1897.] PETROLEUM AND NATURAL GAS. 101 



were products of a slow fractional distillation. Prof. Newberry 

 speaks of black Devonian shales as the source of supply in this pro- 

 cess, while Prof. Peckham takes in both beds of shale and limestone 

 containing fucoids and animal remains as subjected to the distilla- 

 tion process. 



In concluding, I have a small contribution to offer to the experi- 

 mental data which bear upon the question of possible origin, and 

 upon which we can theorize as to conditions of formation. 



Engler, as already mentioned, distilled menhaden oil under 

 pressure, and afterwards extended his experiments to lard oil and 

 artificial oleins. From his results he is led to believe in the 

 exclusively animal origin of petroleum. I have found that linseed 

 oil, and presumably the other vegetable seed oils, may be made to 

 yield similar products, and have even obtained solid paraffine from 

 this source. While it has long been known that inflammable vapors 

 are given off when linseed oil is boiled for varnish making and 

 similar purposes, very little attempt has been made to collect and 

 study the composition of these vapors. Schaedler, in his exhaustive 

 work on the vegetable and animal oils, simply makes the statement 

 that small quantities of hydrocarbons are present in the vapors 

 resulting from this destructive distillation. 



Finding that in one case that came under my attention linseed 

 oil was being boiled for varnish making under pressure, and that 

 considerable quantities of a liquid distillate were being condensed 

 in the dome of the large still and returned to the body of the oil, 

 I arranged for the collection of these condensed vapors and col- 

 lected them for examination. 



At first the odor of acrolein was very pronounced and powerful, 

 showing that the glycerine of the glycerides composing the oil was 

 being decomposed ; later the odor was more that of a cracked 

 petroleum oil, showing that the linoleic and other acids of the oil 

 were undergoing decomposition. The raw distillate collected after 

 this acrolein odor had nearly disappeared, I found had a specific 

 gravity of 0.860 and had changed so thoroughly from the original 

 linseed oil that it showed a saponification equivalent of only 1.09, 

 indicating that it was mainly a neutral oil and presumably made up 

 largely of hydrocarbons. I might say here that I examined the 

 linseed oil which was used in this test. It was a clear " old pro- 

 cess " oil, of specific gravity 0.929, and showed a saponification 

 equivalent of 183, which is normal for linseed oil. 



PROC. AMER. PHILOS. SOC. XXXYI. 154. 11. PRINTED MAT 21, 1897. 



