21,1 Cole: Manufacture of Industrial Alcohol 293 
assumed practical importance. This is due to the enormous 
increase in the use of automobiles in the last decade and the 
world-wide application of crude oil to transportation. The 
powers of the world are even now engaged in a struggle to 
monopolize the available supplies of crude oil, for our present- 
day commerce is dependent very largely upon an adequate 
supply of oil. 
In the United States alone the production of crude oil has 
increased about 140 per cent since 1909, and that of gasoline 
about 800 per cent; but the number of automobiles registered 
has risen 2,570 per cent. The consequent enormous demand for 
gasoline has been met, partly by increasing the boiling-point 
range, partly by extracting liquid hydrocarbons from natural 
gas, partly by cracking, and partly from stored reserves. Ac- 
cording to the United States Geological Survey ° the unmined 
supply of petroleum is, roughly, 6,000,000,000 barrels which, if 
the present rate of production is maintained, will be exhausted | 
in about thirteen years. But the present rates of production 
and of consumption will undoubtedly be increased, thus bringing 
even closer the exhaustion of our oil supply. Therefore, the 
finding of a substitute for gasoline is of utmost, vital, and 
immediate importance. We must find some less-evanescent fuel, 
one that is inexhaustible or almost so. There is known at 
present only one; namely, alcohol. 
The pioneer experimental work on the production of an effi- 
cient alcohol engine has been completed.” It has been found © 
that in order to use alcohol efficiently, the following alterations 
in the present type of engine are necessary: 
Increased compression.—Alcohol is more efficient in engines 
of low piston speed and long stroke. This is due to the slower 
flame propagation of alcohol vapor in comparison with gasoline 
vapor and its ability to stand higher compression (180 pounds 
per square inch) without preignition. 
Preheating of air and alcohol vapor.—Alcohol will not vapor- 
ize at ordinary temperatures. The preheating necessary can 
be readily done by utilizing the exhaust, with an electrical con- 
trivance for starting from the cold. 
* Mineral Resources of the United States, pt. 1 (1917). 
"See Lucke, C. E., and Woodward, S. M., Tests on internal combustion 
‘engines on motor fuels, Bull. U. S. Dept. Agr., Off. Exp. Sta. 191 (1907). 
Strong, R. M., Commercial deductions from comparison of gasoline and 
alcohol tests on internal combustion engines, Bull. U. S. Geol. Surv. 393 
(1909). 
+ 
