178 EXAMINATION OF A NAPHTHA FROM LIME-SOAP. 
over; but in the still employed, which was of the ordinary pot-shape, the operation was 
somewhat tedious, on account of the difficulty of heating the interior of so large a mass 
of lime. Portions of the products of distillation also condensed at first in the upper 
layers of the lime, and were driven off with difficulty. Both these impediments could 
however undoubtedly have been avoided by employing a common iron gas-retort in- 
stead of the still. 
As a distillate there was obtained a mixture of hydro-carbon oils, of a dark brown 
color, and a peculiar, disagreeable odor. In consistency this mixture did not differ 
much from the crude coal-oil which is obtained by distilling rich cannel-coals. The 
distillate in question came over mixed with some water, which, however, immediately 
separated as a layer beneath the oil. 
The calcareous residuum in the retort was usually colored more or less strongly with 
carbonaceous matter. 
The crude hydro-carbon oil was rectified by first distilling it in a slow current of 
steam, then treating the distillate successively with oil of vitriol and a solution of caus- 
tic soda in the usual way, and again distilling in steam, as before. The refined product: 
so closely resembled refined coal-oil and petroleum in odor, color, and illuminating prop- 
erties, that it could hardly be distinguished from these. 
The yield of refined, merchantable hydro-carbon oil amounted to 60 % or more of 
the menhaden-oil from which it was derived. Refined coal-oil was at that time selling 
for $1 to $1.25 per gallon, while the cost of the menhaden-oil was only 25 cents per 
gallon. But the discovery of petroleum in Pennsylvania, that is, of the method of ob- 
taining petroleum by boring, of course destroyed the technical value of these results. 
The residuum of the first rectification of the crude oil was a thick grease, from which 
large quantities of a colorless crystalline compound were easily separated; but of this 
solid matter we have as yet made no examination. 
Preparation and Investigation of the Naphtha. 
The naphtha which we have subjected to particular examination, and of which alone 
we propose to speak in the following memoir, was obtained from the crude hydro-car- 
bon oil above described, as follows: After having stood enclosed in air-tight iron tanks 
during four years, that is, until the autumn of 1863, a part of the crude oil which had 
undergone no preliminary treatment whatsoever, was subjected to the process of distilla- 
tion, and fractional condensation devised by one of us, which is described in detail in 
the ninth volume of the memoirs of this Academy.* 
* Warren, Memoirs of American Academy, [N. S.] IX. 121. 
