are fixed the carriages, D, on which the centres of the beam turn; these carriages being attached to the frame by screws, and not cast in one piece with the frame, permit the beam to be adjusted with the greatest accuracy to the rod of the piston. The shaft of the fly-wheel rests upon one carriage, screwed upon one side of the cistern, and upon another carriage, fixed at a convenient distance from the engine. The crank is attached to the end of the shaft, projecting over the cistern; E, the parallel motion; F, the rod which works the air-pump; G, the rod of the hot-water pump; the hot water is drawn from the top of the air-pump, which is enlarged, like the head of a common household pump; H, the rod of the coldwater pump; 1, the excentric motion from the shaft of the fly-wheel, which is attached to the tail-piece of the sway-bar, K; as the sway-bar librates, it alternately lifts two short arms, projecting in opposite directions from the sway-bar; one of these is marked L. The rods, M, which lift the valves, are made at their lower ends somewhat like the human foot, the heel resting upon the sway-bar, and the toe standing over the arms L. N, the governor, which is driven by a band from the pulley, o, on the shaft of the flywheel; the governor acts upon the valve, P, by means of the large bell-crank, q, and the rod, R. s, the usual syphon steam-gauge; T, the feed-pipe, with the apparatus for regulating the damper in the flue; u, the wire attached to the float in the boiler, and to the lever v, which raises the valve for supplying the boiler. The safety-valves are not shown; they are generally placed at the further end of the boiler.

The cistern of the engine is sometimes covered over with cast-iron plate to give it a neat appearance, and to allow the engine-man to stand securely while oiling the joints, &c. An engine on this construction works very steady, and with very little noise, and may be considered an excellent model to follow.

FENTON, MURRAY, AND WCOD'S ENGINE.

THERE is considerable variety in the arrangement of small engines. Fig. 51 is a representation of the engine of Messrs. Fenton, Murray, and Wood, of Leeds, who have manufactured a great number on this construction. Our cut is taken, with some slight variations, from an excellent plate in Smith's "Panorama of Art," a very useful compendium of information; and this was the first good representation that was published of a modern engine. In this construction, as in the former, the strain of the work is within the frame of the engine; the cylinder, the fly-wheel carriage, and the beam carriage all resting on a strong cast-iron plate, A, which forms a sort of floor, and is bolted down upon brick-work. The' cold-water pump в, the air-pump c, and the condenser D, are all concealed below the floor, a part of which is movable, in order to "get at" them easily. In the cut they are represented as placed in a wooden cistern, detached from the frame of the engine; but they are more generally placed in a cast-iron cistern, which is bolted to the cast-iron floor: E is the small cistern, containing the blowing valve, for blowing

off the steam when the engine is first set to work. This is not a necessary appendage to an engine, as the steam may be blown through the air-pump. The engine is furnished with a slide-valve, contained in the box F, which is worked by a rod attached to the bell-crank G, which receives its motion from the excentric by means of the lever H. The hot-water pump and the governor are omitted in the engraving.

DRYDEN'S ENGINE.

FIG. 52 is a representation of a small engine as constructed by Mr. Dryden; it occupies but little room; the strain is entirely within itself, and every part is easily got at. In this plan the great beam is done away, and a parallel motion of enlarged dimensions supplies its place. The piston-rod is attached to a T-piece, from the ends of which depend the crank-rods. There is a weight on the fly-wheel to balance the connecting-rods, &c. The valves and sway-bar for moving them are the same as in fig. 50; but instead of the usual excentric motion, the rod which moves the sway-bar is attached to a cranked part of the fly-wheel shaft, the peculiar form of which will be best understood by fig. 4, page 214. Two small hand-levers are attached by joints to the steam-pipes, and when the engine is started, can be readily moved under two pins projecting from the rods, which lift the valves. Directly below these is the handle of the injection cock, and close on the side is the fly-wheel; the engine-man has, therefore,