impregnating Mineral Waters with Carbonic Acid. 
cence. The vessel V, containing 16 gallons, maybe formed either 
of copper tinned, with an agitator of the same metal, or of cast- 
iron lined with 6 or 8 lb. of lead, and an agitator of maple-* 
wood, which gives no taste to the w'ater. It is filled to the dot- 
ted line with water, and a proportional quantity of carbonate 
of soda, magnesia, or other substance, to be impregnated. T is 
a pressure-gauge, containing mercury ; in the figure it is placed 
on the top of the vessel, but it is more convenient to place it at 
a little distance, forming a communication by a pipe. The com-^ 
municating pipes are lead, and their several uses are distinctly 
evident in the figure. When the vessels are filled, the mode of 
operation is extremely simple. On turning the nut M, the sul- 
phuric acid is allowed to come into contact with the whitening ; 
carbonic acid is necessarily disengaged, and in quantity and ra- 
pidity proportional to the quantity of sulphuric acid let down. 
If the vessels were sufficiently capacious, 10,000 gallons of 
carbonic acid could be instantaneously produced. But by the 
alternate turning of the nut M, the sulphuric acid is allowed to 
fall down in small portions, which regulates the disengagement 
of the gas, and prevents too great an effervescence. As the gas 
is still accumulating, having no way to escape, it passes over 
into the vessel V, and is there absorbed by the water. In this 
way a pressure from 20 to 30 atmospheres may be thrown into 
the vessels. It must therefore be obvious to every man of science, 
that if the vessel A were connected by a pipe, with the valves of 
an engine somewhat similar to a steam-engine, the vast pres- 
sure, which can be so instantaneously produced, would raise and 
depress alternately the piston of a cylinder: That cylinder, 
too, would only require to be g’^th the diameter of the steam- 
cylinder to have an equivalent power ; and the gas would be 
reduced to one atmosphere by its alternate escape at the oppo- 
site valves, no water being required for condensation. But, un- 
fortunately, the expence of sulphuric acid, from the quantity 
required (when the gas is allowed to escape), presents an unsur- 
mountable obstacle as a substitute for the steam-engine. Since 
I discovered the power, from the production of carbonic acid, 
and put it into practice four years ago, an account of which was 
noticed in most of the journals and newspapers of the day, I 
am happy to observe, that that distinguished ornament of our’ 
a2 
