The American Carbonate Company, lately instituted in New York, gives in its circular the following explanation to the trade, which we copy, being of interest to those intending to give liquid carbonic acid a trial. It says:

"The acid is bottled in wrought-iron cylinders (see cut in Part III, on Apparatus), tested to stand a four-fold higher pressure than they are ordinarily required to bear, so that the acid can be handled and shipped in these cylinders at any time of the year and in all climates with absolute safety. Each cylinder is about 4 feet long and 5 inches in diameter and holds about twenty pounds of liquid carbonic acid, which represents about eleven hundred gallons of carbonic acid gas at the common atmospheric pressure. By this immense condensation in volume the saving in transportation, the ready supply and the easy application is correspondingly great. All that is required to obtain the desired amount of carbonic acid for immediate use is to open the valve of the cylinder, when by evaporation of the liquid the gas will escape till the valve is closed or the bottle emptied. These cylinders when charged are perfectly harmless, and in case of accidental breakage the only result would be the gradual escape of the carbonate in its gaseous state.

" The carbonate of this company is not only absolutely pure, and therefore better adapted for the charging of carbonated beverages, but is also cheaper than the gas produced by the old method. Each of our cylinders of twenty pounds of gas by weight is sufficient to charge two hundred to three hundred gallons of pure water, according to the pressure desired. As the evaporation of the liquid acid into its gaseous state absorbs warmth, and consequently produces cold, the absorption of the extremely cold gas by the water is much more rapid and complete at a comparatively lower pressure and in a much shorter time than by the old method. By using the carbonic acid gas in the form manufactured by this company for the purpose of charging beverages there will be consequently a great saving in material, apparatus, help for handling and time, this materially reducing the cost of manufacturing these beverages.

"Liquid carbonic acid is also used to great advantage in drawing beer, ales, porter, etc. By its use the old methods of forcing beer by water or air pressure is not only superseded, but the beer is kept in a uniform excellent condition for any length of time, and the last drop in the barrel will be as fresh and healthy as the first glass.

"In breweries it can be used for clearing beer; in bakeries it takes the place of yeast and artificial baking powders, all of which are more or less injurious. It is also extensively used in apparatus for extinguishing fires; for cooling purposes; in the manufacture of cast steel and other cast metals; for raising sunken wrecks, and for many other manufacturing, mechanical and scientific purposes".

The company offers also a series of apparatus for distributing and applying the gas, for regulating its escape and measuring its pressure. A description of them we will find in the next Part, on Apparatus, with a report appended as to their practical employment, by the writer's own experience and experiments.