40 NEW YORK STATE MUSEUM 



Ten cubic feet of COo, at ordinary temperatures and pressures, 

 weigh practically one pound, so that one cubic foot is about .i of a 

 pound. If the specific gravity of air be taken as i.o, CO2 is 1.529. 

 A liter of air weighs 1.293 grams, and a Hter of CO2 weighs 1.976. 

 Gases are of course very sensitive to changes of temperature and 

 pressure, and therefore in very accurate statements both have to be 

 mentioned, but without going into too great refinements the above 

 figures will answer for ordinary temperatures and pressures. 



Since a gallon is 231 cubic inches, or .1337 of a cubic foot, a 

 gallon of CO2 weighs .01337 pounds or, as there are 7000 grains in 

 a pound, about 93.6 grains. Where analyses are expressed in 

 grains per gallon, and CO2 is reported (as in the Chandler series) 

 both as total CO2, and as CO2 in carbonates and bicarbonates, we can 

 easily obtain the free gas by subtracting the latter from the former. 

 If we then divide the free CO2 expressed in grains by 93.6 we 

 change it over to volumes. The necessary, data are given in the 

 Chandler series. In the analyses from the Department of Agri- 

 culture, the data are given in the thirteen analyses of samples taken 

 directly at the springs. Since they are expressed in cubic centi- 

 meters per liter they read off directly in volumes, but it is obvious 

 from the figures that they do not represent the total gas that 

 reaches the surface with the waters. 



The best guide to the amount of carbonic acid gas emerging with 

 the mineral waters is furnished by the experience of the gas com- 

 panies. The richest in gas was found to be the Adams well of the 

 New York Company now the General Carbonic Company. It 

 yielded five volumes of the gas leaving one volume in solution. The 

 general average, however, was two or three. 



THE WATER SEAL 



Under the general topic of carbonic acid gas, note may be made of 

 a very curious phenomenon connected with the natural flowing 

 springs which have been drilled and cased. If even in the most 

 gaseous one the top of the casing be covered tightly so as to prevent 

 the escape of the water and gas, and if the tight cover be main- 

 tained in this condition long enough to permit all the free gas to rise 

 and collect immediately beneath it so that the well becomes quiet, 

 the well will not resume its flow on removing the obstruction. It 

 must be artificially started with a pump. The phenomenon is called 

 the ivater seal, since the spring is, as it were, sealed off by water. 



The explanation lies in the following relationship of the solubility 

 of carbonic acid gas to the pressure under which the water stands 



