The accompanying figure represents in section an engine of this class, a is the cylinder; b the slide-case; c the steam-pipe; d the slide, of the sort commonly known as the long side, which is hollow, and forms the eduction passage; f the way-shaft, by which the valve is worked; g is the condenser, cast in one with the bed-plate, and forming a pedestal to the cylinder; A the injection-pipe; k the foot-valve; l the air-pump, inserted in a chamber formed in the bed-plate; m the blow-through valve; n the delivery valve; o the hot-well; p the waste-water passage. The feed-pumps may be supposed to be arranged as in the engine first described, q and r being the passages connected with the pump; t is the beam gudgeon; v the beam; w the connectingrod: x the crank; y the side-frame, firmly secured to the bed-plate, and to strong flanges cast on the cylinder; z the guides in which the cross-head moves.
This arrangement appears to us to be inferior to the preceding one, and to possess few recommendations. Very little space is gained, or weight saved; and as no longer cylinder can be employed than with a Beam Engine, the crank of course must be shorter. In the Beam Engine, likewise, the parts acting on each half of the beam nearly counterbalance each other; but in the Lever Engine the weight of the steam and air-pump pistons, side-rods, and connecting-rod, acts all on one side of the fulcrum, and therefore requires to be counterbalanced, which is sometimes done by having one of the paddles of the wheel formed of cast iron, of the requisite thickness. Lever Engines are very common in boats on the Humber.