Report on Miscellaneous Implements at Newcastle. 211 
terring the officers of the Society from pronouncing upon the 
merits of Spiel's engine, must be taken for what it is worth by 
individual buyers, who, if cautious, need have no fear of accident 
in using benzoline (see fig. 11). 
Spiel's petroleum engine is a German invention, only re- 
cently introduced into this country, where it is manufactured 
by the exhibitors. It depends for its action upon the explosion 
in the cylinder of a mixture of petroleum spray and air, just as 
Fig. 11. — SpieVs Petroleum Engine. 
a gas engine depends on the explosion of a mixture of coal gas 
and atmospheric air. 
At the first, or "induction " stroke, the piston draws in behind it a supply 
of air through a suitable valve, which opens at the right moment for tliis 
purpose. At the same time, a small but definite quantity of petroleum is 
measured out from a reservoir by means of a plunger working in a barrel like 
that of a pump. At the end of the first stroke the air valve closes, and the 
oil plunger is lifted, ready to furnish a second supply. The air and oil, thus 
measured, enter the cylinder together, the former in a fine spray, a con- 
dition assumed under the action of the oil plunger, which, driving it forcibly 
against certain obstacles, breaks it up into the finest particles. 
During the second, or " compression," stroke, the explosive mixture is 
compressed by the piston to about three atmospheres, and, at the end of this 
stroke, is exploded through a firing valve. The next is the " working 
stroke," at the end of which the exhaust opens, and the return of the 
V 2 
