The Trials of Oil Engines at Cambridge. 709 
into a worm on the shaft is made to automatically introduce 
the three cams in succession. The exhaust valve cannot there- 
fore be left open after the first revolution has been made. 
The workmanship and general arrangement of this engine 
are of a good and substantial character. 
Campbell Gas Engine Co., Ltd., Halifax. — In the “Camp- 
bell ” engine, which is of 6 nominal horse-power and costs 145Z. 
complete, there are no oil-pumps, the feed being by gravity 
to both engine and lamp. In this respect it resembles the 
“ Premier.” The air inlet is automatic, and there are only 
two valves — the inlet and exhaust. The governor acts upon 
the latter, keeping it open when the speed is too great, and so 
$ 
Fig. 9.— Section through vaporiser and valves of Fielding & Platt’s Oil Engine. 
a. Ignition-tube. b. Vaporiser tube. e. Air heating tube. 
preventing the suction of the piston from opening the air valve. 
The air and oil meet each other at right angles, and are thus 
sprayed into the vaporiser, which is heated together with the 
ignition tube by an external lamp. There are few working 
parts, and little to get out of order. The workmanship is good, 
though the oil-tank arrangements of the trial engine were 
primitive and would form a source of danger. 
Messrs. Fielding & Platt, Gloucester. — The engine of 8 brake 
horse-power exhibited by Messrs. Fielding & Platt costs 150L 
complete. It has a tubular vaporiser connected with the igni- 
tion tube by a small valve. 
Air is drawn through the heating tube c (fig. 9), and 
