ment in the motor. An engine built by 
Korting Brothers of Hanover, fitted with 
a vaporizer invented by Petreano, tested 
at the Polytechnic School at Charlotten- 
burg by Professor Slaby showed a con- 
sumption of 550 grams of 86.2 per cent 
alcohol by weight, which is equivalent to 
1.21 pounds, or 1.4 pints, or a thermal 
efficiency of 17.5 per cent. This result 
showed an advance of nearly 50 per cent 
in thermal efficiency over the Grobb en- 
gine tested a year or so earlier by Pro- 
fessor Hartmann. Following this improve- 
ment there resulted a continual develop- 
ment of the alcohol motor, interest in 
which was kept up by exhibitions in 
which prizes were offered and by scien- 
tific societies. The most important of 
these are given below: 
Exhibition at Halle-on-Saal, 
June 13-18, 1901. 
Exhibition (national) at Paris, France, 
November 16-24, 1901. 
Exhibition at Berlin, Germany, Febru- 
ary 8-16, 1902. 
Exhibition (international) 
France, May 24-June 1. 1902. 
Exhibition at Madrid, Spain, late in the 
year 1902. 
ws at Montpellier, October 11-21, 
1902. 
we at Paris, France, March 11-17, 
1902. 
Exhibition (international) at Vienna, 
Austria, April 2-June 12, 1904. 
Exhibition at Rome, Italy, February 6- 
16, 1904. 
Besides the above named, there were 
many others of lesser importance, all con- 
tributing to the rapid development of 
this class of machine. 
The results of this development may 
be suramed up by saying that the thermal 
eficiency of the motor was raised to 
something over 30 per cent, which is 
quite a remarkable showing in compari- 
son with the original figure of 12.2 per 
cent in 1894.) It must be clearly under- 
stood, however, in interpreting these fig- 
ures that they are the best possible at- 
tainable at the time reported. They in- 
dicate, so far as the fuel costs are con- 
cerned, that with a motor specially con- 
structed for alcohol the fuel prices per 
gallon might be twice as much for alcohol 
as for petroleum distillate and still give 
power for less money, assuming that at- 
Germany, 
at Paris, 
42 ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 
tendance, repairs, lubrication, ete., cost 
no more in the case of the alcohol engine. 
The Office of Experiment Stations of 
this Department, in connection with its 
Irrigation and Drainage Investigations, 
has tested a number of different types of 
gasoline engines with alcohol, and ob- 
tained figures which show the compara- 
tive consumption of gasoline and alcohol 
in the same engine. The detailed results 
of these tests will be published in a tech- 
nical bulletin, but the general results 
may be given here. The first tests were 
made without any particular attempt at 
obtaining the best adjustment of the en- 
gine for each fuel, and showed a consump- 
tion of alcohol two to three times as 
great by weight per horsepower hour as 
was necessary with gasoline or kerosene. 
These figures indicate the necessity or de- 
sirability of determining the proper con- 
ditions of adjustment, because these were 
found to have a serious influence on the 
amount of fuel consumed. With care in 
adjusting the engine so as to secure the 
most economical use of the alcohol, it 
was found that, under like conditions, a 
small engine consumed 1.23 pounds of al- 
cohol to 0.69 pounds of gasoline per brake 
horsepower hour—that is to say, with the 
best adjustment of the engine for each 
fuel there was required 1.8 times as much 
alcoho] by weight as gasoline per brake 
horsepower hour. It was also shown in 
making this adjustment that it was pos- 
sible to burn more than twice as much 
alcohol as stated, by improper adjust- 
ments, and still have the engine working 
in an apparently satisfactory way. The 
range of excess gasoline which might be 
burned without interfering seriously with 
the working of the engine was not so 
great, being a little less than twice as 
much as the minimum. These early ex- 
periments, therefore, confirmed the early 
results secured in Germany, to-wit, that 
an engine built for gasoline or kerosene 
will, when unchanged, require about twice 
as much alcohol by weight for the same 
work; but they also indicate something 
that is not pointed out by the reports 
sent us from abroad—that is, the great 
importance of securing the best adjust- 
ment of the machine. 
