fibrin, casein, fats, cholesterin, leucine, tyrosine, allan- toic taurine, biliary pigments, indigo-blue, melanin, glucose, inosite, acetone, butyric acid, benzoic acid, oxaluric acid, taurocholic acid, glycocholic acid, and many others. (See Watts' Dictionary, vol. v. p. 962.) ANALYSIS OF URINE. I I I These substances do not occur simultaneously in all urine, and many of them but rarely. Only those com- monly determined are considered in the Scheme (page 112). Chemical Composition of Urine. (Dalton.) Healthy. — Numbers Approximate. Water.....................938.00 Urea......................30.00 Creatine.................... L25 Creatinine .................. 1.5° Urate of soda \ " potassia >............. i.8o " ammonia ' Coloring matter and mucus..........30 Bi-phosphate of soda Phosphate of soda " potassa \-.......... 12-45 " magnesia " lime Chlorides of sodium and potassium .... 7.80 Sulphates of soda and potassa....... 6.90 1000.00 Morbid urine may contain, also: Albumen, (Bright's disease.) Sugar, (Diabetes.) Bile, Excess of Urea, Oxalate of calcium. 112 QUANTITATIVE ANALYSIS. Action of Reagents on Urine. Boiling acid urine effects no change. Boiling alkaline urine makes it turbid if rich in earthy phosphates. HN03or HCl darkens the color, and throws down uric acid on standing. KHO or NH4HO throws down earthy phosphates. BaCl2 or PbA, in acidified urine, yield a white ppt. of sul- phates. AgN03 white ppt. of chlorides, also coloring matter and some organic substances. Murexid Test. — Collect some of the uric acid thrown down by HCl, remove supernatant liquid, add cone. HN03i and evaporate to dryness. When cold add a drop of NH4- HO. A purplish-crimson color shows formation of mur- exid (C8H N6Oe). Reactions of Urea. — Hg (N03)2 throws down a gelati- nous white ppt. containing COH4N2 .2HgO. Boiling with KHO converted into NHJiO ; test with Nessler reagent. HN03, nitrate of urea precipitates. NaCIO or NaBrO decomposes urea with evolution of N. Scheme for Analysis of Urine. 1. Physical Characters. (a) Odor. — Certain peculiarities in odor indicate either nature of food or symptoms of disease. (b) Consistence.—Viscous or fluid. (c) Color.—When healthy, urine is amber-colored; when bilious, brown or greenish. (d) Specific Gravity. — By the urinometer, 10.15 to 1025 is marked H. S., signifying Healthy State. 40 c. makes a difference of about i° in the reading. ANALYSIS OF URINE. r 13 2. Test with Litmus Paper, and note whether acid or alkaline. 3. Pour a sample into a stop-cock funnel, and let stand 12 hours. If a deposit forms, filter, and examine the filtrate and sediment separately. Filtered urine leaves a scum of mucus. (For sediments, see Schemes, page 117 and 118.) 4. Determine Total Solids. Evaporate 4 to 6 c c, weighed, to dryness in a weighed dish. Dry at 115 c. (In- accurate). 5. Ash. Evaporate 100 c. c. urine and ignite residue. 6. Determination of Urea. CH4N20. A.—Liebigs Method. Principle: Mercuric nitrate added to a solution of urea gives a white, gelatinous ppt. containing 1 molecule urea, and 2HgO. (Absence of NaCl necessary.) Requirements: {a) Standard solution Hg (N03)2. {b) Baryta solution. {c) Carbonate of soda test paper. {a) Standard solution of mercuric nitrate. Dissolve 72 grms. pure dry HgO in strong HN03, (50 grms.,) evaporate until syrupy, and dilute to 1 litre. If a yellow ppt. is produced by dilution, too little acid is present. It must be evaporated down, fresh acid added, and again di- luted. 1 c. c. = 0.01 grm. urea. To test the strength of the mercuric nitrate dissolve 2 grms. cryst. urea in 100 c. c. water. 1 c. c. mercuric solution should equal 0.01 grm. urea. {b) Solution of Ba(N03)2+BaH202. Mix 1 part cold saturated solution Ba(N03)2 with 2 parts cold saturated solution BaH202, and add 3 parts distilled water. {c) Soda test paper. Dip a sheet white filter paper into cone. sol. Na2 (C03) and dry. U4 quantitative analysis. Process: Collect the urine passed during 24 hours, and measure carefully. Place 20 c. c. in a small beaker, add 20 c. c. barium solution, filter from the sulphates and phos- phates. Of the filtrate 20 c. c. (containing 10 c. c. urine) are measured off, a drop of AgNOy added to precipitate excess of chlorides, and then standard solution of mercuric nitrate is added until a drop of the mixed solutions gives a yellow stain (of mercuric hydrate) on the test paper. Byasson adds some of a solution of KHO (25 grms. to 1 litre water) from time to time to partly neutralize the acid set free. The solution must not be rendered alkaline, Calculation: Amount urine passed in 24 hours = A ; c. c. mercuric solution used = C ; each c. c. being equal Ax C to 0.01 grm. urea; then -----= grms. urea passed in 24 hours. Caution: The urine must be free from phosphoric and hippuric acids. Consult Caldwell's " Agricultural Analy- sis," page 220. Urine must contain 2 per cent. urea. Cf. Watts' Diet. vol. v. p. 967. B. — Daveys Method of Estimating Urea. Pour a small quantity of urine into a graduated glass tube one-third full of mercury. Fill the tube with a solu- tion of sodic hypochlorite, close tube, and invert quickly over a saturated solution of NaCl. Let stand several hours while the following reaction ensues : CH4N20+3(NaC10)=C02+2H20 + 3NaCl+N2 Read off the quantity of N. 1.549 cubic inches of N at 6o° Fah. and 30" bar. = i grain urea. Method inaccurate since ammonia, uric acid, &c, are likewise decomposed. ANALYSIS OF URINE. "5 C. — Heintz and Ragskys Method. First determine ammonia by precipitation with PtCl4. Heat 2 to 5 c. c. with equal vol. H2S04 in a covered cap- sule to i8o°-20o°. Cool, dilute with water, filter, and de- termine NH3 formed by PtCl4. Calculate both amounts for 100 c. c, and take the difference ; this multiplied by 0.13423 gives per cent, of urea. Results very accurate. D.—Apjohns Method. See "American Chemist," V. 431. Provide the following apparatus : (1) A glass tube 30 cm. long, subdivided into 30 equal parts, whose aggregate volume is 55 c. c. The end of the tube is drawn out like a Mohr's burette. (2) A wide-mouthed gas bottle of 60 c. c. capacity. (3) A test tube of 10 c. c. capacity, and long enough to be slightly inclined when introduced into the gas bottle. The principle of the process is based upon the following equation : 2(CON2H4) + 3(CaBr202)=3CaBr2+2C02+N4 To make the hypobromite solution take 100 grms. NaHO, 250 c. c. H20, and add 25 c. c. bromine ; agitate and set aside for use. Process : Into a glass cylinder containing water the tube (1) is depressed till the zero mark and surface of water coincide. 15 c. c. hypobromite solution (100 grms. NaHO, 250 c. c. H20, 25 c. c. Br) are placed in (2) and the test- tube containing the urine is introduced carefully to avoid spilling its contents. The flask is closed by a perforated n6 QUANTITATIVE analysis. stopper which is connected by tubing with the measuring tube. The urine is now mixed with the hypobromite, and the disengaged nitrogen is driven into the measuring tube. The tube is now levelled to relieve hydrostatic pressure, and the volume of nitrogen read off. Since 55 c. c. equal o. 15 grm. of urea, a single division corresponds to —— =0.005 grm" urea. (0.15 grm. urea gives 55 c.c. nitrogen at 6o° Fah. and 300 bar.) 7. Determination of Actual Ammonia. Take 20c.c. filtered urine and treat by Schlosing's method. The NH3 is expelled by milk of lime, and absorbed by standard acid, in the cold under a bell jar. For details see Fres. § 99, 3 b. p. 158. (Human urine contains 0.078 to 0.143 per cent.) v 8. Determination of Albumen. Measure urine passed in 24 hours. Drop 50 c. c, one c. c. at a time, into 1 ounce boiling distilled water in a porcelain dish. If the urine was alkaline add a drop of acetic acid, avoid excess. Allow the coagulated albumen to settle, filter through a weighed filter, and wash well. Dry at ioo° C, and weigh. 9. Determination of Sugar. Dilute urine 5 or 10 times, and apply Fehling's solution as in grape sugar. See Analysis No. 35, Raw Sugar. 10. Determination of Phosphoric Acid. To 50 c. c. filtered urine add 5 c. c. sodic acetate and titrate with uranic acetate. For details see Sutton's " Volumetric Analysis." 11. Determination of Uric Acid. — To 200 c. c. urine add 10 c. c. HCl, stand 48 hours in a cool place, determination of urine. 117 filter on a very small weighed filter. Wash-water should not exceed 30 c. c. If more is necessary add 0.045 rngm. uric acid for each c. c. additional. (Albumen must first be removed by coagulation.) Dry at ioo°c and weigh. 12. Tests for Bile. (1) Place a little urine on a white plate, add HN03. A peculiar play of colors — green, yellow, violet, &c. — occurs if coloring matter of bile is present. (2) Agitate concentrated urine with boiling ether. If bile is present the ether solution will be greenish-yellow. (3) Add baric acetate to urine, treat the ppt with alco- hol, decompose it with HCl, and evaporate the liquid to dryness. Water will dissolve out in the residue coloring matter of the bile. (4) Pettcnkofers Test.—Mix fluid with one-half vol. H2S04, avoiding rise of temperature ; add a little powdered cane sugar ; mix and add more H2S04. Liberation of cholalic acid produces a purplish-red coloration ; this gives a pecul- iar absorption spectrum. See Thudichum's " Manual." Scheme for analysis of Urinary Sediments. (Attfield.) Warm the sediment with the supernatant urine, and filter. INSOLUBLE. Phosphates, oxalate of calcium and uric acid. Warm with acetic acid, and filter. INSOLUBLE. Oxalate of calcium and uric acid, Warm with HCl, and filter. INSOLUBLE. Uric acid. Apply murexid test. SOLUBLE. Oxalate of cal- cium. May be pptd. by MI4HO. SOLUBLE. Phosphates. AddNH4HO, and exam- ine ppt. for P205, CaO and MgO. SOLUBLE. Urates of Ca, Na, and NH4.— chiefly of Na. They are re-depos- ited as the liquid cools, and if suffi- cient in quantity may be exam- ined for uric acid and bases by usual tests. Note. —Urates are often of a pink or red color, owing to the pig- ment purpurine. This is soluble in alcohol. Il8 QUANTITATIVE ANALYSIS. Scheme for Determination of Urinary Sediments by Chemi- cal Tests. (Attfield.) The sediment is white; warm with the supernatant urine and filter. Solution contains urates. Residue Treat with ammonia Solution | Residue contains Treat with cystine. I acetic acid Residue oxalate and oxalttrate of calcium. Solution. Add NH4 HO white ppt. of earthy phos- phates. The sediment is colored and crystalline uric acid. and amorphous easily soluble on heating urates. and amorphous, slowly solu- ble on heat- ing. Urates colored by purpurine. ■ Analysis No. 34. — Milk. A. — Determination of Water. Wash quartz sand thoroughly with HCl and water, and ignite. Put about one-quarter inch of this sand in a plati- num pan, weigh, and pour on 3 to 5 grms milk. Dry at ioo° C. to constant weight. B—Determination of Butter. Break up the cake from residue A and wash the butter out with ether into a weighed beaker, evaporate the ether and weigh the butter. C. — Determination of Sugar. Collect the residue from B on a dried and weighed filter, dry it at 100° C, boil it four or five times with fresh por- tions (150 c.c. each) of 80 per cent, alcohol, and dry the insoluble residue at 100^ C. and weigh on a tared filter. The loss of weight gives the sugar approximately. Or determine sugar as under grape sugar, Analysis No. 35. DETERMINATION OF SUGAR. 119 A convenient apparatus for the extraction of sugar is described by Prof. S. W. Johnson, in Am. J. of Sci. (3) xiii. page 196(1877). D. — Determination of total Won-volatile Matter. Evaporate 10 to 20 grms. milk to dryness, with the addition of a little acetic acid, and ignite the residue in a muffle furnace, at the lowest possible temperature. E. — Determination of Protein Compounds. Subtract the sum of the butter, sugar, and ash from the total dry substance, and the remainder is chiefly casein. For other methods, see "A Method for the Analysis of Milk," by E. H. von Baumhauer, Am. Chem., Vol. VII., 191. Analysis No. 35. — Raw Sugar. L12H22On A. — Determination of Moisture. Heaf a weighed amount of sugar at 1 io° until it no longer loses in weight. Loss = moisture. B.— Determination of Ash. Weigh off ten grms. in a platinum dish. Either burn the sugar direct, or add a few drops of cone. H2S04 and heat very cautiously in a gas muffle. Weigh the ash. The two methods do not give results at all concordant ; the latter is the French method, and the results are called " the salts," after subtracting one-ninth, but this is seldom correct, though the ash burns very white. C— Determination of Grape Sugar. C6HuOu, H20 (1) Qualitative reactions. Glucose is colored dark- 120 QUANTITATIVE ANALYSIS. brown when heated with a strong solution of sodic hy- drate. It dissolves in cold cone. H2S04 without being blackened. [Cane sugar blackens.] If a cone solution of glucose is mixed with cobaltic nitrate, and a small quantity of fused NaHO, the solution remains clear on being boiled ; if very concentrated it de- posits a light-brown ppt. [Cane sugar solutions similarly treated give a violet ppt., which turns green on standing]. BaH202 added to an alcoholic solution of glucose forms a white ppt. If a little caustic soda is added to a solution of glucose, and then drop by drop a dilute solution of CuS04, a deep- blue liquid forms ; after some time in the cold, but imme- diately if heated, a yellowish or red ppt. of hydrated cuprous oxide is deposited. yooVoo °f glucose may be easily de- tected ; 1,000-000 st^ gives a red tint to the solution. Cupric acetate is similarly reduced. Potassio-tartrate of copper acts likewise. (2) Quantitative estimation. 1 eq. glucose will reduce IO eq. of cupric oxide to cuprous oxide. Preparation of Fehlings Solution. {Fres., § 250.) Dissolve exactly 34.639 grms. pure dry CuS04 in about 200 c. c. water. In another vessel dissolve 173 grms. C. P. Rochelle salts (C4H4K Na06-f-4H20) in 480 c.c. pure sodi- um hydrate solution having a sp. gr. 1.14. Mix the solutions and dilute to exactly 1000 c. c. 10 c. c. of this solution contains 0.34639 grms. CuS04 and corre- sponds to 0.050 grms. anhydrous glucose. Keep in the dark. On boiling with four vols, of water, it should give no precipitate. DETERMINATION OF GRAPE SUGAR. 121 The solution of glucose should not contain more than \ per cent, glucose ; if stronger, dilute. Performance of Analysis: Run exactly 10 c.c. of the copper solution into a small flask, add 40 c.c. water, (or a dilute solution of NaHO,) heat to boiling and run into the solution the liquid con- taining the glucose, slowly and gradually, from an accurate burette. Continue until the last shade of bluish green disappears, and a small portion of liquid filtered, gives no reaction with H2S, nor with HC2H302 and K4Fe2Cy6. Calculation. Since we took 10 c. c, Fehling's solution, corresponding to 0.050 grms. anhydrous glucose, we read off the number of c. c. of glucose solution taken ; this shows us how much of the substance contains 50 grms. grape sugar. Example. — Used 9. 5 c. c. solution containing glucose : 9.5 : .05 = 100 : x If solution was diluted, then xXd=per cent, glucose. This method may be applied to cane sugar, by first con- verting it into grape sugar by boiling one to two hours with dilute H2S04 (1 part acid 5 parts water). This is not very accurate, owing to formation of caramel. Milk sugar reduces Fehling's solution direct, but in another propor- tion, 100 glucose = 134 milk sugar. D. — Determination of Crystalizable Cane Sugar. Weigh out x grms.* of sugar or syrup, add water so that the whole will form about 80 c. c. Dissolve and add for *The value of x depends upon the instrument employed. Instruc- tions usually accompany a saccharimeter. 122 QUANTITATIVE ANALYSIS. syrup 5 to 10 c. c. basic acetate of lead ; for raw sugar less ; for pure sugar, none. Dilute to 100 c. c. ; pour into a beaker, and add pulverized bone-black, and filter ; do not wash. Fill the tube of a Soleil or Dubosq Saccharimeter with this solution, perfectly full, insert the tube, and observe the transition tint. For details, see Atkinson's translation of Ganot's Physics, § 613. Cf. Fownes' Chem- istry, p. 84, and Watts' Diet. hi. 673-5. Analysis of a sample of Raw Sugar. Water, ... . 2.07 Ash,.......1.58 Grape Sugar,.....1.82 Cane Sugar,......86.00 Analysis No. 37.— Petroleum. For information as to the composition and refining of petroleum, the products which it yields by distillation, and the methods of testing kerosene, see Dr. C. F. Chandler's " Report on Petroleum Oil" in the " American Chemist," Vol. II. pp. 409, 446, and Vol. III. pp. 20 and 41. A.—Distillation of Petroleum. The method of examining crude petroleum for determi- nation of its commercial value, is not that of fractional distillation in its true, scientific sense, but consists in a process of distillation which separates the liquid into a certain number of al;quot parts, having determinable den- sities, and flashing points ; and the value of the sample depends upon the proportion of the light and heavy pro- ducts. The process of distillation is conducted as follows. Se- lect a tubulated retort of strong glass, free from flaws, and distillation of petroleum. 123 of about 500 c. c. capacity ; connect this with a Liebig's condenser, and arrange for distilling in the usual manner. Through the tubulus of the retort insert a thermometer. Provide ten glass cylinders of 50 to 75 c. c. in capacity, and mark each with a file, so as to show the volume occu- pied by 25 c. c. of liquid. These cylinders are to serve as recipients of the distillate. Pour 250 c. c. crude petroleum into the retort, and apply heat very gently at first, increasing gradually, and finally heating until the residue in the retort is coked. Collect 25 c. c. of the distillate in the first cylinder, and note the temperature indicated by the thermometer in the retort; collect the second 25 c. c. in another recipient, note also temperature, and continue in this manner, changing the recipient for every 25 c. c. until the whole liquid has dis- tilled over. B. — Examination of the Distillates. Determine the sp. gr. of each distillate by floating in it a small Baume' Hydrometer, note the color of each sam- ple, and determine its flashing point by means of Taglia- bue's "Open Tester," a figure and description of which are found on page 41, Vol. III. of the " American Chemist." To test the flashing point, proceed as follows : pour a small quantity of the sample to be examined into the open cup, which is surrounded by a vessel of water. Light the lamp beneath and apply heat very gradually ; the tempera- ture should not rise faster than two degrees a minute. The thermometer bulb should dip beneath the surface of the oil. From time to time test the inflammable vapors which arise from the surface of the oil, using a small flame, flitting it quickly across the surface, and noting simultane- ously the height of the thermometer at the moment of io-nition. Record results with each distillate. 124 quantitative analysis. Example. — The following report of an actual distilla- tion shows how the results may be reported. This distilla- tion was accompanied with the^ phenomena technically called "cracking," by which the heavier hydrocarbons split up into lighter ones. ,No;.of Color. fraction. i. Colorless, 2. Temperature Fahr. I42°-224° 224 -298 Sp. Gr. Beaume1. 64 60 Flashing F Fahr. 20° 48 3. Light yellow, 4-5-6. Yellow, 298 -404 404 -458 458 "532 532 " ? 55 5i 45 42 102 147 208 254 7 Dark yellow, 40 204 8. Deeper " 9. Green, 42 44 II4 82 10. Black, The tenth product was coke left in the retort. Fig. 6 shows the disposition of apparatus at the commencement ot the distillation ; so soon as the lighter products have passed over, the bulb tube a c must be removed and connection made with the condenser by a short bent tube. APPENDIX. TABLE I. THE ELEMENTS, THEIR SYMBOLS, AND ATOMIC . WEIGHTS. Naini'. Symbol. .1. , Atomic Weight. Name. Symbol. Atomic Weight. Aluminium . . . Al 27.4 Manganese . . . Mn 55- Antimony . Sb 122. .Mercury . HS 200. Arsenic As 75- Molybdenurr 1 Mo 96. Barium Ba 137- Nickel Ni 58.8 Bismuth . Bi 210. Nitrogen . N 14. Boron . . Bo 11. Osmium . Os 199-2 Bromine . Br 80. Oxygen . O 16. Cadmium . Cd 112. Palladium Pd 106.6 Caesium . Cs 133- Phosphorus P 3i- Calcium . Ca 4°- Platinum Pt 197.4 Carbon . . C 12. Potassium K 39-i Cerium Ce 92. Rhodium Rh 104.4 Chlorine . CI 35-5 Rubidium Rb 85.4 Chromium Cr 52.2 Ruthenium Ru 104.4 Cobalt . . Co 58.8, Selenium. Se 79-4 Columbium Cb 94- 1 Silicon Si 28. Copper. . Cu 63 4 Silver . . Ag 108. Didymium D 95- Sodium . Na =3- Erbium E 170.5 Strontium Sr 87.6 Fluorine . F 19. . Sulphur . S 32- Gallium Ga 69.9 j Tantalum Ta 182. Glueinurn Be 9.4 Tellurium Te 128. Gold . . Au 197- j Thallium Tl 204. Hydrogen . H 1. Thorium . Th 235- Indium ' !n 133-4 Tin . . Sn 118. Iodine . . 127. Titanium Ti 50. Iridium ! Ir 198. Tungsten W 184. Iron .... Fe 56. Uranium . U 240. Lanthanum . La 93-6 Vanadium V 51.2 Lead . . . Pb 207. Yttrium . . Y 61.7 Lithium . . Li 7- Zinc . . . ; Zn 65.2 Magnesium . Mg 24- ' Zirconium Zr 89.6 APPENDIX. TABLE II. PRECIPITATING VALUE OF COMMON REAGENTS. Solutions of reagents being prepared of the strength recommended by Fresenius (see Fres. Oual. Anal., § 17 to § 85, b, Johnson's edition of 1875), the amount of a reagent required for precipitation may be calculated from the following table : One cubic centimetre of Will precipitate Dilute sulphuric acid......0.231 grm. Ba. Barium chloride.......0.032 " SOj. Hydrodisodic phosphate .... 0.011 " MgO. Magnesia mixture.......0.024 " P-jOj Ammonium molybdate.....0.001 " P2O0. Ammonium oxalate......0.016 " CaO. Argentic nitrate.......0.010 "CI. TABLE III. DIAMETER OF FILTERS AND WEIGHTS OF FILTER ASHES; SWEDISH PAPER. Diameter. Weight of Ash. ilter No. Acid. Alkaline. I . . 70 mm. 0.0004 grm. O.OOI4 2 . . . I04 " 0.0007 " O.OO27 3 • • . 122 " 0.00 I 1 " O.OO43 4 • • • H7 " 0.0016 '< O.O062 APPENDIX. TRINITY COLLEGE. Hartford.. i 88 Report of Analysis of Determination of Grammes taken : Method of Analysis. Actual Calculated Theoretical Precipitates. Weighty. Constituents. Weights. Percentages. Percentages. Special Remarks. [This is a reduced fac-simile of the reporting blank, measuring S by 10 inches, de- scribed on page 17.J ERRATA. First table on page 96 should read as follows Combine K as K, S04 excess of K '• KC1 " >• CI •■ Na CI " Na » Na2 S04. u CI •• Mg CL " S04'- Ca S04. i( Ca '• Ca C03. Mg " Mg C03. Page 9, line 16, for Ag C read AgCl. Page 11. line 20, for Beispeilen read Beispielen. INDEX. Acidimetry, 45. Albumen, determination of, in urine, 116. Alkalies, determination of, in potable water, 92. in feldspar, estimation of, 56. Alkalimetry, 42. Alloys, determination of two metals in, 100. Alum, ammonia-iron, analysis of, 20. Alumina, iron and phosphoric acid, 75. Alvargonzalez, determination of total car- bon, 81. Ammonia-iron-alum, analysis of, 20. Ammonia, determination of, in guano, 88. Ammonio-magnesic phosphate, properties of, 19. Ammonium, gravimetric determination of, 20. phospho-molybdate, properties of, 70. Analysis, organic, 101. Analyses, calculations of, 15. reporting of, 17. Antimony, determination of, 51. Apjohn's method of estimating urea, 115. Arsenical nickel ore, analysis of, 86. Ash, estimation of, in coal, 37. Baric chloride, analysis of, 13. Barium, determination of, 14. sulphate, properties of, 18. Bell's determination of total carbon in pig- iron, 81. Bile, tests for, in urine, 117. Bleaching powder, constitution of, 47. reactions of, 48. valuation of, 49. Bronze, analysis of, 35. Butter, determination of, in milk, 118. Butyramide, estimation of nitrogen in, 107. Cairns' determination of graphite in pig-iron, 78. Calcium, determination of, 31. Calculation of results of analyses, 15. Calorific power of coal, 39. Cane sugar, analysis of, 101. determination of, 121. Carbon, estimation of, in coal, 39. total, determination of, in pig-iron, 79. ultimate determination of, in sugar, 102. Carbonic anhydride, determination by direct weight, 34. determination by loss, 33. Chandler's analysis of Croton Water, 98. Chloride of lime, valuation of, 49. Chlorimetry, 47. Chlorine, determination of, 13. determination of, in potable water, 92. Chromic iron ore, analysis of, 54. Clark's soap test for potable water, 93. Coal, proximate analysis of, 36. Cobalt, determination of, in nickel ore, 86. Combustions, process of conducting, 103. Copper, electrolytic estimation of, 35, 39. estimation of, in a silver coin, 29. pyrites, analysis of, 39. Davey's method of estimating urea, 114. Distillation of petroleum, 122. Dolomite, analysis of, 30. Drown's determination of sulphur in pig- iron, 83. Eggertz' determination of graphite in pig- iron, 77. determination of sulphur and phosphorus in pig-iron, 82. Elliott's determination of total carbon in pig-iron, 79. Fehling's solution, preparation of, 120. Feldspar, analysis of, 56. Ferrocyanide of potassium, determination of nitrogen in, 105. Flight's method of separating iron, alumina, and phosphoric acid, 75. Fusion of an iron ore, 66. 125 126 INDEX. Glucose, estimation of, 119. Grape sugar, determination of, 119. Graphite, determination of, in pig-iron, 76. Guano, analysis of, 88. Heintz and Ragsky's method of estimating urea, 115. Hematite, analysis of, 62. Hydrochloric acid, valuation of, 46. Hydrodisodic phosphate, analysis of, 27. Hydrogen, determination of, in sugar, 102. Iron and titanium, determination of, 74. basic acetate of, 53, 68. determination of, in ammonia-iron-alum, 21. determination of, in a titaniferous ore, 68, 7'. determination of, by precipitation, 22. determination of, in hematite, 62. ore, titaniferous, analysis of, 63. slag, analysis of, 60. volumetric determination of, 22, 71. Koninck and Dietz' determination of sulphur in pig-iron, 84. Lead, estimation of, in a silver coin, 29. Liebig's method of estimating urea, 113. Liquids, specific gravity of, 99. Litmus solution, preparation of, 42. Magnesic sulphate, analysis of, 18. Magnesium, separation from calcium, 30. Manganese, estimation of, 56. Gibbs' method of estimation, 70. Marguerite's method for determination of iron, 22. Melsens' determination of nitrogen, 107. Milk, analysis of, 1:8. Moisture, determination of, in coal, 36. Molybdenum, use of, in estimation of phos- phoric acid, 69. Nickel ore, arsenical, analysis of, 86. Nitrogen, determination of, by Varrentrapp and Will's method, 105. Melsens' determination of, 107. Normal solutions, 41. Organic analysis, xox. matter in potable water, 94. Pearl-ash, valuation of. 45. Penot's method for valuation of chloride of lime, 49. Permanganate of potassium, standardization of, 25. Petroleum, distillation of, 122. Phosphoric acid, determination of, 28. determination of, in guano, 89. determination of, by molybdenum, 69. Flight's method of separation from iron, 75- insoluble, determination of, in superphos- phates, 90. reduced, determination of, in superphos- phates, 90. Phosphorus, determination of, in pig iron, 76, 82. Pig-iron, analysis of, 76. Potassium chloride, analysis of, 26. ferrocyanide, determination of nitrogen in, 105. gravimetric estimation of, 26. permanganate, solution of, 22. Pyrolusite, analysis of, 56. Raw sugar, analyses of, 119. Reporting analyses, 17. Reverted phosphoric acid, determination of, 91. Salammoniac, action of nitric acid on, 32. SchlSsing's determination of ammonia, 88. Silica, determination of, in soluble silicates, 59- determination of, in slag, 61. separation of, from titanium, 64. Silicates, analysis of soluble, 59. Silver coin, analysis of, 29. Slag, analysis of iron, 60. Soap test for potable water, 93. Soda ash, valuation of, 44. Sodium, determination of, 27. Specific gravities of solids and liquids, 99. Standard solutions, 42. Sugar, determination of ash in raw sugar, 119. determination of, in milk, 118. ultimate analysis of, 101. Sulphur, determination of, in pig-iron, 82. estimation of, in coal, 37. Sulphuric acid, gravimetric determination of, 18. INDEX. 127 Sulphuric acid in potable water, determina- tion of, 92. Superphosphate of lime, analysis of, 90. Testing petroleum, 122. Tin, determination of, in type metal, 51. determination of, in bronze, 35. Titaniferous iron ore, analysis of, 63. Titanium, estimation of, in iron ore, 74. Titration, residual method of, 45. Type metal, analysis of, 31. Urea, determination of, Liebig's method, 113. Apjohn's method, 113. Davey's method, 114. Urinary sediments, scheme for analysis of, 117. Urine, analysis of, 109. composition of, in. Varrentrapp and Will's estimation of nitro- gen, 105. Vinegar, analysis of, 46. Volatile matter, estimation of, in coal, 37. Volumetric analysis, general notes on, 40. estimation of nitrogen, 107. Water analysis, calculation of results, 95. determination of, by direct weight, 28. determination of, by ignition, 15, 28. determination of, in milk, 118. potable, analysis of, 91. Weyl's determination of total carbon in pig- iron, 82. Zinc, determination of, in bronze, 36. ore, analysis of, 53. f-l- It u »■>* MMIl HNS �9999999999999999999999999999999999999999999