532 Miscellaneous Imjolements Exhibited at Warwick. 
engine for a given power is smaller than an engine having one 
ignition for every two and three revolutions of the crank. It is 
also claimed that the engine is more regular in its working, and 
this should be the case, provided that sufficient flywheel weight 
is supplied to allow of fairly uniform running on light loads, 
when firing would not take place at every revolution. 
The design of the engine is extremely simple, the main 
departure from those of the Otto type being the horizontal 
pump placed alongside the cylinder, by which means the charge 
of air and gas is pumped into the cylinder at a pressure of 
about 10 lb. to the square inch. Just at the point at which this 
pressure is attained in the pump, the exhaust poi-t in the engine 
would be open. The compressed mixture is, therefore, free to 
pass into the cylinder, through a self-acting non-return valve in 
the communicating passage, driving before it the remaining 
products of combustion in the cylinder. On the return stroke 
of the main piston compression takes place, and just at the 
turn of the stroke it is fired by the ignition tube. 
The strength of the explosive mixture may be varied, 
according to the work required of the engine, by a regulating 
cock on the inlet, sudden variations being controlled by the 
governor. 
Messrs. T. B. Barker J; Co., Birmingham (Stand 259). These 
engines are again of the Otto type, the gas, air, and exhaust 
valves being worked in the ordinary way by cams bn the side 
shaft. There were no special featui-es in these engines except 
that on the larger engine exhibited a starting arrangement was 
provided, in principle similar to that, already described on the 
Stockport engines, of introducing a charge of live gas into the 
cylinder at the ordinary gas pressure and firing the same, which 
is found to answer if the engine is running light. 
The Trent Gas Engine Company, New Basford, Nottingham 
(Stand 260). The engine exhibited by the Trent Company is, 
in its design, a distinct departure from all others, though, like 
the Campbell engine, it receives, when fully loaded, an igni- 
tion at every stroke. 
The engine consists of one long cylinder of two diameters, in 
which works a double-headed trunk piston, the forward cylinder 
constituting a pump, while the smaller or back one is the driving 
cylinder. In working, on the outward stroke gas and air are 
drawn into the annular space formed between the larger cylinder 
and the smaller piston ; on the return stroke the mixture is 
driven out and compressed into the explosion chamber, and is 
then ignited, the force of explosion actuating the smaller piston. 
The gas supply valve is operated upon and regulated by a 
