Subject to Revision. 
TRANSACTIONS OF THE AMERICAN INSTITUTE OF MINING ENGINEERS.] 
TILE IMPURITIES OF WATER. 
BY A. E. AND GEORGE H. CLAPP, PITTSBURGH, PA. 
(Buffalo Meeting, October, 1888.) 
rI HI8 paper constitutes in substance a part of a more elaborate 
chapter, accompanied with extended tables of analyses, prepared for 
the book of Mr. Fred. H. Whipple on “ Water Supply.” In ad- 
vance of that use of the material, however, it seemed appropriate to 
lay a portion of it before the Institute; and this opinion of the 
authors, the Council, by accepting the paper, has ratified. 
It may seem at first glance, nevertheless, that a paper dealing 
chiefly with this subject in its sanitary aspects, and only treating in 
a subordinate way of the one subject (boiler-scale) usually deemed 
to concern our professions, is somewhat out of place in our Trans- 
actions. But reflection will, we trust, correct this impression. In 
recent periods, and in continually increasing degree, the managers 
of mining and metallurgical operations, especially the latter, have 
found themselves charged with the care of large numbers of men ; 
and the sanitary conditions of such establishments have become an 
important factor in their technical and commercial success. A gen- 
eral survey of the organic as well as the inorganic impurities of 
water may be suggestive and useful to such ; and since the chemists 
at metallurgical works might easily, with slight guidance, and with- 
out extra expense to their employers, ascertain the sanitary condi- 
tions presented by the water-supply, this subject may well be laid 
before them. At the same time, it is not proposed that our Trans- 
actions shall be crowded, to the exclusion of more directly profes- 
sional material, with details of sanitary science. These must, of 
course, be sought in special treatises, or at the hands of expert 
specialists. 
To prove the importance of this subject, we need only point to 
the startling proofs, collected since the announcement of the germ- 
theory of disease, that a contaminated water-supply is the active 
agent in spreading numerous epidemics, for which such a cause was 
formerly unsuspected. 
1 2 
THE IMPURITIES OF WATER. 
There is, perhaps, no question which more severely taxes the re- 
sources of science than the determination of the fitness or unfitness 
of a water-supply. Not only must waters of bad taste or smell and 
carrying considerable amounts of foreign matter be rejected, but 
many waters not only agreeable to the taste, but colorless, odorless, 
and containing very little suspended matter, are often the abundant 
sources of disease. 
It has long been known that dissolved oxygen plays an important 
part in the purification of water; that the amount of oxygen con- 
tained in water carrying putrefiable organic matter is very low ; and 
that where oxygen is deficient, and organic contamination consider- 
able, fish and higher grades of animal life desert the water, while 
microscopic examination shows an abundance of the lower forms of 
vegetable and animal life, such as algae and infusoria. It has been 
further observed that common fish, such as sunfish and suckers, will 
live nearer the source of contamination than the higher-mettled 
salmon and bass. Practical data thus given by nature should go 
hand in hand with the chemical analysis of a water-supply; for the 
evidence of nature is based upon larger samples, and hence better 
averages, than the chemist can command for analysis. 
Color.—By reason of vegetable and peaty matter, many samples, 
especially of surface-waters, have a decided color; a yellowish-brown 
of various shades and degrees of intensity being the prevailing hue. 
Professor T. M. Drown has adopted a very satisfactory series of 
standards for comparison of these shades, by solutions containing 
the Nessler reagent with certain known amounts of ammonia, so 
that the degree of color can be expressed in terms of given amounts 
of Nesslerized ammonia. 
These colored waters are not necessarily unwholesome. On the 
contrary, while they are not as attractive for drinking, and nearly 
always show more or less albuminoid ammonia, they often contain 
very little free ammonia, and are sometimes quite wholesome and 
pure. 
Suspended Matter.—In the analysis of drinking-water, the char- 
acter of the suspended matter, and its capacity to settle, or, on the 
other hand, to remain in fine suspension, and be served to the con- 
sumer through the service-mains, should be the criterion as to the 
advisability of filtering before analysis. In general, the chemist 
should seek to include in his analysis whatever the consumer includes 
in the water he drinks. 
Odor.—The odor a water gives should be noted. Many waters THE IMPURITIES OF WATER. 
3 
have decided odors, some already formed from the gases dissolved 
in the water, and constantly given off from it, or easily liberated by 
shaking the water, and sometimes liable to be generated by chemical 
or other changes in the dissolved or suspended matter. The odors of 
waters may best be tested in a confined space, as by shaking a wide- 
mouthed gallon-bottle, half filled with the water, and immediately 
smelling the air in the bottle, which will be impregnated with the 
gases from the water. 
Some waters give a different odor when cold than when hot; and 
the odor of some is due entirely to the suspended matter, and can he 
entirely removed by filtration, while in others filtration does not 
affect the odor. 
Prof. Drown, in his paper on “The Odor and Color of Surface- 
Waters,” read before the New England Water-Works Association, 
in 1887, suggests a series of terms for describing the various odors 
of waters, which we believe to he good, and have adopted in our own 
practice. He says of them : 
“‘Earthy’ is the <xh>r of freshly-turned soil or of a moist hot-house; it often 
passes into ‘ musty.’ ‘Straw-like’ is the odor of moist straw ; I think no one could 
mistake it, or fail to recognize it; it is one of the most frequent odors met with in 
surface-waters ‘ Mouldy ’ is the odor of moist straw which has begun to decom- 
pose; there is nothing disagreeable suggested by it; it is also somewhat allied to 
earthy or loamy odor. ‘Mustiness’ is advanced mouldiness and verges on the dis- 
agreeable. It is the odor of damp, closed vaults. ‘Wooden’ is the odor of tubs 
with hot water; it suggests wash-day. ‘Disagreeable’ is a more difficult term to 
explain, first, because it is not easy to get agreement among different observers on 
this point, and secondly, because under it we include two classes of odors, namely 
those of growth and those of decay. Some aquatic plants and low animal organ- 
isms give off mal-odorous matters as the product of their normal growth, and all 
organisms are more or less mal-odorous in the process of decay. Now, it sometimes 
happens that these two odors cannot l>e sharply distinguished from one another; 
they are both unpleasant odors So in the absence of finer discrimination of odors, 
or the positive identification of the noxious plants or animals, there seems to be no 
other way than to include them under the head of ‘disagreeable.’ It is of interest 
to note in this connection, that the river waters rarely give, either hot or cold, these 
‘disagreeable’ odors. They are generally confined to the waters of lakes, ponds, and 
reservoirs, which have abundant vegetation and but little motion. River waters, 
even those of considerable organic impurity, give ‘straw-like’ and ‘mouldy’ odors, 
but the unpleasant, fishy, oily and rotting odors are, as far as my experience goes, 
generally absent. ‘Offensive’ is a term sufficiently characteristic, it is more than 
disagreeable and may be reserved for waters undergoing putrefaction change, or for 
those which contain considerable sewage. Of the odors of the waters at ordinary 
temperature, the most frequently recurring are ‘straw-like’ and ‘mouldy’ and 
‘disagreeable.’ When heated, the ‘ wooden,’ ‘earthy’ and ‘musty’ odors are apt 
to be developed.” 
“ To express degrees of intensity of odor I am in the habit of using the qualify- 4 
THE IMPURITIES OF WATER. 
ing terms ; ‘very faint,’ ‘faint,’ ‘distinct,’ ‘decided’ and ‘strong.’ A good deal of 
personal equation comes in here. What is ‘faint’ to one is ‘distinct’ to another 
and ‘ very faint’ to a third. Still there seems to be need of some degrees of com- 
parison of intensity of odors, and, at all events, the use of any set of terms by the 
same observer will give comparable results.” 
“ The origin of the odors of surface waters, when uncontaminated with sewage 
or other drainage, is clearly referable to the vegetable and peaty matters of the soil 
over and through which it flows, and to the vegetable and other growths in the water 
itself. 
Water Analyses.—Sanitary analyses are made(l) to discover, with 
regard to a given water, whether it contains any organic or in- 
organic poisons, or such an amount of earthy constituents as will 
make it deleterious for drinking and cooking; or (2) to determine 
its value as a mineral (medicinal) water. 
Commercial analyses are made to determine concerning a given 
water, (1) its applicability, for making steam ; (2) its hardness, or the 
facility with which it will “form a lather” necessary for washing; 
or (3) its adaptation to other manufacturing purposes than those 
mentioned above. 
The common impurities of water are held in suspension (organic 
matter, both living and dead, and silica, clay, or other materials 
which the water may have been in contact); or in solution (mineral 
salts and acids, and the products of the decomposition of organic 
matter from sewage or other contamination). 
The results of water-analyses are reported in grains per Imperial, 
or United States wine, gallon, or in parts per thousand, hundred- 
thousand, or million. The imperial gallon is reckoned as 277 cubic 
inches, or ten pounds, or 70,000 grains, and the United States, or 
wine, gallon, as 231 cubic inches, or 58,372 grains, of pure water, 
at 4 degrees C. 
Until quite recently, the standard method of reporting adopted by 
English and American chemists has been in grains per Imperial 
gallon ; but at a late meeting of the Chemical Section of the Amer- 
ican Association for the Advancement of Science, held in Buffalo, it 
was decided to report all water-analyses in parts per thousand, 
hundred-thousand and million, and circulars were sent to the different 
chemists throughout the country, asking their co-operation in estab- 
lishing this uniform practice. 
To chemists who have been using the old method, the transition 
will be simple, as the Imperial gallon of water weighs 70,000 grains; 
and by taking 70 cubic centimeters (70,000 milligrammes), of water THE IMPURITIES OF WATER. 
5 
for analysis, wo have a miniature gallon, in which the milligramme 
corresponds to the grain. 
Uniformity in reporting results of chemical analyses is of great 
advantage for comparison. It seems to some desirable to have a 
well-known volume in mind when looking over analyses. But 
“grains per gallon” does not ordinarily mean grains per U. S. 
standard, or wine, gallon, but grains per Imperial gallon (not a well- 
known volume to us), and moreover, parts per 100,000 can easily be 
converted into grains per gallon, if desired, by dividing the results 
by 10 and multiplying by 7. The practical usefulness in this in- 
stance, however, of the conception of the gallon as a unit-volume, is 
doubtful. The largest proportion of impurities found in any water 
used for potable or manufacturing purposes (except for making 
steam), is so small that the measure of volume is only comparative. 
For instance, 70 parts per 100,000, the greatest amount of impuri- 
ties that could ordinarily be allowed in potable water, only means 
7-100 of one per cent.; so that in practice the figures come to have 
significance, not in their relations to the unit-volume, but only by 
comparison with one another, or with certain standards. 
Sampling.—A sample of water taken for analysis should be at 
least one-half gallon, if practicable. It should be kept in a cool 
and dark place until examined, and where possible, the analysis 
should be commenced within a few days. (In case of necessity, if 
extreme care be taken, as small a quantity as 50 cubic centimeters, 
or two fluid-ounces, may suffice for analysis.) It should be collected 
in a perfectly clean glass-stoppered bottle,* which should be rinsed 
out with the water before finally taking the sample. To insure a 
fair average for such a t«!st, if the water be taken from a pump or 
faucet, it should be allowed to run some little time before collecting 
the sample. Samples should not be taken too near the shore of a 
pond or stream of water, if the average of the whole is desired. 
In collecting, the mouth of the bottle should be opened some 
little depth under the surface of the water, to avoid the entrance of 
any surface-scum. A note should also be made, whether there has 
been previous long drought or heavy rain, and what is the condition 
of the water-level, together with a statement as to the neighborhood 
of any probable source of contamination. 
* Although it is preferable to have a glass-stopper to the bottle, still a clean and 
new cork will answer, but a cork contaminated with any other substance or luted 
with any sort of paste, might seriously injure the water for analysis. 6 
THE IMPURITIES OF WATER. 
Sanitary Analyses.—The difference in the specific gravity of 
waters, due to their relative degrees of purity, is very slight; so 
slight that, between pure distilled water and water that is very bad 
and has over 200 parts per 100,000 of total solid residue, the dif- 
ference is in the fourth decimal place, and very close to the factor of 
error or variance in making specific-gravity tests. Hence no reliable 
tests can ordinarily be made in this way as to the comparative purity 
of samples of water. 
The impurities in suspension vary from practically nothing in 
pure spring-and deep lake-waters, to perhaps 500 parts per 100,000 
in the water of many rivers, after heavy freshets. 
In solution, some pure artesian well-waters, some spring-water, 
rain-water, etc., have as little as 5 parts per 100,000, while the 
analyses of sea-water, some lake and river waters, and of some deep 
wells, range far above this proportion. Sea-water contains about 
4100 parts. 
For sanitary purposes, it is necessary to analyze water for the 
presence of metallic, and, occasionally, of vegetable, poisons, min- 
eral acids, or septic poisons from contaminations of sewage. Such 
septic poisons cannot be separated, and their weight directly deter- 
mined by analysis ; for they never have a definite and exact chemi- 
cal composition, like metallic poisons. 
The presence of septic poisons in water is shown by an excess of 
nitrogenous matter, indicated by the amount of chlorine and of free 
and albuminoid ammonia in the solution ; the chlorine largely com- 
ing from the chlorides of soda and potash, which, with urea, are 
among the principal ingredients of ordinary urine. 
Ammonia is evolved as the result of the decomposition of nitro- 
genous organic matter. Its presence in water in the small amounts 
reported in the analyses, even of the foulest waters, is harmless; it 
is only as indicative of decomposing organic matter that it shows 
the poisonous nature of the water in which it is found in considera- 
ble proportions. 
Albuminoid ammonia is the term given to nitrogenous organic 
matter of such a character that it is converted into ammonia by let- 
ting the water-solution of it stand. 
In large cities it is estimated that 30 gallons of water per capita 
of population, on the average, flows through the service-mains daily. 
A very large portion of this reaches the sewers and constitutes the 
bulk of the sewage. As a simple calculation, based upon the nature 
and amount of the contaminating material, will show, the average THE IMPURITIES OF WATER. 
7 
sewage contains in 100,000 parts, about 10 parts of free ammonia, 
and from 0.01 to 0.06 parts of albuminoid ammonia. When the 
free ammonia exceeds 0.02 parts per 100,000 in water taken from a 
thickly populated district, it is a probable sign that the water consists 
of dilute sewage. In such cases, the water will also usually contain 
over 0.6 parts of chlorine for river-water, and over 0.8 parts of chlo- 
rine for deep well- or spring-waters. The presence of albuminoid am- 
monia (over 0.018 parts per 100,000) with but little free ammonia 
and chlorine, is generally an indication of vegetable contamination, 
injurious to health. A sample of water containing per 100,000 more 
than 0.7 parts of chlorine, together with more than 0.015 parts of free 
and albuminoid ammonia, or both, can he declared with a consider- 
able degree of certainty to contain decomposing nitrogenous organic 
matter which, either in itself or in the accompanying germs, contains 
septic poisons and will he dangerous to drink, although the char- 
acter of the organic contamination is so varied that no exact danger- 
limit can, with our present knowledge of these impurities, he posi- 
tively fixed. Not that the presence of chlorine, which is so often 
present in combination with sodium, as common salt, is dangerous 
in itself, or that minute amounts of free and albuminoid ammonia 
poison the water; hut that they are indications of the presence of 
septic poisons, which cannot he separated by themselves. 
“ Nesslerizing ” is a method discovered by the chemist Nessler, 
for determining the strength of dilute solutions of ammonia by com- 
paring the yellowish-brown color given to the ammonia-solution by 
the Nessler reagent,—an alkaline solution of iodide of potassium 
saturated with pcriodide of mercury,—the color being more or 
less intense, according to the proportion of ammonia present in the 
solution tested. In testing samples of water, they are first distilled, 
and the ammonia which is carried over in the distillate is then deter- 
mined by Nesslerizing. The ammonia found in the first distillate, 
before the addition of any reagents, is the free ammonia; the albu- 
minoid is distilled over after the addition of caustic potash and per- 
manganate of potash to oxidize the nitrogenous matter that is 
capable of producing ammonia on standing. It is called “albu- 
minoid ” ammonia, because albumen in water-solution, when treated 
as described above, yields ammonia. 
The free ammonia represents the amount of change or complete 
decomposition of nitrogenous matter which has already taken place 
in the water; the albuminoid ammonia, the amount of change of 8 
THE IMPURITIES OF WATER. 
which the water is still capable by reason of the presence of nitrog- 
enous matter. 
Complete oxidation of animal or other nitrogenous matter will 
result in the formation of nitric and carbonic acids, which, in the 
presence of alkalies or alkaline earths, will form nitrates and carbo- 
nates, comparatively harmless in themselves. 
The presence of nitrites and of ammonia shows intermediate states 
of decomposition of the organic matter, due, very likely, to the mi- 
crobes and living germs of disease, which are nearly always present 
with decomposing organic matter. Nitrous acid, which combines 
with alkalies and alkaline earths to produce nitrites, is an interme- 
diate state between ammonia and nitric acid salts or nitrates. 
The metallic poisons apt to be found in potable waters are lead, 
zinc, iron, and copper. Chromium and arsenic are rarely found, and 
their presence in water, in any quantity, should be considered dan- 
gerous. 
Authorities differ as to the amounts of metal which would be 
considered injurious. Wanklyn states that “ a good drinking-water 
should not contain more than one-tenth or two-tenths grains of iron 
per gallon, or more than one-tenth of lead or copper.” It is a ques- 
tion whether so small a quantity of iron should condemn a water. 
Many iron-springs, considered healthful, contain a much larger 
amount. Undoubtedly, the form in which the iron-salt exists would 
largely influence its action. 
Well-authenticated cases of lead-poisoning have been occasioned 
by the cumulative action of lead which had been taken into the 
system in water containing 0.2 parts of lead per 100,000. 
A very simple test for metals can be made by taking a miniature 
gallon of the water (70 cubic centimeters) in a clean porcelain dish, 
adding three drops of sulphide of ammonia, which should give but 
a very slight coloration to the fluid, and which should be instantly 
cleared up and become invisible by the addition of a few drops of 
hydrochloric acid. Good water will answer to this test, and water that 
does not should be examined carefully and quantitatively for the 
presence of metallic impurities, before being accepted as potable. 
Microscopic Examination of Water.—There are many living or- 
ganisms, both animal and vegetable, which infest some waters, and 
which have to be examined microscopically. The microbes, ferments, 
and germs existing in some waters are the causes of many diseases 
flesh is heir to. Every year scientific research, especially with the aid THE IMPURITIES OF WATER. 
9 
of the microscope, is bringing to light new facts as to the presence 
and influence on human life and health of these minute organisms. 
The microscopic examination of water is not so much to deter- 
mine the larger forms of animal and vegetable life, as it is to separate 
and identify the septic or pathogenic microbes that are due to sewage- 
contamination, or are taken up from the air and soil in fever- and 
cholera-in fee ted districts. Decomposing nitrogenous organic matter 
we cannot say positively is poisonous, but we know by the aid of the 
microscope that associated with it are many microbes, some of which 
may be germs of specific diseases. 
These microbes are the different forms of Bacillus, as the B. tuber- 
culosis, which is the organism causing tubercular consumption; the 
“ Comma Bacillus ” of Koch, which is now generally conceded to be 
the cause of Asiatic cholera, and others which have not been so posi- 
tively identified, such as the Bacilli of typhoid and relapsing fevers, 
and that of yellow fever, which Dr. Freire, of Brazil, claims to 
have identified and cultivated. These organisms are only found 
in waters polluted with surface drainage and sewage contaminated 
by the dejecta of fever patients, the sputum of persons suffering 
from tubercular consumption, or similar matter expelled from the 
bodies of patients in some of the many diseases caused by the pres- 
ence of pathogenic microbes. These dangers are now so universally 
recognized, that State Boards of Health are publishing very stringent 
rules for the destruction of such poisonous matter, and, indeed, of 
anything with which it may have come in contact. 
The investigation and the determination of the different forms of 
microbes require the highest skill of the trained microscopist; and 
any statements made by investigators without such training and skill 
are very likely to be erroneous. These organisms are among the 
smallest and least differentiated with which the microscopist has to 
deal. They are distinguished by different methods of cultivation, 
and by the way in which the different groups take certain well-known 
and distinctive stains; the water-soluble aniline dyes being those 
generally used for this purpose. 
Micro-organisms are classified as aerobic and anaerobic, (or those 
which require oxygen for their development and those which do not), 
septic and 11011-septic, pathogenic and non-pathogenic; the septic 
being those which cause putrefaction in dead bodies, while the patho- 
genic are those which cause disease. 
These minute organisms may be separated from water by adding 
about one cubic centimeter of a one and one-half per cent, solution 10 
THE IMPURITIES OF WATER. 
of osmicacid to 30 or 40 cubic centimeters of water. All organisms 
are by this reagent precipitated as a thick, dark-colored deposit, 
from which the water is decanted off, leaving the deposit to be ex- 
amined afterwards under the microscope. In this deposit will be 
found a large number of septic and non-septic organisms which occur 
in all surface waters; and without careful training in a biological 
laboratory, it will be impossible to distinguish the various forms. 
Cultivation-experiments are carried on, either by plate- or “ flask-” 
culture, in the different organic or inorganic media which have been 
proved suitable for the purpose. A list of such media can be found 
in any of the standard works on microscopy; most fully, perhaps, in 
Klein’s “Micro-Organisms and Disease,” fourth edition. The 
methods of sterilizing all the apparatus and media, and of preserving 
them from contamination by the air, or from any other cause, are 
there explained. 
After inoculating the culture-medium, the growth of the colonies 
is carefully watched for several days ; and if the colonies appear to 
be pure—that is, composed of only one microbe—fresh tubes or 
plates are inoculated, and this is repeated several times, until there 
is no doubt of the purity of the culture. 
The microbes must then be studied by their reaction with certain 
stains, and by their effect upon living animals. The number of or- 
ganisms in water is estimated by inoculating a certain amount of 
sterilized gelatine on a plate with a measured amount of water and 
counting the number of colonies which develope. 
The Total Solid Residue.—The total solid residue in water varies 
from 5 parts per 100,000 in some deep, pure spring-waters to 4100 
parts in ocean-water. The character of this residue, as well as its 
amount, should be known, to establish the value of water for drink- 
ing. In most cases, where the total solid residue left upon evapora- 
tion does not exceed 40 parts per 100,000, it is not found upon 
examination to injure the water for such purposes. A larger amount 
than 40 parts per 100,000 should occasion a further investigation of 
the water. Of course, if the total solid residue consists of very 
poisonous matter, a smaller amount will cause injury. 
The solid residue may consist of lime, soda, magnesia and potash, 
or organic matter, and of finely divided silica. The chloride, bi- 
carbonate, and sulphate are the salts of lime most commonly looked 
for in waters to be tested as to fitness for drinking and cooking. 
The presence of more than 15 parts per 100,000 of these lime salts 
should condemn a water for such purposes, under ordinary circum- THE IMPURITIES OF WATER. 
11 
stances. However, in a good many of the Western states, the peo- 
ple are obliged to use water containing a larger amount of lime than 
this. A large amount of lime in drinking-water is liable to produce 
goitre, calculus, urinary and dyspeptic diseases. On the other hand, 
the presence of lime salts in sufficient quantity to render the water 
perceptibly hard, yet less than 35 parts per 100,000, has not proved 
unwholesome. Jn fact, many cities having hard drinking-water 
have a very favorable mortality as compared with similar cities 
having soft drinking-water, carrying less than 15 parts per 100,000 
of lime salts. 
The following definition of liquids which should be deemed pol- 
luting and inadmissible into a stream, was formulated by the Rivers 
Pollution Commission of Great Britain (1886). 
(a.) Any liquid which has not been subjected to perfect quiet in 
subsidence-ponds of sufficient size for a period of at least six hours, 
or which, having been so subjected to subsidence, contains in sus- 
pension more than one part by weight of dry organic matter in 
100,000 parts by weight of the liquid, or which, not having been so 
subjected to subsidence, contains in suspension more than three parts 
by weight of dry mineral matter, or one part by weight of dry or- 
ganic matter in 100,000 parts by weight of the liquid. 
(b.) Any liquid containing, in solution, more than two parts by 
weight of organic carbon or 0.3 part by weight of organic nitrogen 
in 100,000 parts by weight. 
(c.) Any liquid which shall exhibit bv daylight a distinct color 
when a stratum of it one inch deep is placed in a white porcelain or 
earthenware vessel. 
(d.) Any liquid which contains in solution, in 100,000 parts, by 
weight, more than two parts by weight of any metal except calcium, 
magnesium, potassium, or sodium. 
(e.) Any liquid which in 100,000 parts by weight contains, 
whether in solution or suspension, in chemical combination or other- 
wise, more than 0.05 part by weight of metallic arsenic. 
(f.) Any liquid which, after acidification with sulphuric acid con- 
tains, in 100,000 parts by weight, more than one part by weight of 
free chlorine. 
(g.) Any liquid which contains, in 100,000 parts by weight, more 
than one part by weight of sulphur, in the condition of either sul- 
phuretted hydrogen or a soluble sulphuret. 
(h.) Any liquid possessing an acidity greater than that which is 12 
THE IMPURITIES OF WATER. 
produced by adding two parts by weight of real muriatic acid to 
1000 parts by weight of distilled water. 
(i.) Any liquid possessing an alkalinity greater than that which 
is produced by adding one part by weight of dry caustic soda to 1000 
parts by weight of distilled water. 
(k.) Any liquid exhibiting a film of petroleum or hydro-carbon 
upon its surface, or containing in suspension, in 100,000 parts, more 
than 0.05 part of such oil. 
To these standards was attached the proviso, that “ no effluent 
water shall be deemed polluting if it be not more contaminated with 
any of the above named polluting ingredients than the stream or 
river into which it is discharged.” 
Mineral Waters.—Natural spring-waters impregnated with min- 
eral substances to such an extent as to have a medicinal effect, are 
called mineral waters Such waters are commonly divided, accord- 
ing to the character of the foreign substances held in solution, under 
the heads of carbonated, alkaline, sulphuretted, saline (including 
magnesian, chalybeate, and chlorinated), and siliceous waters. Tt is 
not necessary to describe these various classes here. The subject is 
one, with the general features of which our members are presumed 
to be acquainted, and the thorough discussion of which, though it 
would be both pertinent and valuable, is not within the purpose of 
the present paper. 
Commercial Analyses.—By far the most common commercial 
analysis of water is made to determine its fitness for making steam. 
Water containing more than 5 parts per 100,000 of free sulphuric 
or nitric acid is liable to cause serious corrosion, not only of the 
metal of the boiler itself, but of the pipes, cylinders, pistons and 
valves with which the steam comes in contact. Sulphuric acid is 
the only one of these acids liable to be present in the water from 
natural sources; it being often produced in the waters of the coal 
and iron districts, by the oxidation of iron pyrites to sulphate of 
iron, which, being soluble, is lixiviated from the earth strata and 
carried into the stream. The presence of organic matter taken up 
by the water in its after-course, reducing the iron and lining the 
bottom of the stream with red oxide of iron, and leaving a consider- 
able proportion of the sulphuric acid free in the water. This is a 
troublesome feature with the water necessarily used in many of the 
iron districts of this country. The sulphuric acid may come from 
other natural chemical reactions than the one des3ribed above. THE IMPURITIES OF WATER. 
13 
Muriatic and nitric acids, as well as often sulphuric acid, may be 
conveyed into water through the refuse of various kinds of manu- 
facturing establishments discharged into it. 
The large total residue in water used for making steam causes the 
interior linings of the boilers to become coated, clogs their action and 
often produces a dangerous hard scale, which prevents the cooling 
action of the water from protecting the metal against burning. 
Lime and magnesia bicarbonates in water lose their excess of car- 
bonic acid on boiling, and often, especially when the water contains 
sulphuric acid, produce, with the other solid residues constantly be- 
ing formed by the evaporation, a very hard and insoluble scale. A 
larger amount than 100 parts per 100,000 of total solid residue will 
ordinarily cause troublesome scale, and should condemn the water 
for use in steam-boilers, unless a better supply cannot be obtained. 
The following is a tabulated form of the causes of trouble with 
water for steam-purposes, and the proposed remedies, given by Prof. 
L. M. Norton, in his lecture on “ Industrial Chemistry 
Brief Statement of Causes of Incrustation. 
1. Deposition of suspended matter. 
2. Deposition of dissolved salts from concentration. 
3. Deposition of carbonates of lime and magnesia by boiling off 
carbonic acid, which holds them in solution. 
4. Deposition of sulphates of lime, because sulphate of lime is but 
slightly soluble in cold water, less soluble in hot water, insoluble 
above 140 degrees centigrade. 
5. Deposition of magnesia, because magnesium salts decompose at 
high temperature. 
6. Deposition of lime soap, iron soap, etc., formed by saponifica- 
tion of grease. 
Various Means for Preventing Incrustation. 
1. Filtration. 
2. Blowing off. 
3. Use of internal collecting apparatus or devices for directing the 
circulation. 
4. Heating feed-water. 14 
THE IMPURITIES OP WATER. 
5. Chemical or other treatment of water in boiler. 
6. Introduction of zinc into boiler. 
7. Chemical treatment of water outside of boiler. 
Tabular View. 
Troublesome Substance. 
Sediment, mud, clay, etc. 
Readily soluble salts. 
Bicarbonates of lime, magnesia, 
iron. 
Sulphate of lime. 
Chloride and sulphate of magne- 
sium. 
Carbonate of soda in large 
amounts. 
Acid (in mine waters). 
Dissolved carbonic acid and oxy- 
gen. 
Grease (from condensed water). 
Organic matter (sewage). 
Organic matter. 
Trouble. 
Incrustation. 
U 
U 
a 
Corrosion. 
Priming. 
Corrosion. 
u 
(( 
Priming. 
Corrosion. 
Remedy or Palliation. 
Filtration. 
Blowing off’. 
Blowing off. 
Heating feed. Addition of caus- 
tic soda, lime, or magnesia, etc. 
Addition of carbonate of soda, 
barium chloride, etc. 
Addition of carbonate of soda, etc. 
Addition of barium chloride, etc. 
Alkali. 
Heating feed. Addition of caus- 
tic soda, slacked lime, etc. 
Slacked lime and filtering. Car- 
bonate of soda. 
Substitute mineral oil. 
Precipitate with alum or ferric 
chloride and filter. 
Ditto. 
The mineral matters causing the most troublesome boiler-scales 
are bicarbonates and sulphates of lime and magnesia, oxides of iron 
and alumina, and silica. The analyses of some of the most common 
and troublesome boiler-scales are given in the following table: I'UE IMPURITIES OF WATER. 
15 
Analyses of Boiler-Scale. 
c 
’s 
Sulphate 
Lime. 
Magnesia. 
Silica. 
Peroxide 
Iron. 
Water. 
Chloride 
Soda. 
Carbonate 
of Lime. 
Lime, Cat 
Sulphuric 
Acid. 
Carbonic 
Acid. 
Authority. 
From 
British 
Admiralty 
Report. 
Steamer 
Amethyst 
94.04 
2.88 
trace 
trace 
2.45 
trace 
Admir’lty 
Report. 
Malabar 
95.93 
3.10 
0.40 
0.40 
Fox 
77.30 
10.55 
trace 
5.80 
6.00 
Patrothns 
96.37 
1.62 
0.60 
0.60 
1.-5 
“ 
“ 
Velindra 
Other Sea- 
Going Scale. 
91.38 
2 31 
1.40 
1.60 
3.30 
(Wallace.) 
Atmospheric 
Pressure of 
0.34 
33.95 
40.05 
trace 
1.33 
24.67 
trace 
Wallace. 
0.4 to 0.51 
66.88 
18.96 
“ 
0.50 
11.66 
“ 
0 
“ 
0.7 
♦>9.77 
15.75 
0.16 
1.36 
8.25 
0.99 
3.44 
“ 
1 to 1.12 
74.21 
14.95 
0 57 
1 34 
6.89 
2.04 
“ 
1.4 
72.85 
13.18 
0.80 
2.40 
8.27 
2.16 
0.34 
“ 
Hartford, 
Conn., River 
Water 
22.70 
5.32 
4.57 
40.0 
2.63 
15.62 
Mac Farlane. 
Same as above 
after using 
Soda Ash.... 
18.55 
3.33 
2.23 
42.35 
24.95 
« 
Holyoke, 
Mass 
Southington, 
12.49 
7.34 
3.57 
29.41 
0.64 
25.03 
“ 
Conn., Well 
Water I. ... 
23.50 
10.66 
0.60 
34.83 
6.89 
18.74 
« 
11 
Danbury, 
Conn., Brook 
28.85 
5.58 
1.01 
40.90 
2.33 
17.03 
15.07 
4.94 
12.77 
34.66 
0.48 
21.15 
(1 
North Adams, 
Mass., Brook 
St. Croix 
4.23 
4.27 
1.12 
35.01 
46.51 
“ 
0.61 
4.80 
1.12 
3S.49 
52.03 
Atmospheric 
Pressure. 
2 5 to 3 
50.75 
1.19 
0.47 
2 24 
3.68 
44.25 
Fischer. 
3 
67.14 
9.69 
trace 
5.28 
7.90 
14 65 
“ 
3.5 
79.71 
3.83 
0.88 
1.67 
3.45 
8.30 
“ 
3.5 
31.96 
7.11 
trace 
2.10 
2.31 
55.65 
“ 
5 
80.74 
4.36 
0.52 
4.21 
8.20 
“ 
5—6 
98.04 
0.20 
N. Y.C.& H. 
Ry.,No. 1... 
A “ 2... 
74.07 
9.19 
0.65 
0.08 
1.14 
14.78 
Chandler. 
71.37 
1.76 
“ 
“ “ 3... 
62.86 
18.95 
2.60 
0.92 
1.28 
12.62 
“ 
" “ 4... 
53.05 
4.79 
" 
“ “ 5... 
46.83 
5.32 
“ 
“ “ 6... 
30.80 
31.17 
7.75 
1.08 
2.44 
26.93 
" 
“ “ 7... 
4.95 
2.61 
2.07 
1.03 
0.63 
86.25 
“ “ 8... 
0.88 
2.84 
0.65 
0.36 
0.15 
93.19 
“ 
“ “ 9... 
4>1 
2.92 
“ 
“ “ 10... 
30.07 
8.24 
U 16 
THE IMPURITIES OF WATER. 
The following table shows the analyses of samples of water giving 
bad results for steam-purposes: 
Analyses in Parts per Hundred Thousand of Waters Giving Bad 
Results for Steam-Purposes. 
Bicarbonate of Lime 
Deposited on Boiling. 
Bicarbonate of Mag- 
nesia Depos’d on Boil’g 
Total Lime. 
Total Magnesia. 
Sulphuric Acid. 
Chlorine. 
Iron. 
Organic Matter. 
Alumina. 
Chloride of Sodium. 
Feed-water 
giving 
Scales 2.5—3... 
“ 3 atmosph. 
“ 3.5 “ 
“ 3.5 “ 
“ 5 
“ 5—6 “ 
Coal-mine wat’r 
Salt-well 
225 
88 
tr’ce 
63 
46 
tr’ce 
110 
151 
75 
130 
80 
32 
30 
19 
3 
0 
39 
0 
0 
25 
38 
89 
21 
70 
82 
50 
450 
147 
46 
155 
244 
599 
119 
1.90 
95 
161 
94 
61 
41 
85 
22 
9 
68 
32 
81 
39 
48 
120 
33 
81 
1.04 
68 
219 
121 
40 
89 
232 
306 
890 
360 
310 
210 
219 
28 
890 
293 
59 
91 
9 
770 
590 
990 
21 
38 
210 
1.90 
42 
1 
1 
\ Se 
i 
780 
38 
75 
70 
90 
38 
23 
e Ta 
Boil 
30 
21 
10 
hie 
erSc 
640 
30 
80 
D of 
ales. 
13.10 
36 
Fischer. 
A. E. Hunt. 
A. E. Hunt. 
Spring 
Monongahela 
Kiver* 
“ 
Allegheny riv’r 
near Oil-w’rks 
Many substances have been added with the idea of causing chem- 
ical action which will prevent boiler-scale. As a general rule, these 
do more harm than good; for a boiler is among the worst possible 
places in which to carry on a chemical reaction, where it nearly 
always causes more or less corrosion of the metal, and is liable to 
cause dangerous explosions. 
In cases where water containing large amounts of total solid resi- 
due is necessarily used, a heavy petroleum oil, free from tar or wax, 
which is not acted upon by acids or alkalies, not having sufficient 
wax in it to cause saponification, and which has a vaporizing-point 
at nearly 600 degrees Fahrenheit, will give the best results in pre- 
venting boiler-scale. Its action is to form a thin greasy film over 
the boiler-linings, protecting them largely from the action of acids 
in the water, and greasing the sediment which is formed, thus pre- 
venting the formation of scale and keeping the solid residue from 
the evaporation of the water in such a plastic, suspended condition 
* Taken near discharge-pipes from large manufacturing establishments. THE IMPURITIES OF WATER. 
17 
that it can be easily ejected from the boiler by the process of “ blow- 
ing off'.” If the water is not blown off* sufficiently often, this sedi- 
ment forms into a kind of a “ putty ” that will necessitate cleaning 
the boilers. Any boiler using bad water should be blown off every 
twelve hours. The formation of scale of hard residue on the boiler- 
linings will be almost entirely prevented by the use of this oil, which 
is manufactured in Pittsburgh, and sold in the markets under the 
name of “ Boiler Scale Resolvent.” 
Hardness of Water.—The hardness of water, or its opposite 
quality, indicated by the ease with which it will form a lather with 
soap, depends almost altogether upon the presence of compounds 
of lime and magnesia. Almost all soaps consist, chemically, of 
oleate, stearate, and palmitate, of an alkaline base, usually soda and 
potash. 1 he more lime and magnesia in a sample of water, the 
more soap a given volume of the water will decompose, so as to give 
insoluble oleate, palmitate, and stearate of lime and magnesia, and 
consequently the more soap must he added to a gallon of water in 
order that the necessary quantity of soap may remain in solution to 
form the lather, 'idle relative hardness of samples of water is still 
generally expressed in terms of the number of standard soap-meas- 
ures consumed by a gallon of water in yielding a permanent lather, 
rather than in parts per hundred thousand, for the reason that as the 
relative hardness of samples of water has come to be a commercial 
quality, and is determined by many who are not chemists, it has 
been found more difficult to change the method of reporting. As 
before explained, reports in degrees or grains per imperial gallon can 
be readily transposed in parts per hundred thousand by multiplying 
the number of grains by 10 and dividing the product by 7. 
'1 he standard soap-measure is the quantity required to precipitate 
one grain of carbonate of lime. 
It is commonly reckoned that one gallon of pure distilled water 
takes one soap-measure to produce a lather. Therefore, one is de- 
ducted from the total number of soap-measures found to be necessary 
to use to produce a lather in a gallon of water, in reporting the num- 
ber of soap-measures, or “ degrees ” of hardness of the water sample. 
In actually making tests for hardness, the “ miniature gallon,” or 
seventy cubic centimeters, spoken of on a previous page, is used 
rather than the inconvenient larger amount. The standard measure 
is made by completely dissolving ten grammes of pure castile soap 
(containing 60 per cent, olive oil) in a liter of weak alcohol (of about 
do per cent, alcohol). This yields a solution containing exactly 18 
TIIE IMPURITIES OF WATER. 
the evaporation of the water in such a plastic suspended condition 
sufficient soap in one cubic centimeter of the solution to precipitate 
one milligramme of carbonate of lime, or, in other words, the standard 
soap-solution is reduced to terms of the “ miniature gallon ” of water 
taken. The correctness of the standard soap-solution is standardized 
against a solution of one gramme of carbonate of lime, dissolved in 
hydrochloric acid, carefully neutralized with ammonia and diluted 
to one litre, so that each cubic centimeter represents one milligramme 
of carbonate of lime. 
If a water charged with bicarbonate of lime, magnesia, or iron, is 
boiled, it will, on the excess of the carbonic acid being expelled, de- 
posit a considerable quantity of the lime, magnesia, or iron, and 
consequently the water will be softer. The hardness of the water 
after this deposit of lime, after long boiling, is called the permanent 
hardness, and the difference between it and the total hardness is 
called temporary hardness. 
Lime salts in water react immediately on soap-solutions, precipi- 
tating the oleate, palmitate, or stearate of lime at once. Magnesia 
salts, on the contrary, require some considerable time for reaction. 
They are, however, more powerful hardeners; one equivalent of 
magnesia salts consuming as much soap as one and one-half equiva- 
lents of lime. 
The presence of soda and potash salts softens rather than hardens 
water. 
The applicability of a given water for very many of the manu- 
facturing industries requires its analysis for the contained impurities. 
The most common injurious impurities for manufacturing purposes 
are the free acids, excessive amounts of total solids, and salts 
affecting the relative hardness. 
Note by the Secretary.—Comments or criticisms upon the 
foregoing paper, whether private corrections of typographical or 
other errors, or communications for publication as “Discussion,” or 
independent papers, on the same or a related subject, are earnestly 
invited.