Miscellaneous Implements Exhibited at Doncasier. 535 
3 horse-power nominal, but it was explained that in future this 
size of engine should be registered at 2^ nominal horse-power. 
The movements of the engine are as follows : On the 
crank shaft, just outside the main bearing, is a pinion which 
gears into a second one running at one half the number of 
revolutions. On the second pinion is a cam-plate which at 
every alternate revolution of the engine actuates a bell-crank 
lever, one end of which is held up to the cam face by a spiral 
spring ; the other end of the lever works a small feed-pump, 
the suction-valve of which is controlled by the governor, which 
in rising " trips " it to a gi-eater or less extent. A further 
adjustment of the stroke of the pump is effected by a regulating 
screw-stop acting on the bell-crank lever iu opposition to the 
spiral spring which brings the lever in contact with the cam 
face. 
This feed-pump takes its supply of oil from an oil chamber 
in the bed-plate underneath the crank shaft, and delivers it into 
a combustion box placed immediately behind the cylinder, 
and it is this combustion box which is the special feature of the 
engine. It consists merely of a cast-iron box communicating 
directly with the back end of the cylinder. At starting, this 
box is heated by means of an oil lamp and hand blast to the 
requisite temperature for ignition of the oil, and when this is 
done, the engine is turned round by hand for one or two revo- 
lutions, and the heat generated by the recurring explosions 
maintains the temperature for the continued ignition of the 
charges of oil pumped into it. The air is admitted through 
the ordinary inlet valve, and the exhaust valve is actuated by 
a vibrating lever, passing along underneath the bed-plate, and 
worked by a cam on the intermediate shaft carrying the 
second pinion already referred to. 
A trial of the engine was made, with a heavy mineral oil 
of a specific gi'avity of 0'85, and with a reported flashing point 
of 150° (the oil was tested previous to trial up to 135° without 
flashing), with the following results : — 
The mean brake horse-power = 2-9. 
Total oil consumed in 2 hours = 10 lb. Of oz. 
Oil per brake horse-power per hour = 1-o-i lb., or 1-45 pints per 
brake horse-power per hour. 
The cost of the oil was stated to be od. per gallon. Although 
the consumption of oil per brake horse-power is in excess of 
the result obtained in previous competitive trials at Plymouth, 
it must be borne in mind that the engine now under considera- 
tion was of much smaller power, and consequently so high an 
eflSciency would not be obtainable as in the prize engine on that 
