Within the past few years another process has been successfully introduced, by which water, ordinarily unfit for drinking or beverage-manufacturing purposes, has been rendered sweet and wholesome. The system is styled aeration. By this is meant, not the impregnation of water with carbonic acid gas, as it is understood in England and elsewhere, where all mineral waters are erroneously known as "aerated waters," but submitting it, under favorable conditions, to atmospheric pressure, whereby the deficiency in oxygen is supplied, the absence of which leads to the rapid development of organisms fatal to its purity. Air, as is well known, consists of twenty-one parts by volume of oxygen and seventy-nine parts of nitrogen, but the oxygen is more soluble in water than the nitrogen. This new departure, it may safely be said, is of vast importance to manufacturers of carbonated beverages, and the latest information and more recent experiments will serve to acquaint them with a matter which is just at present receiving special study and investigation at the hands of leading scientists.

Oxygen, as the researches of Tyndal, Pasteur and other students of the germ theory and the effects of different gases on the purity of water and other fluids have established, exercises a powerful purifying effect on water, as indeed on any other fluid containing organic matter. Just as it encourages combustion and promotes life, so, when brought in contact with organic matter in water, it causes its natural destruction and decomposition, effecting its resolution into harmless elements, among which carbonic acid is one of the most prominent, and purifying the water of its presence. Tumbling cascades, rapid currents and rolling waves are all factors in the natural oxidization of water; and in nature no moving body of water becomes foul of itself, while even such impurities as may be communicated to it in the shape of land drainage, town sewerage, etc., are neutralized and rendered innocuous with the greatest facility. The surfaces of such waters are constantly changing, and each fresh surface is so disposed that it can readily absorb from the atmosphere the oxygen needed for its purification. Contrast this with a stagnant water, in which the upper strata alone can absorb a limited amount of oxygen, and with the rapidity with which it becomes foul, impregnated with organic matter, alive and dead, and with disease germs which it freely distributes throughout its vicinity. Science and experiment have even more definitely established the truth of these theories.

The oxygen has a destructive as well as a preserving effect upon organism and organic matter, according to the conditions under which the action takes place.

The amount of material on the face of our earth, available for nature to construct and sustain all organism of, is not infinite but strictly confined; and all of it is in constant use. A portion of the existing organism must die and decompose to furnish the material for the construction of newly rising organisms. It is the function of the atmospheric oxygen to do the destructive work and also to build up anew and preserve.

An article upon "Air-Treatment," in the American Chemist for August, 1871, in explanation of this living principle, opens as follows: "The problem, the solution of which is involved in the subject of Air-Treatment, has been fitly expressed by Professor A. W. "Williamson, F. E. S., in a lecture at London, last November, upon Fermentation, in the following words (Chem. News, Nov. 11, '70, page 235): 'If all the good has to come from the oxygen and all the worst evil come from the oxygen, it must be of the greatest importance to ascertain what are the conditions under which the beneficial action can be exercised, and what are those under which its detrimental influence occurs"

Fresh meats, fruits and vegetables, confined in close boxes or rooms, are quickly tainted and putrefy; the same articles exposed to brisk drafts of air keep for an indefinite length of time. The water of streams, especially of lively currents, is sweet; where some of it fills a stagnant pool, it is soon nauseous with putrefying elements; still it is rendered sweet again by frequent violent agitation with air. Wine men cause wine, slightly diseased, to pass in spray through the air to restore it. Fungoid growth covers the plants and the earth in damp, close and warm weather; damp and close vaults and rooms are filled with rank putridity, which disappears with vigorous circulation of the same confined air. The agitation of the water with air, the impregnation of the sickly wine with the atmospheric oxygen while in rapid motion, indicate to us the mode of preventing putrefaction. The lungs of our system serve a similar purpose. The lesson taught us by facts like these may be condensed in a few words. Surface contact of organic substances with stagnant, confined or slowly-moving air, favors destructive putrefactive organisms; but intimate contact with rapidly-moving air opposes putrefaction and decay, and promotes preservation.

Rapidly-moving air, nature's purifier, is constantly at our service, by employing suitable mechanical means to force the air into rapid motion;, and thus we are enabled to produce the purifying effects at will, which we observe nature to perform by this agent. To apply this principle for the effective and reliable purification of water, an indispensable condition is, that the rapidly-moving air should act uniformly upon all parts (not only upon the surface) of the water. Considerations as to best results at the least expense of labor, money, complication of machinery, etc, must determine the adoption of the method best suited to the practical operations.

Not only are the nitrogenous (detrimental) particles of organic matter in the water rapidly oxidized by this treatment properly conducted, but the low organisms in it and their germs are injuriously affected, their vitality destroyed, or so greatly impaired that many hours or days pass before decomposition (caused by low organisms) appear again, if at all, after the water has been thoroughly subjected to this treatment.