S. F. Peckham on the Distillation of Hydrocarbons. 9 
Art. Il.—On the distillation of dense Hydrocarbons at high 
temperatures, technically termed ‘‘ Cracking;” by 8. F. 
PECKHAM, 
In the American reprint of the Chemical News, for June of 
this year, an article appears “On Naphtha and Hluminating 
Oil from heavy California Tar,” by Prof. B. Silliman, copied 
from the San Francisco Bulletin. In the September number 
of the same journal, an article appears “On the Distillation of 
Hydrocarbons,” by Joseph Hirsch, Ph.D., in which the results 
obtained by Prof. 8. are subjected to critigism, and certain 
statements made in reference to the subject of a most extraor- 
dinary character. 
At the same time that Mr, Corning was engaged upon the 
experiments, the results of which form the subject of Prof. 
illiman’s paper, I was engaged upon experiments of a similar 
character for the Geological Survey otf California, the results 
of which have not yet been published.* These results differed 
somewhat from those obtained by Prof. §., as also the method 
by which they were obtained. I shall, therefore, give a brief 
summary, both of method and results, and compare the conclu- 
sions to be derived from them with. the statements made by 
. Hirsch. 
crude material at my command (5 gallons of each variety) 
rendered this operation exceedingly difficult to conduct suc- 
* The volume of Reports of the Survey on “Economical Geology,” containing 
these , is now ready for the press, but its publication is delayed by the 
failure of the last California Legislature in making the necessary appropriation. 
