The Trials of Light Portable Motors at Plymouth. 599 
Russian lustre oil, costing, it was stated 6d., per gallon. Nor- 
mally, there is one explosion to every three revolutions. The 
charge is fired by a platinum coil kept incandescent by the flame 
of a lamp, the moment of ignition being determined by the 
movement of a slide valve. The engine is regulated by a hit-or- 
miss governor, which suppresses the admission of vapour if the 
speed rises. The lamp for heating the vaporising chamber was 
Pries 
tman 
Triple (if Ptbnlniiw nil T-*yi cinp-a 
Full-power 
Half-power 
Brown & May 
trial 
trial 
. — , 
BTake. 
3 504 
3 50t 
3 16 
79 
39-25 
11-5 
Mean spring balance reading, lb. . 
391 
007 
0-77 
Effective load on brake, lb. . . . 
7509 
3918 
10 73 
150 
120 
90 
Total revolutions in trial . . . 
26,932 
21,700 
30,615 
Mean speed, revolutions per min. 
1795 
1808 
340-2 
4-AQfi 
l uy i 
Indicator. 
Mean effective pressure, lb. per ) 
do yo 
OA./? C 
Z\j bo 
541 
Explosions per min. taken at . . 
89-75 
90-4 
83 
Indicated horse-power .... 
5-243 
3-210 
1-450 
0-857 
07385 
0-757 
Oil Fuel. 
13 97 
9-375 
503 
5-588 
4-687 
3-35 
Oil used per hour per indicated - ^ 
1066 
1-460 
2-31 
Oil used per hour per brake-horse- 
1-243 
1-984 
3054 
Jaclcet Water. 
3,251-6 
Jacket water per hour, lb. . . . 
1,301 
Mean initial temperature, Fahr. . 
6014° 
61-3° 
Mean final temperature, Fahr. 
103-69° 
93-98° 
Rise of temperature, Fahr. . . . 
43-55° 
50 58° 
32-68° 
lighted at three hours thirty-two minutes. But the engine did 
not really get started till four hours twenty minutes, the engine 
being kept going in the interval by hand regulation. The 
exhaust was very violent, partly from the high pressure at the 
end of the stroke, and partly also it appeared from the imper- 
fect combustion during the stroke. The explosions were also 
very irregular. The following observations were made on this 
point : — 
