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B, Silliman on Illuminating Oil from California Tar. 243 
tillation of so dense a body. The experiments were conducted 
on quantities of from five to ten gallons each. The crude oi 
was very dark, almost black, transmitting yellow brown light in 
thin films. At ordinary temperatures (60° F.) it is a thick, viscid 
liquid, resembling coal tar, but with only a very slight odor. 
Its density at 60° F. is 0:980 or 13° Baumé. It retains, me- 
chanically entangled, a considerable quantity of water, which is 
neutral in its reaction. The odor of sulphydric acid, which is 
very decided in this product, as I have noted in its locality, had 
entirely disappeared in the specimen under consideration. 
The tar froths at the commencement of distillation, from escape 
of watery vapor. It yields by a primary distillation no product 
having a less density than 0°844, or 87° B. at 52° F. 
Distillation to dryness produced in two trials an average re- 
sult as follows: 
Oil having a density of 890 to 0°900, - - 69°82 
oke, water, and loss, - - - - - 30°18 
100-00 
In one of these trials the product was divided as follows: 
Oil, of density 29° B. at 52° (*885 sp. os - 
“ “ 94°75 “ 58° (908 “ 4 a 17°5 
. - 32°5 
100°0 
The coke is very large in quantity, strong, and is a good fuel, 
resembling gas-house coke. The odor of ammonia is given off 
Coke, water, loss, &., - - 
_ toward the close of the distillation. 
It is well known to distillers of petroleum that by the process 
called “cracking,” heavy oils unfit for illumination are broken 
up into bodies of less density, from light naphtha to the heavier 
illuminating and lubricating oils. This process is simply the 
application of a carefully regulated heat producing a slow distil- 
tion. By this treatment the molecules apparently rearrange 
themselves into groups of different density, whic a subse- 
aera distillation are divided into fractions (or heaps” as Mr. 
arren calls them) of tolerably constant boiling points. 
about ‘885 at 6 1° Baumé lower than before distilla- 
tion, A eatment with sulphuric acid and 
tilling from soda, it hada density of ‘880 at 60° F. Upon re- 
distilling, 100 measures of this last distillate yielded — 
Light oil having a density of about 834 at 60° F,, 2158 
Heavy a “ “ “ “880 “ 66° Bu Sh 41: 
eas m —. 8 » 6% eee 34°53 
Celie tig o8 ie + ee gee ae ee. 
