i 7 , 4 Carsten: Utilization of Waste Molasses 397 
The gasoline consumed by an ordinary, light tractor is about 
8 gallons per hectare for plowing. For the yearly crop on Ne- 
gros Island, the plowing would take 322,800 gallons of gasoline 
which at 10 pesos per case, amounts to 322,800 pesos. 
In estimating the quantity of alcohol that an engine equipped 
for alcohol consumption would require to plow 40,350 hectares 
of land, it is said that: 2 
Although the heat value of alcohol per pound is comparatively small 
(11.178 B. T. U. per pound), yet on account of the heaviness as a vapour, 
and the small volume of air required to burn it compared with benzine and 
gasoline, it yields 89.2 B. T. U. per cubic foot of mixture at 60° F. and 
atmospheric pressure. Moreover, the products of combustion are six and 
one half times greater than the volume of the unburnt mixture, with corre- 
sponding increase in the pressure developed. There is thus, thermally 
considered, not very much to choose between alcohol and gasoline; alcohol 
is, in fact, an excellent fuel for suitably designed internal-combustion 
engines, and is largely used in Germany where its production is encouraged 
by the Government; in 1904 the price of alcohol in Germany was only 30 
cents per gallon when purchased in large bulk. 
Alcohol engines require larger carburettors, piping, and valves than 
are necessary when gasoline is used. As the latent heat of alcohol much 
exceeds that of petrol, especially when water is present in any consid- 
erable proportion, it is also necessary to jacket the carburettor with hot 
water or exhaust gas and to heat the ingoing air to about 350° F. in order 
to ensure complete vaporization. The cylinder jacket water should also 
be kept at nearly 212° F.; too cool a cylinder results in imperfect combus- 
tion of the mixture, because of the formation of acetic acid, aldehyde, etc., 
instead of carbon dioxide and water only, causing loss of efficiency and the 
corrosion of internal parts. Starting up from cold is a special difficulty 
with alcohol, and engines are usually started with gasoline, the alcohol 
being turned on when everything is well warmed up. 
Some engines are arranged so as to start and stop on gasoline; in this 
way any traces of water or acid from the alcohol are cleared out of the 
cylinders and passages, during the last few revolutions of the engine, and 
corrosion of parts is thus avoided. 
Test on a 14 H. P. “Locomobile” alcohol engine of 8.28" bore and 11.8" 
stroke made by Prof. E. Meyer in 1901, showed a brake thermal efficiency 
of 24 per cent, using alcohol containing about 13 per cent water. The 
volume ratio of compression was 5.9. The cylinder jacket water temper- 
ature was maintained at 208° F. The engine ran at 280 revolutions per 
minute and developed 13.9 C. H. P. [B. H. P. ?] at full load. 
In round numbers, it takes 1.85 pounds of alcohol as against 
1 pound of gasoline. Assuming the gasoline specific gravity to 
be 0.72, 1 pound of gasoline would equal 0.167 gallons; and 1.85 
pounds of alcohol with a specific gravity of 0.8228 would equal 
0.268 gallon. Therefore, 322,800 gallons of gasoline will de- 
velop the same number of British thermal units as 517,771 
2 From the Engineer’s Year Book for 1916. 
