236 TRANSACTIONS OF THE 
Exact data regarding the action of steam or air upon 
incandescent spent shale are not available at this time, 
but the effects of each upon carbon, coal and coke, are 
known. The amount of carbon monoxide and hydrogen 
formed from each of these substances, at a given temper- 
ature, depends largely upon the time of contact. Under 
similar conditions and during equal intervals of time, the 
percentage of carbon monoxide formed from coke is less 
than that from charcoal, while the percentage formed 
from anthracite coal is less than that formed from coke. 
It will be noted that the surface exposed to the action of 
the gases is greatest in charcoal, less in the case of coke, 
and least in anthracite. Where the time of contact is 
great enough to allow equilibrium to be reached in the 
reaction, the percentage of carbon monoxide formed is 
practically the same in every case. When superheated 
steam is passed through incandescent carbon, the com- 
position of the gas obtained as well as the quantity of 
steam decomposed in a given time depends largely upon 
the temperature, rate of flow or time of contact, and the 
nature of the carbon. Practically 100 percent of the 
water vapor can be decomposed at a temperature of 
1100°C. where the time of contact is great enough. 
Investigations indicate that the fixed carbon content 
of American oil-shales varies from less than three to 
possibly 28 per cent; the average for most average Ameri- 
can shales varying from 7 to 9 percent, and this amount, 
together with the uncondensible hydrocarbon gases will, 
in most cases, be sufficient to furnish fuel for the retorting 
process, if the retort is of average thermal efficiency. 
The amount of ammonia recovered during the retort- 
ing process seems to depend almost directly, up to a 
certain quantity, upon the amount of steam used. Exper- 
iments indicate that as high as ninety-five percent of the 
total nitrogen content of a shale can be recovered as 
ammonia by the use of proper amounts of steam at correct 
temperatures. In the Scotch retort about sixty percent 
of the nitrogen in the shale is recovered as ammonium- 
sulphate under their conditions of operation. 
The fifth purpose enumerated: to add greater volume 
to the vapors, is an important function of the steam. 
