454 



Oil Engines, 



larger part of the bottle is filled with asbestos. Surrounding 

 this ignition tube are two tubes or concentric walls forming. two 

 annular chambers c and d. The air required by the engine and 

 drawn into the cylinder on the suction stroke of the piston, 

 enters the outer chamber d, where it is warmed. It then passes 

 through holes d 1 in the upper part of the inner tube wall, and 



Fig. 17.— The Blackstone Oil Engine.— Diagram End View. 



thence into the annular space surrounding the igniter. At the 

 same time the charge of oil required for the next working stroke 

 is sent by the pump into the nipple e, just above the top of the 

 hot igniter. The oil is thus met by and carried and broken up 

 into spray by the warmed and thirsty air, and then completely 

 vapourised in its further passage down by the igniter exterior 

 to the passage f, the vapour valve g, and thence into the 

 cylinder at //. 



