"Imitations of mineral spring waters are made by dissolving the salts which constitute the bases of the natural mineral waters in distilled or ordinary water, impregnated with gases, especially carbonic acid gas. Experiments in their manufacture were made as early as the sixteenth century, but they have been produced in perfection only within the past fifty years, since chemical analysis has become an operation of minute exactness. The merit of the discovery of their principles belongs to Berzelius and the German physician, Struve; but the latter, who proved the practical value of the invention, and founded (as Berzelius did in Stockholm) the first manufactories or spas in Dresden (1818-20), Leipsic, Hamburg, Berlin, St. Petersburg, and Brighton, is deservedly called the father of artificial mineral waters. By powdering the clinkstone of Bilin, and subjecting it to the action of carbonic-acid water, under a slight hydrostatic pressure, he produced a mineral water identical with that of the natural spring ot Bilin. Faraday and Liebig pronounced his artificial Carlsbad and Friedrichshall bitter waters to be identical in chemical composition and physiological action with the natural waters which they represented. Artificial mineral waters have some advantages over natural waters. The supply of the latter, exported from the springs of Continental Europe, is inadequate to the demand, and most natural waters lose materially by bottling. The springs, too, are subject to many changes, and frequently vary in the quantity or relative proportion of their mineral ingredients. .Artificial waters, on the contrary, are prepared according to analysis, which represent the natural mineral waters when in their best condition. They are always the same in composition, in consequence of the technical perfection of their manufacture; and they produce the same general effect as the natural waters. They are more highly charged with carbonic acid gas than the latter, which ensures their keeping in any climate, and renders them more pleasant to the taste. The manufacture of mineral waters also embraces composition waters, devised for special medical purposes, and the beverages 'Soda water' and 'Seltzer water' The most important constituent of all these waters is carbonic acid gas, which is prepared by decomposing carbonates of lime and bi-carbonates of soda with acids, especially sulphuric acid, in a vessel called the generator". The above, from the American Cyclopaedia, we think very valuable.

The large and real influence which free carbonic acid exercises upon the composition of natural mineral waters, Struve has not only noticed in the long course of his investigations of natural mineral waters, but also demonstrated and proved scientifically that the free carbonic acid when combined with water, and particularly under a great pressure, washes and partly decomposes or dissolves a number of the compound minerals.

Carbonic acid at first only serves as a dissolvent in the fabrication, and afterwards as a preservative of mineral waters. As a resolvent to a number of substances which are dissolved with difficulty, or which are entirely insoluble in water which contains no carbonic acid, such as the carbonates of protoxide of manganese, of protoxide of iron, and the combinations of carbonic acid and phosphoric acid with magnesia and akaline earths. As a preservative in two ways: it throws off the atmospheric air contained, and prevents the access of air, since the water is saturated under high pressure of this gas. The rare intelligence of Struve soon found that the alteration of natural mineral waters was caused by atmospheric air introduced during the bottling process, or by that which mixes with it afterwards.

The influence of oxygen upon the ferruginous (and manganesian) springs is principally evident, and there are but few not ferruginous.

Iron and manganese are found in the state of oxydulated carbonates, soluble by the action of free carbonic acid; when carbonic acid, which is found in springs only in small quantities, is eliminated, the combination, in absorbing the oxygen in atmospheric air, is changed into oxide, which is separated and precipitated, and can no more be dissolved, not even by the aid of larger quantities of carbonic acid. This elimination is produced the quicker the higher the temperature of the water is. Thus, the Carlsbad sprudel, which rises to a temperature of 73.75° C, is soon covered with a coating of oxide of iron of a yellow and ochre color, while the Carls-bad springs, composed throughout of the same substances, at a lower temperature, however, such as 56.25° and 50° C, show the same separation, but after a greater length of time and then in much lower degree. In all cold springs with iron as a constituent, this phenomena occurs oftentimes after the lapse of several hours.

Not only the hot springs, but also cold ferruginous ones, such as Marienbad, Kissingen and Pyrmont, are subject to alteration by the more or less separation of the iron during the bottling process, or while in storage, which is then found soon in dark flakes, as a clayey turbidity or as an ochre deposit clinging to the sides of the bottles or keeping suspended in the liquid. These deposits, which cannot escape the eyes of the most inattentive observer, and the very insignificant taste of iron compared with that of the water freshly drawn, sufficiently proves the always very considerable loss or separation of the iron, the good effects of which are principally intended. The natural mineral waters often contain free oxygen in solution, which, even when they are bottled, and in spite of all care taken, converts the oxydulated iron into oxide and separates it. From the researches of A. Husemann, it is shown that the quicker this is done the more diminutive the quantity of organic substances in water that is capable of absorbing the free oxygen. (See Dr. Hirsch's "Die Fabrication der Kunstlichen Mineral Wasser".)

We have appended later on remedies or preservatives for ferruginous water, and shall refer especially to Husemann's experiments.

The science of chemistry has accomplished much more in imitating the natural mineral waters than the casual observer gives it credit for. After chemistry had developed, by analysis, the composition of mineral waters, it at once led to their preparation artificially, and if they can be imitated, they may also be improved upon. For instance, some mineral waters may contain ingredients which are healthful, in such small quantities as to have their virtue unfelt, while at the same time ingredients of a noxious kind may exist in larger proportions. In imitating such curative waters, the chemist can add to the one and take from the other, and thus improve on nature itself. Again, while the natural water is subject to changes of temperature, to occasional subterranean action, to a more or less rapid flow, or other causes tending to change its character and efficiency, chemistry insures a perfectly regular and reliable compound of all its ingredients at all times, and all that is required is, that this compound be properly carbonated with pure gas, and suffering humanity have no occasion to visit the "springs" for the benefits derived from the use of any particular natural mineral waters.

Of course much depends on the carbonic acid gas with which these artificial waters are impregnated. This being properly done, the resu': cannot fail to be an improvement on the natural water, which may have been transported by land and sea from springs three or four thousand miles away. The practical carbonator can bring the science of compounding artificial waters to so high a state of perfection, that it may fully compete with the imported articles. All that is needed to bring about this result is, that the preparation of the artificial be left in the hands of responsible, practical manufacturers of carbonic acid gas waters, not such as follow old "formulas" or "theories," copied from cook books and family recipes of their grandfathers, and make a stuff which, instead of the mild, soft and pungent taste of the genuine, produced by effectual carbonation, tastes just like any other salt water.

Artificial mineral waters must always have a quite certain combination, and should be prepared only with water which has been purified by distillation, and freed especially from solid matters and ammonia.

It is also important to the mineral-water manufacturer that the water should not contain an excessive amount of iron, in case well or spring water is used, that is in other respects regarded pure, as this metal has a very deleterious action upon other constituents.

Distilled water alone should be employed in the manufacture of artificial mineral waters freed from organic matter and from atmospheric air. The latter expelled in the manner explained before.

Where other pure waters are used in their composition they should be first boiled and allowed to cool out of contact with the air, especially for chalybeated and sulphuretted waters.

In addition to the analyses appended hereafter, it may be remarked that in some springs but traces of iodine, bromine, both single or combined, also manganese, phosphoric acid, etc., have been found in some natural mineral waters. It is the opinion of many high authorities that the medicinal virtues of these waters depend more on the minute quantities of the above substances, and the high state of dilution in which they are held, than on their more abundant saline ingredients.