File:Steeple engine.jpg

English: Steeple engine. The explanation accompanying the illustration is as follows: "At a is the condenser, constituting the base of the [engine] cylinder b. The cross-head c of the piston-rod, instead of being parallel to the shaft, as is usual, stands at right angles to it; and from the ends of the cross-head rise two rods d d, which are connected at top, forming with the cross-head a triangle. Through the apex of this triangle passes a pin, the ends of which work in guides e, to cause the piston-rod to preserve a parallel motion. The connecting-rod f is suspended from the central part of the pin, and the lower extremity is connected to the crank g, which revolves within the triangle." Note that in this type of engine, the connecting rod rotates neatly within the triangular crosshead assembly.