* 
S. F. Peckham on the Distillation of Hydrocarbons. 13 
Pp 
only 1,500 cubic centimeters at a time. 
Dr. Hirsch is correct in stating that during the distillation on 
ee, but his reasoning is utterly at fault. So, too, is his ex- 
planation of the fact, that “cracking” takes place in large 
and radiation, With such an arrangement it is impossible, 
upon Mr, Downer’s plan, to prevent more or less condensation 
upon the dome, and consequent “cracking,” especially toward 
the end of the operation, in stills of the enormous capacity 
of 40,000 gallons, where all the conditions essential to his pro- 
cess are present. It was in stills set in this manner that the 
heavy California oils were first distilled, and in which they were 
“cracked” to an oil of medium density; but when the sides 
and domes of the stills were surrounded with brick-work, the 
vapors were no longer condensed, and they passed unchanged 
- into the receiver. 
Dr, Hirsch is again in error, in supposing that paraffine oils 
are produced by a high temperature. I am_ told that Mr. 
products at the very lowest temperature possible. see 
He is yet again in error, in the analogy which he assumes 
to exist between rapid and slow distillation of petroleum, and 
the distillation of coals, in small retorts to produce illumin- 
ating gas, and in revolving retorts to produce oil. Rapid dis- 
tillation “cracks” the oil, se it necessitates i 
