72 o 
The Trials of Oil Engines at Cambidge. 
A two hours’ full-power trial was followed by a two hours’ 
half-power trial and a four hours’ consumption trial running 
light. 
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Fig. 19. — Wells Brothers’ Fixed Engine— Mean Card two hours’ full power trial. 
Cylinder Volume in cubic feet. 
/ 5 7 * 
Fig. 20. — Weyman & Hitchcock’s “ Trusty” Engine — Mean Card two hours’ full power trial. 
Cylinder Volume in cubic feet. 
Indicator diagrams . — These were taken as nearly as possible 
every fifteen minutes on Crosby indicators. In * three cases, 
where Crosby’s were unsuitable, a Wayne indicator was tried. 
This gave very good and reliable cards and was found subse- 
