for technical analysis of Petroleum. } 233 
amount of distillate that I have seen recorded, as yielded by an 
material of undoubted natural origin, is ninety-five and diee half 
per cent, by measure.* The distillation of which this was the 
product was performed wholly in glass, without i Some the 
crude material being a California petroleum of medium density, 
yielding no permanent gases and no naphtha. In this case the 
loss may be estimated at zero. I think it will be readily con- 
ceded, that any apparatus which admits of the ready extraction 
of the coke, and at the same time yields an average of ninety - 
two and one-half per cent of distillate, furnishes results far more 
satisfactory than any hitherto in use for operating upon so small 
4 quantity as fifteen hundred cubic centimeters. : 
A thermometer may be inserted in the smaller orifice, for 
noting the temperature at which light oils distill. 
8as-pipe of the requisite size and about two inches in length 
_ may be used for making the connection, the thermometer being 
luted into one end of it. When but one of the openings in 
the retort is in use, the other may be closed with an iron Ping. 
‘1 making my experiments upon Young's process of distil- 
lation under pressure, I experienced much difficulty in contriving 
an apparatus that would enable me to register the amount of 
retort and U tube. : : 
I next tried a small valve constructed like an ordinary safety 
ly upon the spindle, the whole contained in a chamber 
resembling a scihstae steam-chest, from which the vapors could 
Y escape into the worm. It was found upon trial wit 
safety-valve that an orifice three-eighths of an inch in diameter 
Was too large in proportion to the size of the retort, the vee 
scaping in too large volume to admit of a continued flow 
the Worm. The vapor escaped in intermittent puffs, “A 
causing an undulatory movement from the requisite amount Of 
ure to no pressure at all. As a consequence, the resale: jal 
raed contained in an article on Petroleum in Cal- 
ita, By Prof B. Sinem Naticnsl Latelligencar, Feb. 7th, 1868. 
_ At. Jour. Sor.—Seconp Seares, Vou. XLIV, No. 151.—Serr., 1867. 
