706 The Trials of Oil Engines at Cambridge. 
Oil is pumped through a “ sight feed tube ” to the top of the 
vaporiser. It was originally fed by gravity, but this arrange- 
ment was discontinued from fear of accidental fire. The 
oil, with a small proportion of air, passes round the annular 
passage, is gradually vaporised as it falls to the bottom, 
rises through a series of holes into the central chamber, and 
passes down through the vapour valve into the cylinder, where it 
meets the additional air- 
supply required. The 
pumps and valves are all 
driven from a lay shaft, 
shown in fig. 6. A side 
lever, with a trip gear 
between it and the lay 
shaft, works the vapour 
valve, and an inertia 
governor upon the trip 
prevents contact when 
the speed is too great. 
There are adjustments 
upon the oil, vapour, and 
air valves for adapting to 
different oils ; and the 
compression can be varied, 
as in the Hornsby engine, 
by packing pieces in the 
connecting - rod. The 
ignition tube is heated 
by an external lamp, 
across the flame of which 
a powerful blast of air 
is driven by an air-pump. 
The workmanship is good, 
but the design involves a 
considerable number of 
working parts, and the 
methods of adjustment are not quite as substantial as one would 
like for an engine which is to be placed in the hands of a farm- 
labourer. A pump to circulate the jacket water is provided, but 
was disconnected upon the trial, being replaced by gravity tanks. 
The second engine exhibited by this firm is of larger size 
(6 brake horse-power), and costs 149k It is of precisely similar 
design, but has a Defries lamp in place of the air blast. It was 
withdrawn from trial after the three days’ run. 
Britannia Co., Colchester. — The Britannia Co.’s engine is of 
Fig. G.— Arrangement of valves, levers, &c., in Weyman 
& Hitchcock's “Trusty ” Oil Engine. 
«. Side lever. 
c. Governor. 
d. 1 Rocking levers tvork- 
e. I ing oil and air valves. 
<j. Air inlet pipe. 
q. Oil reservoir for lamp, 
it. Oil supply pipe to lamp. 
s. Air blast pipe. 
T. Air-pump. 
u. Lamp reservoir, 
tv. Oil pump. 
x. „ discharge. 
Y. Oil supply pipe. 
v. . Pet cock.’ 
