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S. F. Peckham on the Distillation of Hydrocarbons. 11 
Percentage results of Distillation under Pressure. 
umber I, H, TII. ry, 
N 
Volatile impurity, consisting of air and water,.... 1... sc... .--. 12°5 
Ist. Pres Distillation of crude material, 91— 87°66 82°86 72-20 
Coke and loss at do., 9— 12°34 17°34 15°50 
Ist Fractionation of sp. gr. 43° B. = °810, -....-- 42-— 56°72 40°33 16-70 
Leaving Heavy Residue for re-distillation, 49— 30°94 42°33 55:30 
Which yielded, by 2d Pressure Distillation,..-..-- 44°15 27°84 58°09 49°80 
2d. Fractionation of sp. gr. 43° B. == °810, -....-- 12°25 696 9°52 12°40 
Total crude Nluminating Oil, 54°25 62°68 49°35 2910 
Loss in treatment of do., ;35, 16 ; ‘49 ‘ 
Total yield of Refined Oil 51°25 60°70 48°36 23:20 
tal crude Lubricating Oil, 31°85 20°88 28°57 37:40 
oss in treatment of do., 734, “95 “62 “85 I 
Total Refined Lubricating Oil, 30:90 20:26 27°72 36°30 
Yield of Refined Mluminating Oil, sp. gr. 43° B.,-. 51°25 60°70 4836 28-20 
Yield of Refined Lubricating Oil, sp. gr. 23°-25°B., 30°90 20°26 27-72 36°30 
Loss in treatment, 2°61 250. 2°34. 2°00 
Coke and loss in Distillation, 18°24 16°54 21°58 33°50 
Yield of Tiluminating Oil by ordinary process,...-. 15°00 20°00 3:00 2:50 
Dr, Hirsch criticises these experiments as not being executed 
under circumstances “parallel to the distillation on a large 
scale.” He then states, that during the distillation of hydro- 
carbons on the large scale, “the process of ‘cracking’ always 
takes place in some degree,” as “‘all hydrocarbons o high 
stills now being introduced, “cracking” takes place without 
any ‘special efforts” to produce such a result, - while only a 
small portion distills over as paraffine oil, that being due fo 
‘over-heating.” He next states, that by rapid distillation of a 
small quantity, the different hydrocarbons which make up the 
petroleum come over unchanged, and that the difference be- 
tween this last named distillation and the former, is the same 
as the one between distilling coal for the production of illum- 
inating gas, and that for producing coal oil ; the former pro- 
one a dense tar, being carried a in small -S pt <= 
e latter, in revolving retorts of large capacity. ese 
the oily vapors are Banned to a cooler temperature than their — 
own with every revolution of the retort, and are in this manner 
broken up into oils of lighter gravity.” face 
