200 TRANSACTIONS OF THE 
oil with a light solvent, measuring the amount of water 
distilled, and applying this percentage as a correction to 
the total oil produced. 
The oil is also examined to determine percentages of 
nitrogen and sulphur, as these indicate, to a certain extent, 
the suitability of the oil for refining or direct use. It may 
be said, as a general rule, that the presence of sulphur 
or nitrogen in shale-oil is not desirable. 
The quality of a shale-oil can be best determined by 
subjecting it to a fractional analytical distillation, and 
examining the fractions so made. 
The method in use in the oil-shale laboratories of the 
Bureau of Mines for the analytical distillation of shale-oil 
and petroleum has been developed, with the exception of 
minor details, by Dr. E. W. Dean, petroleum chemist of 
the Bureau, and has been described by him in various 
publications. Bulletin 209 of the Bureau of Mines, by 
Dr. Dean, now in press, describes the distillation appara- 
tus and method in detail. Briefly, as applied to shale- 
oils, it is as follows: . 
The specific gravity of the oil is first taken, and as 
most shale oils are semi-solid at the temperature to which 
specific gravities of petroleum oils are referred (60°F), it 
is necessary to use a pycnometer or specific gravity bottle 
adapted for heavy oils or tars for this purpose. A low 
specific gravity ordinarily can be taken to mean that the 
oil contains a large percentage of paraffin hydrocarbons. 
The setting point of the oil is next taken. The setting 
point of the oil is that temperature at which a drop of oil 
frozen on the tip of a thermometer bulb melts and flows 
down the stem of the inverted thermometer. A high set- 
ting point is an indication of a high content of solid paraf- 
fin in the oil. Viscosity of the oil at a standard tempera- 
ture is next taken, and is of present value as an indication 
of the quality of the lubricating oil fractions, and in the 
future will be of value in making calculations of pipe lines 
for shale oils. 
The weight of 300 cubic centimeters of the oil is next 
calculated from its specific gravity and this quantity is 
placed in a standard fractionating flask. This flask is a 
round glass bulb from the top of which springs a vertical 
neck. Eight inches up the neck a side neck springs at 
