6o NEW YORK STATE MUSEUM 



We may now direct special attention to the carbonic acid gas. 

 There are four ways in which carbonic acid is produced in nature.^ 

 The simplest is by the direct oxidation of carbonaceous deposits, 

 such as peat bogs, coal seams, and the like. It is one of the danger- 

 ous gases in coal mines, constituting the choke damp of the miner. 

 We have no reason to believe, however, in the existence of car- 

 bonaceous beds of this sort beneath Saratoga and much reason to 

 infer their absence. The second method is by the action of some 

 free acid such as sulfuric upon limestone. Sulfuric acid is some- 

 times produced in nature by the oxidation of pyrites, in the presence 

 of water. If it meets with limestone it destroys the carbonate of 

 lime, evolving carbonic acid gas and forming calcium sulphate. 

 Since hydrated calcium sulphate is the mineral gypsum, gypsum 

 beds have been sometimes explained in this w^ay. We have no 

 reason to infer gypsum beds beneath Saratoga, nor do we find in 

 the waters the calcium sulphate which would be demanded by this 

 reaction. We may dismiss this explanation also. 



The third method of formation is by the silicification of lime- 

 stone. Silicic acid in solution, especially around the borders of still 

 heated masses of igneous rock^ displaces the carbonic acid of calcium 

 carbonate and forms calcium silicates. The carbonic acid then 

 migrates. It is possible that some such process as this deep down 

 in the Grenville strata either has taken place or is taking place 

 and that the gas thus liberated is still rising to the surface or has 

 risen and now remains in solution in the waters. 



The last and most important explanation of free carbonic acid 

 as it is met in foreign localities, is based on expiring volcanic or 

 igneous action. It is a matter of observation that the copious 

 emission of the gas is one of the characteristic features of volcanoes 

 which are no longer active. As time passes the zone of gas emis- 

 sion appears to widen around them until it finally ceases. The 

 amount furnished is in instances prodigious. One borehole at 

 Sondra in Thuringia, Germany, 197 meters deep, yields daily at a 

 pressure of about 230 pounds to the inch, over 500,000 kilos, or 

 over 1,000,000 pounds of the gas. At another place, Oberlandstein, 

 6,000,000 litres in 24 hours are obtained, or 20,000 pounds of the 

 gas.- The utilization of the gas is the basis of an important indus- 

 try in Germany and supports a special journal. 



1 An excellent general summary of the geology of carbonic acid gas 

 is a paper by Rudolph Delkeskamp, Vadose and Juvenile Kohlensaure. 

 Zeitschrift f. prakt. Geologic, Feb. 6, 1906, p. 33. 



2 N. Wender. Die Kohlensaure-industrie, Berlin, 1901, p. 72-73. 



