An auxiliary piston reciprocates in the other cylinder and is driven in timed relation to {TAIL ~ the working piston} by {HEAD ~ means} of a cam affixed to the crankshaft and a cam follower attached to a connecting rod 
An auxiliary piston reciprocates in the other cylinder and is driven in timed relation to { TAIL ~ the working piston } by { HEAD ~ means } of a cam affixed to the crankshaft and a cam follower attached to a connecting rod
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH