206 
OIL DISTRICTS OF SOUTHERN CALIFORNIA. 
reason it is considered proper to give the following description of the methods by which 
the data in the above table were determined. * 
Specific gravity .—Two pycnometers were used, one holding 25 c. c. and the other 1^ 
c. c., the larger one for the light oils and the smaller for the heavy oils. Both were 
calibrated with pure distilled water and the water content calculated to 4°. A heavy 
oil may be introduced into either pycnometer by first filling a small beaker and allow¬ 
ing a very small drop to fall into the pycnometer. This drop will carry with it a thread 
of oil, which may be increased to a stream, and thus the pycnometer can be filled with¬ 
out getting any air bubbles mixed with the oil. If the oil once touches the side of the 
neck it is an interminable job to fill the instrument. It would be better to clean out 
with gasoline and start over again. If the oil is too thick to pour, as above, then use 
the little pycnometer, which is nothing more than a little bottle with a wide neck and 
a glass stopper carefully ground in. The little bottle is put next to the lip of the beaker 
containing the sample and the oil allowed to drain in. If the draining takes place 
slowly no air will get mixed with the oil. Then the stopper is slowly squeezed in, 
until by turning it, it grates on the ground glass of the bottle. The excess oil is wiped 
off with a rag, without undue handling of the bottle with the fingers. After weighing, 
the temperature is taken with an accurate thermometer and a correction of 0.0006 in 
specific gravity made for heavy oils and 0.0007 for light oils for each degree centigrade 
variation from 15°—15° being taken as normal. 
Example: The little pycnometer full of sample No. 31 weighs 6.6195 at 18.5°. 
6.6195 wt. of pycnometer and oil. 
4.8413 wt. of pycnometer. 
1.7782 wt. of oil in pycnometer. 
1.7782 (wt. of oil) 1.8431 (wt. of water) = .9648. 
.9648 + (3| X .0006) = .9669 sp. g. of No. 31 at 15°. 
This seems a long process, but it is quickly carried out. I made 16 specific-gravity 
determinations in four hours, or an average of 1 in fifteen minutes. An error in the 
specific gravity causes a corresponding error in the distillation and also in the calorific 
value per c. c., and too much care can not be taken in its determination. To take 
the gravity of heavy oils by the hydrometer is as long as this, and, moreover, very inac¬ 
curate. On first consideration it might seem that the specific gravity taken in a little 
bottle as small as 1.5 c. c. would be inaccurate, but I compared this with the 25 c. c. 
pycnometer and obtained results agreeing to 0.0001 in specific gravity, or practically 
identical. 
Viscosity .—There are many viscometers, but none of them are ideal. Nevertheless, 
I could not invent one that would answer all requirements and expect the public to 
use it. It takes time to introduce a new idea or instrument. The Redwood viscom¬ 
eter seems to me to be the best now on the market, for the following reasons: It is the 
English standard; the tip is made of agate, and so will not wear out; the tip is sur¬ 
rounded by heavy brass, thus keeping the oil in the tip at approximately the same 
temperature as the oil in the cup. 
In the above data the viscosity has been taken at two temperatures—at 15° C. (about 
60° F.) and at 85° C. (185° F.). It was taken at 15° C. because this is generally taken 
as “ordinary temperature,” and at 85° C. because it is impossible to heat the contents 
of the Redwood viscometer up to 100° C. (212° F.) with boiling water, so some lower 
temperature must be chosen. It is easy to heat the instrument up to 85° C. (185° F.), 
and, moreover, a pipe line may be heated to 85° C., but with great difficulty higher 
than this. Since our main object in finding the viscosity is to ascertain whether the 
oil can be piped without too great cost for pumping, the last consideration is important. 
To see whether it is practical to pass the oil through pipes 85° C. has been chosen. 
It is customary to give the results in the number of seconds that it takes 50 c. c. to run 
through the instrument. To compare this with water (which runs through in 25 sec- 
