LECTURE ON WATER DELIVERED BEFORE | he t mcricati Instittite of the (jito of j| etc jjorh IN THE Academy of Music, January 20th, 1871. By C. F. CHANDLER, PH. D., trr» Professor of Analytical and Applied Chemistry, School of Mines, Columbia College; Professor of Chemistry in the New York College of Pharmacy; and Chemist to the Health Department of the City of New York. [Extract from the Transactions of the American Institute for 1870-71.] ALBANY: THE ARGUS COMPANY, PRINTERS. 1871. SCIENTIFIC LECTURE. WATER. Professor of Analytical and Applied Chemistry in the School of Mines of Columbia College. Charles F. Chandler, Ph. D., DELIVERED BEFORE THE AMERICAN INSTITUTE, AT THE ACADEMY OF MUSIC, JANUARY 20tu, 1871. Composition of Water. Water is the sole product of the combustion of hydrogen in oxygen or the atmosphere. The Hindoos and the Egyptians considered water the element from which all other bodies were formed. Among tHe Greeks the idea was maintained, that water was the first or fontal element; that from it all other bodies were formed; that even plants and animals owed their origin to it. Aristotle regarded water as one of four elements, and this idea was maintained for more than a thousand years, though the old idea that water was the primal ele- ment, seems to have been mingled with this idea, for it was supposed that those four elements, lire, earth, air and water were mutually con- vertible. Heat converted water into invisible air ; repeated evapora- tion, they said, converted water into earth, so that there seems to have been an original idea, that water was the only sole element. Lavoisier, in 1770, tested experimentally the question of the con- version of water into earth. It had long been known that when water was placed in a glass retort or alembic, and distilled, there remained behind a small quantity of earthy matter, and if the water was returned to the alembic and distilled again, the quantity of earthy matter increased, and it continued to increase as often as the water was distilled from it. It was supposed, therefore, that the water was gradually converted into earth. Lavoisier distilled three pounds of water again and again, in an alembic provided with a con- denser, the whole apparatus being hermetically sealed, that not a par- ticle of water should be lost. At the close of the experiment, ho 2 found that while the quantity of water had not diminished in the least, he had a residue of twenty grains of earthy matter in the alembic. As the water had not diminished, he justly concluded that it had not come from the water; it must then have been derived from the alembic itself. On cleansing the alembic and condenser, and weighing them, it was found that they had lost seventeen grains. Seventeen grains of the earthy matter had, therefore, been produced by the action of the boiling water on the glass. The remaining four grains were attributed by Lavoisier to the natural impurities of the water. Scheele, the great Swedish chemist, tested the same question, and not only proved that the earthy matter was derived from the glass, but analyzed it and found it to consist of the same constituents, potash, lime, and silica. Dalberg repeated the experiment in a silver vessel and obtained no earthy matter. So the conversion of water into earth was proved to be a fallacy due to the action of the water upon the glass vessel. Until ITBI, water was considered an element. Hydrogen had been known in the fifteenth century; had been prepared by the action of dilute sulphuric acid upon metallic iron, and was supposed to I>e phlogiston. Oxygen was discovered in 1774 by Scheele and Priestley; but it was not till 1781 that Cavendish proved water to be composed of oxygen and hydrogen; proved it to be a compound, instead of an element. He identified its constituents as the hydrogen long known and the oxygen which had been discovered a few years previous. The efforts of several of the most distinguished chemists were at once directed to the question of determining the proportions in which these elements were combined. Lavoisier investigated this subject, and made repeated analyses, but failed to arrive at the true propor- tions. Humboldt and Gay Lussac investigated the question, and decided that water contained eight parts by weight of oxygen, and one part by weight of hydrogen. In 1772, nitrogen was discovered in the atmosphere; and in 1775, Lavoisier proved that the air was a, mixture of oxygen and nitrogen. So it is just 100 years since the great fundamental discoveries were made upon which chemistry rests, and all the sciences, geology, mineralogy, physiology, etc., which are based upon it. The discovery of the composition of the atmosphere and of water may be truly said to be the great fundamental dis- coveries upon which the whole system is based. They constitute the starting point in our system ; and Lavoisier’s experiment stands out in bold relief as one of the first experiments upon record in which 3 the chemical balance was introduced; in which quantities were examined as well as qualities. The experiments of the alchemists, by which a large fund of fact had been accumulated, were all directed to the qualities of the products; but Lavoisier, when he introduced the balance, made the first great step in advance, and in this way decided the fate of the old phlogiston theory, and the many other theories which were based upon error. The composition of water is beautifully shown by the decomposing action of the voltaic current. I have here a voltaic battery, the wires from which terminate in plates of platinum. In this glass jar is water, which has been colored pink to make it visible, and has been acidulated to make it a good conductor of electricity. The voltaic current decomposes the water, and the constituent gases are set free at the surfaces of the platinum plates, from which they ascend in bubbles and displace the water in the two vertical tubes. Notice that the hydrogen from the negative pole occupies -twice the volume of the oxygen from the positive pole, but the oxygen being sixteen times heavier than hydrogen, this small quantity of oxygen weighs eight times as much as double the volume of hydrogen. I can show you the properties of these two gases by a simple experi- ment. Hydrogen is combustible. We have merely to cause it to escape by depressing this cylinder which contains it in a vessel of water, and apply a flame to indicate this fact. Now,you see that the hydrogen is burning with a pale bluish flame. Thus we have a com- bustible gas produced by the decomposition of water. Oxygen is not combustible, but it is a supporter of combustion. We will now transfer our cylinder, which contains the gas liberated from the positive pole of the battery, to a vessel of water, and depress it, to cause the gas to escape from the cock which I will now open. You see the spark on my taper has been kindled into flame by the gas, and that as often as I extinguish the flame and bring the spark into the gas, it lights again. \ on have now seen that the voltaic current decomposes water, set- ting free its component gases ; the combustible hydrogen, and the sup- porter of combustion, oxygen. Oxygen. Oxygen is the most abundant element in nature. Almost every other element on the earth’s crust occurs combined with oxygen, and really the earth’s crust is composed of the ashes produced by the com- bustion of the other elements. Still there is an excess of oxygen which we find in our atmosphere. You see the changed character 4 of the flame of the taper when introduced into this gas. Now I propose to burn a little phosphorus in one of these jars and some magnesium in another, simply to illustrate the character of oxygen in supporting combustion. In the atmosphere we have four volumes of nitrogen to every volume of oxygen, and the conse- quence is, that the combustion is retarded by this inert nitrogen. The nitrogen takes no part apparently in the chemical changes pro- duced by the atmosphere. The rapidity of the combustion depends greatly upon the rapidity with which the oxygen comes in contact with the combustible body. By removing the nitrogen, or rather by preparing an atmosphere free from nitrogen we simply hasten the combustion. We will now introduce the burning phosphorus into the jar of oxygen. You see how wonderfully the combustion is intensifled by the pure oxygen. The globe is now apparently filled with lire which it pains the eyes to behold. The white cloud which now fills the globe is phosphoric acid in the form of solid white par- ticles, which will ultimately settle to the bottom, forming a layer like snow. This is the ashes of the phosphorus. When your eyes have recovered somewhat from the effect of the dazzling light upon them, I will set fire to this piece of magnesium and introduce it into a globe of oxygen. Now watch the burning metal, the light is whiter and more bri 11 iant even than that produced by the phosphorus. This is the metal which exists in Epsom salt, and the white product or ash is magnesia. The affinity of oxygen for phosphorus is so great that we may cause them to unite under water. In this conical glass we have a piece of phosphorus; on pouring this hot water upon it, it is melted, and now, on introducing a jet of oxygen you see we have the phos- phorus actually burning under water; the phosphoric acid is dis- solved by the water as fast as it is formed, so it is not visible as it was when we burned the phosphorus in dry oxygen gas. Many sub- stances have the power to decompose water by robbing it of its oxy- gen, setting the hydrogen free. This metal potassium which I now project upon the surfarce of the water in the jar, rapidly appropriates the oxygen of the water forming potassa which dissolves, the hydro- gen escapes and you see the heat of the reaction has set it on fire and it bums with a beautiful violet flame. The color of the flame is due to a portion of the potassium which has vaporized. The water is thus actually set on fire by the potassium. By placing a bit of this metal on the priming of a cannon, and applying an icicle we fire the piece, I will spare you the shock of the explosion, by omitting the experiment, But the principle will be as 5 well shown when I apply this icicle to the wick of my spirit lamp, on which I have placed a bit of potassium. For, see, it lights at once. We have, therefore, set an icicle on tire, and thus lighted the lamp. Hydrogen. In this jar we have the other constituent of water, hydrogen. As I hold the jar with its opening downward it will not readily escape, as it is the lightest substance known, being only one-fonrteenth as heavy as air. Now, on bringing the burning taper near the mouth of the jar, you see the hydrogen burns where it is in contact with the air, while the taper is extinguished. As I withdraw the taper, it is relighted on passing through the flame of hydrogen. This experiment illustrates the combustibility of the hydrogen, and its inability to support the combustion of the taper. The terms combus- tible and supporter of combustion are merely relative; in an atmos- phere of hydrogen the oxygen would bo combustible and the hydrogen the supporter, while the taper would be incombustible. I have here a little apparatus containing zinc and dilute sulphuric acid, from which hydrogen is being evolved. I propose simply to burn a little of the hydrogen beneath this globe to form water by the combustion. In a few moments you will see the jar covered with moisture, which is water produced by the combustion. In fact, a spirit lamp will produce water in exactly the same manner, every sub- stance that contains hydrogen produces water when It is burned in the atmosphere. You see, the jar has become dimmed and damp with the moisture, which is the result of this combustion of the hydrogen. Properties oe Water. Water is the most important and the most remarkable of all our chemical compounds. It covers three-quarters of the earth’s surface, in the form of ocean, lake and river, and in the higher latitudes snow, ice, glacier and iceberg. Rising in the form of vapor it produces by condensation clouds, fog, mist, rain and snow. In the vege- table kingdom it is ever present, varying in quantity from ninety-nine per cent down to fifteen or twenty. Dry wood contains twenty per cent of moisture. Animals consist largely of water. An average man, weighing 150 pounds, contains about 11G pounds of water. The rocks contain it; some hold it in large quantity. Gypsum contains twenty per cent of water, and even rocks, which are not hydrated compounds, contain it in moderate quantity, a fraction of a per cent. It is a bad conductor of heat, but has a great capacity for heat. A cubic mile of 6 water in cooling one degree warms over 3,000 cubic miles of air a like amount. And when water freezes it evolves a large amount of beat. A cubic yard of ice, in the process of melting, absorbs the beat which it gives out in freezing; it takes up enough heat to change the tem- perature of 21,000 cubic yards of air from 52° to 32° Fahrenheit. On account of this great capacity for heat, this absorption of beat when ice melts and this evolution of heat when it freezes, water becomes the great regulator of the temperature of the earth. Water combines with other substances, and at times plays the part of an acid with strong bases. When water is thrown upon quick- lime we have produced the hydrate of lime, and the water plays the part of an acid, while in oil of vitriol we have water playing the part of a base. A second degree of affinity of water for other substances is illus- trated when substances crystallize from aqueous solutions. They lock up a certain quantity of water which we call water of crystalli- zation. Such is the case with alum, borax, and carbonate of soda. A still weaker affinity is manifested in the process of solution. All substances are soluble in water to a greater or less degree. Solids and gases are taken up by it. Some of our ordinary reagents are simply solutions of gas in water, as ammonia, hydrochloric acid, and hydrosulplmric acid. Besides these three forms of combination, where water plays the part of an acid or a base, is secreted in crystals or acts as a solvent, we have other and weaker forms of combination. All solid substances contain more or less water. Rocks, when exposed to a temperature of 212°, lose in weight on account of the escape of the moisture which they contained. This is called hydro- scopic moisture. Natural Waters. Water being a great solvent, dissolves to some extent, whatever it comes in contact with. Even atmospheric waters, the rain and melted snow are not pure. Rain, as it falls through the air, washes out the solid particles of dust, and the germs of animals and plants. And in addition to these it dissolves the oxygen, the nitrogen, and carbonic acid of the atmosphere, the oxygen to a greater extent than nitrogen. Air which is dissolved in water is much richer in oxygen than ordi- nary atmospheric air. This seems to be a special provision of nature for the fishes. They extract the small quantity of oxygen which is dissolved by the water from the air. The quantity is small. Twenty- five cubic feet of water take up only a cubic foot of oxygen. But 7 tins quantity is sufficient for the maintenance of life in the fishes; their gills enable them to absorb it, and they die without it. Water which is collected from roofs in the city is never pure. It contains gases which are only develped in cities, sulphur compounds, products of the combustion of coal, and animal matter. After thunder storms, the rain water is always found to contain minute quantities of nitric acid produced by the electric sparks which cause the oxygen and nitrogen to unite. Spuing Waters, Terrestrial waters are always impure. Rain falling upon the earth’s surface is absorbed by the porous soil, and the material of which the soil is composed, being to a greater or less extent soluble, the water becomes contaminated with mineral matter. The charac- ter of spring water, therefore, depends upon the character of the soil through which it has passed before it issues as a spring. In New England, where the rocks are granitic, and the minerals, chiefly quartz, feldspar and mica, water is extremely pure. But in lime- stone countries where carbonate of lime and magnesia abound, we find the spring waters largely contaminated with these substances. These carbonates are rendered much more soluble in water by the carbonic acid present, which forms bicarbonates with them. In this jar is some lime-water; a clear solution of lime. The car- bonic acid water, which I now add from the syphon bottle, produces carbonate of lime, which makes the liquid milky; but yon see it now disappears on the further addition of carbonic acid. The clear liquid now contains the bicarbonate of lime. To such solutions of bicarbon- ate of lime are due many curious phenomena in nature. Where they trickle down from the roofs of caves, the evaporation of a portion of the carbonic acid causes the separation of an equivalent quantity of carbonate of lime. Each drop, as it hangs for a moment and then falls, leaves behind a thin pelicle of solid spar, and finally, in years of dripping, a stalactite is formed. Where the drops strike the floor of the cave, corresponding stalagmites gradually spring up, often meet- ing the stalactites at last, and forming columns of glistening stone. Sometimes where the water falls from a crevice, a series or row of col- umns is produced, which finally becomes a solid wall or partition of spar. On boiling solutions of bicarbonate of lime and magnesia, the excess of carbonic acid is expelled, and the carbonates having no longer a solvent are precipitated. In this way incrustations are formed in tea- kettles and steam boilers. 8 Spring water is generally very clear, although it may be quite impure. It holds its impurities in solution. The soil through which it has passed, although it has conferred upon it its impurities, has at the same time filtered it, and thus rendered it clear and sparkling. As it comes from below the surface, it is generally cool. For these rea- sons spring water has always been highly prized. Wells which are dug down below the surface, are supplied partly by springs and partly by local drainage. The water may be very pure, or, if the surrounding soil is calcareous or charged with the refuse animal matter of neighbor- ing dwellings, it will be very seriously contaminated with impurities. Artesian Wells. Occasionally wells are sunk to great depths by boring. Such wells are called artesian wells, from the district in France where they were first bored. The earth’s crust consists in many localities of strata of gravel, sand or clay, resting upon sandstones, limestones or shales. In many cases these strata are in basins, and their edges often come to the surface at the margin of the basins. Some of these strata, which are porous, constitute reservoirs of water, and by boring down to them this water is reached. It may rise above the surface and overflow if the strata rise elsewhere to higher levels ; otherwise it must be pumped. Often the pressure of gases forces the water above the surface. At Grenelle, near Paris, an artesian well was bored down 1,600 feet, or nearly one- third of a mile. The water rose eighty feet above the surface, and tiowed'at the rate of ninety cubic feet per minute. Coming from so great a depth, it is very warm, and must be stored in a reservoir to cool. At Rochefort, in France, is a well 2,670 feet deep, or more than half a mile. This is the deepest well in Europe. Some of the deepest artesian wells have been put down in this country. At Louisville, Ky., there is one 2,086 feet deep, the water of which has a temperature of 82° Fahrenheit. But instead of being suitable for domestic purposes, the water proved to be heavily charged with chemical compounds, which give it a medicinal value. At Charleston, S. 0., there is a well 1,250 feet deep, yielding similar mineral water. At Columbus, Ohio, an artesian well, at the depth of 180 feet, yielded sulphur water; but it proved to be hard water. At the depth of 675 feet salt water was obtained. As fresh water was required, the well was pushed down a half a mile, or 2,575 feet; but no water was obtained of satisfactory quality. At St. Louis a well was bored to the depth of 3,881 feet, or two-thirds of a mile; but no water of any consequence was obtained, and the well is a failure. 9 In many instances water which rises in artesian wells comes from great distances. At Tours, in France, the well is sometimes obstructed, and when the obstruction is removed, it is found that the leaves which come to the surface, and which caused the obstruction, do not grow within a hundred miles of Tours; showing that there is some sub- terranean communication by which the water, as well as the leaves, is brought from a distance. Ordinary spring waters (fresh waters, as they are generally called) contain salts of the alkalies and alkaline earths: Chlorides, sulphates, and bicarbonates of potassa, soda, lime and magnesia. The most com- mon salts are the chlorides of potassium and sodium, the sulphates of soda and lime, and the bicarbonates of lime and magnesia. Nature of the Impurities of Spring Water. Besides these alkaline and earthy salts, we almost invariably find silica, the substance of quartz, to the amount of a grain or less in a gallon. In wells which receive drainage waters, in the neighborhood of dwellings, we generally find nitrates, nitrites and ammonia salts, derived from decomposing animal matters in the soil. I have here a sample of impure well water, in which you shall see some of the more common impurities. Carbonic acid is shown in this jar by the addition of lime-water, which forms carbonate of lime, visi- ble to you now as a milky precipitate. Lime is apparent to you as a white precipitate, produced by the oxalate of ammonia, which 1 am now adding to the second jar of the water. Sulphates are shown by the white precipitate which will appear on the addition of hydrochloric acid and chloride of barium to this third jar. You see it forming now. Chlorides, common salt, etc., are now apparent in this jar, to which I have just added nitric acid and nitrate of silver. There is a popular idea, originated by some itinerant temperance lecturer who pretended to analyze liquors, that chemical analyses are made with the aid of a machine, into which the liquid to be analyzed is poured, and from which on turning a crank the constituents flow successively. The lecturer referred to, employed such a machine in analyzing wines and liquors to terrify his audience, showing the log- wood, fusil oil, strychnine, etc., which he supposed to be used in com- pounding them. You see, however, that reagents are employed to detect and separate the different constituents of the water. No machine will answer the purpose. Magnesia cannot be detected in the presence of lime; but I have here a sample of this water, from which the lime has been removed, and now on the addition of phos- phate of soda you see the white precipitate of magnesia. 10 Yon Lave now seen me detect some of the common constituents of spring water. These reactions are produced by almost all spring waters; hut their intensity varies with the quantities of the impurities. Hard and Soft Waters. Lime salts in water are the cause of what is called hardness. They decompose the soap used in washing, forming a tlocculent insoluble compound, and destroying its detergent properties. In Glascow the saving to the people in soap, due to the introduction of the pure water of Loch Katrine, in place of the hard well waters previously used, is said to amount to $lBO,OOO per annum. Yon see before me two tall jars of water. One water is pure and soft; the other contains much lime and is hard. I will add to each a solution of soap in alcohol. You see now that on shaking this jar a tine froth or soap suds is produced. This is the soft water. Now I will shake the other jar, and yon see we get no suds; but the liquid becomes white and milky. The lime has destroyed the soap. Soap is, therefore, an excellent reagent for testing water; a fact which is well known, though few but chemists understand that it indicates the lime compounds only. As bicarbonate of lime is destroyed by boiling, with the formation of insoluble carbonate of lime, which does not act on soap, it is said to produce temporary hardness, while sulphate of lime, which is not affected by boiling, produces permanent hardness. Another impurity which is always present in water, but whose exact chemical character has not been fully determined, is organic matter. This is undoubtedly a collective term for a great many different sub- stances derived from decomposing vegetable and animal matters. I will show you a test which is often used for the detection of organic matter. It is the permanganate of potassa. You notice the beautiful pink color which is produced as I add a few drops of this reagent to this jar of water. But you see the color gradually fades away. This is because the organic matter takes oxygen from the permanganate, destroying it, and undergoing oxydation itself. The quantity of permanganate the water is capable of bleaching is a rough index of the proportion of organic matter present. A little time is required for the organic matter to bleach the permanganate; the sample of water before you received an addition of organic matter for the occasion, that you might not be obliged to wait long to see the color disappear. As the per- manganate destroys the organic matter it is often used to purify Organic Matter. 11 impure waters, organic matters being the most objectionable impurities which occur in natural waters. Pond, Lake and River Waters. Pond, lake and river waters are generally purer than spring water, (or the reason that while those bodies of water receive the waters of springs, they also receive a considerable quantity of water which has simply run over the surface of the earth. When a shower comes up, a portion of the water goes through the soil and issues as a spring; but a large portion of it runs over the soil, and goes into the lakes and rivers without taking with it much mineral matter. For this reason the waters of lakes and ponds are much purer than those of the springs in the same locality. One of the purest waters known is the water of the river Loka in Sweden, which contains only one-twentieth of a grain of impurities in a gallon. Rivers are more likely to be charged with suspended impurities, for the reason that their waters, which have not been tillered through the soil, carry with them a certain quan- tity of clay and organic matter. That is what we see in Potomac water; it lias had no opportunity to settle, and has not been filtered out. When water flows into lakes and the sediment subsides, it becomes clear. But in streams where the water runs rapidly, it has no opportunity to settle, and becomes very muddy. The water of the Mississippi contains forty grains of mud per gallon; and it is estimated that this river carries 400,000,000 tons of sediment per annum into the Gulf of Mexico. The Ganges is said to carry down 6,368,000,000 cubic feet annually. This transportation of mud in suspension has produced large deposits at the months of these rivers. All of the State of Louisiana, and considerable portions of other States which border upon the lower Mississippi, have been formed by the depo- sition of these sediments brought from higher levels. This mud is rich in plant food, and the land which it produces is very fertile. The Mohawk flats are famous for their fertility; and the annual over- flow of the Rile is the chief reliance of the poor Egyptians who culti- vate the fields enriched by its sediments. Living Organisms in Water. In addition to the soluble and suspended impurities already men- tioned, we find living organisms in water, animals and plants. I will call your attention to the diagram, on which you will see some of the most common forms of the Croton and Ridgewood waters. It was prepared by Dr, William B. Lewis for the Metropolitan Board of Health : 12 Catalogue of the animal and vegetable object* found, in the sediment of Croton water taken from, the Central Park and Fifth avenue reservoirs during October, November and, December, 1869: a. Asterionella formosa, vegetable, a diatom, x 812. b. Pediastrum simplex, vegetable, a desmid, x 200. c. Cyclotella astrsea, vegetable, a diatom, x 200. cl. Yorticella , an animalcule, x 312. e. Conferva, vegetable, “ green scum,” x 40. /. Epithelial cell, probably from manure during freshet, x 200.