738 
The Trials of Oil Engines at Cambridge. 
3 ins., and its extreme length 12 ft. 9 ins. The running of the 
engine was not altogether satisfactory. The explosions were 
irregular and at times extremely violent, especially on the half- 
power consumption trial. This was probably owing to prevent- 
able causes, and was greatly relieved by a temporary slow down. 
The consumption was less than that of the “ Hornsby ” 
engine — namely, 098 lb. per brake horse-power hour on the 
three days’ run, and 090 lb. on the 2 hours’ full-power trial. 
There was no explosion-counter fitted, but no missed explo- 
sions were observed, and they have been taken, as equal to half 
the number of revolutions. The consumption on the 2 hours’ 
full-power trial was 0 62 lb. per indicated horse-power hour. 
The mechanical efficiency was 69 per cent. In its present con- 
dition the Judges felt that the engine did not merit the distinc- 
tion which would be given to it by the award of the second 
prize. 
The “ Campbell,” 10^- brake horse-power engine, can scarcely 
be called a portable engine. It is an excellent fixed engine upon 
a platform, but the only fact which could recommend its mount- 
ing is its clearance below, which is certainly a good point. The 
platform itself is a roughly-constructed tank filled with 165 
gallons of water, with no provision for cooling except conduction 
and radiation through the sides, and on the trial the water 
rapidly got hot and had to be renewed. On the three days’ 
trial, 1188 gallons of water were required for the 22\ hours’ 
run, which contrasts unfavourably with the 80 gallons of the 
“ Hornsby ” and 120 gallons of the “ Crossley ” engine on the 
same trial. The engine itself ran well except on the third day, 
when there was a large number of exhaust explosions. Its con- 
sumption was the lowest of any of the portables on the three 
days’ run, namely, 094 lb. per brake horse-power hour, and on 
the full-power trial it was second with 0’99 lb. per brake horse- 
power hour. The belt lead was not good and could only prove 
satisfactory over a very limited range. 
The Clarke-Chapman portable engine of 12 brake horse-power 
as exhibited was crude and unwieldy in design, though mani- 
festly capable of improvement. It was scarcely in running trim 
till close upon the finish of the trials, and was evidently in no 
condition to do itself or its makers justice. 
The leading particulars of these engines and a brief summai’y 
of the results of the trials are given in the tables on the two 
preceding pages. 
King’s College, London, W.C. 
D. S. Capper. 
