216 TRANSACTIONS OF THE 
remove the causes of decomposition outlined in the pre- 
ceding paragraphs. Another alternative will accomplish 
the same results as increased retorting time, that is, the 
grinding of the shale extremely fine and thereby reduc- 
ing the depth for heat penetration in the individual 
shale particle. This could actually cause the pyrolysis 
practically to become a surface reaction. This expedi- 
ent has its economic objections also, but for the sake of 
research possibilities, it offers an opportunity to elimin- 
ate many of the deleterious factors of retorting, the 
extent of whose importance is not yet fully known. 
The oil-shale assay retort which was developed by 
Mr. L. A. Anderson, “Research Fellow’, University of- 
Utah, in cooperation with the writer was designed for 
extreme accuracy in quantitative determinations of oil 
yield, and to produce oil of good quality. The dimen- 
sions of the shale container, which is a pint capacity 
amalgam retort, are small in order to minimize the dis- 
tance for the heat to penetrate. The time for comple- 
tion of a retorting test is only four hours when treating 
the richest shale. The method of operating the retort 
requires that the shale used be ground to minus one- 
quarter inch size. The result is that during the distilla- 
tion, in no piece of shale will the vapors have to travel 
more than one-eighth of an inch, (one-half the thickness 
of the shale granules), toward the source of heat, before 
reversing their direction and moving into a cooler zone 
and thence to the exit. The vapors from the finer shale 
particles will move a much shorter direction toward the 
source of heat before reversing direction. Variations in 
rate of retorting are employed in order to study the dif- 
ferent properties of oil produced. 
When shale is retorted very slowly and there are 
no means provided for scavenging, the gases and vapors 
tend to stagnate within the retort and are thus subjected 
to prolonged pyrolytic effects resulting in much decom- 
position. The Scotch process uses lumps of shale the 
size of building bricks and consequently the shale is 
allowed eight hours in which to complete distillation. 
Under this condition of a long period of heating, there 
would be ample time for much decomposition of the 
