RESEARCHES tJPON THE CHEMICAL PEOPERTlES OE CASES. 231 



water. The carbon dioxide produced would lessen the solubility of the water for 

 nitrogen by causing the water to dissolve carbonate of lime, etc. Gentle heat from 

 below would tend still further to the expulsion of the nitrogen, and thus a consider- 

 able but limited quantity of nitrogen might be obtained as a sudden outburst from 

 a di-ill hole. 



It may be said that varying conditions of temperature and pressure, and kind of 

 rock, have modified the products, so that perhaps the carbon monoxide and ethylene 

 resulting from a laboratory experiment have, in nature's workshop, given place to 

 paraffins. 



But, if the chemistry of the reaction supposed to occur is to be considered at 

 all, the fact that distillation experiments have produced from fish oil certain bodies 

 found in natural gas (paraffins), should not count more forcibly as geological evi- 

 dence than the other fact, that such distillation yields bodies which are foreign to 

 natural gas as usually found in Pennsylvania. 



I have failed to find any data tending to show that organic matter can be sub- 

 jected to destructive distillation in such a manner as not to yield carbon monoxide 

 and considerable quantities of olefines, together with hydrocarbons of still less sat- 

 urated character. As a I'ule, the acetylenes and benzol series appear. Engler's 

 hypothesis involves the supposition that a process of distillation has occurred at 

 moderately high temperatures and at pressures measured by great depth of rock 

 strata. The carbon dioxide evolved in this destructive distillation must have come 

 continuously into contact with the vast quantities of carbon, which in its various 

 stages of transformation from vegetable tissue to anthracite is so widely distributed 

 throughout the rocks. The reaction CO2 + C = 2 CO, which proceeds rapidly at a 

 strong heat and also slowly at lower temperatures, would then probably have oc- 

 curred, wherever the temperature was sufficiently high. 



Prolonged contact of carbon dioxide with the carbonaceous residue of the dis- 

 tillation would perhaps be sufficient to increase considerably the final yield of carbon 

 monoxide. 



According to I. L. Bell (^Chemical Principles of the Manufacture of Iron and 

 Steely p. 101) the reduction of carbon dioxide to carbon monoxide by carbon in the 

 form of soft coke begins at 427° C. 



This is about the temperature at which Engler's distillation experiments were 

 conducted (360°-420° C). 



Engler has shown that distillation of animal fats at very high pressure (25 at- 

 mospheres) may yield gas containing less of carbon monoxide and olefines than 

 when the process is conducted under atmospheric pressure. N^o data are at hand as 



