536 Miscellaneous Implements ^Exhibited at WaTwich. 
of oil is regulated by tbe governor, a lever from wbich trips the 
roller sideways off the cam, and thus prevents the oil admission 
valve opening. The excess of oil pumped flows back through 
a return pipe to the suction tank. 
The oil with which the engine was working was a coarse oil, 
having a specific gravity of -850 to -860, with reported flashing 
Fig. 5. — Robey’s Unilertype Petroleum Engine. 
point of 240° Fahr., the price being 44. 15s. per ton oi 2C3 
gallons. 
Tlie. engine is described as of 5 effective horse-power, 
and, though no test was made of the consumption of oil, it 
may fairly be assumed that it might be sent out with its 
water and oil vessels fully charged, and that they would not 
require re-charging for a week. 
The undertype engine (Art. 4022) is an admirable arrange- 
