Messrs. Pullan and Lake have recently patented some improvements of a very practical and extensive character in traction-engines and road locomotives, which, indeed, appear to combine all the qualities desirable in a traction-engine. A side elevation and an end view of Messrs. Pullan and Lake's agricultural locomotive is shown at Plate XXVII. The cylinders are mounted on the top of the barrel of the boiler, as shown, the piston rod head being guided by means of a short tube, moving on a horizontal round bar. From these piston rods proceed connecting rods to a main shaft of the usual form, which is furnished with a fly-wheel, as the engine is intended to drive thrashing-machines and other agricultural machines. In the end elevation the crank-shaft and counter-shaft are omitted, their positions being indicated by the dotted lines. This engine is furnished with gearing arranged to give two speeds; the position of the gearing is shown in the drawing. Suitable clutches are furnished for working this gear. The driving-wheel is caused to rotate by means of a chain acting upon a toothed wheel, as shown. This chain is liable in the course of time to yield and become loose, wherefore it is necessary to have some means of increasing at will the distance between the counter-shaft and the axle of the driving-wheel, and such means, are supplied by the following arrangement. The axle of the driving-wheels is carried by an eccentric, which may be caused to revolve by means of a tangent screw placed beneath it, and by means of this eccentric the driving-chain can be tightened at will. The engine is furnished with a common governor, for use when it is acting as a stationary engine, and which may be disconnected when the engine is running. The reversing gear is similar to that of an ordinary locomotive, and the driving-wheels carry plates on their peripheries intended to give a better hold upon the road. These wheels may also be supplied with teeth, which may be withdrawn when necessary by means of a screw: thus we have the advantage of having movable teeth without the friction inherent to Bray's arrangement. Behind the driving-wheel and just above the eccentric, is shown in dotted lines the feed-pump, and about two feet farther, towards the hinder part of the engine, is shown an outside pump, in connection with which is a three-way cock, by means of which the pump can be used to fill the water-tank or the boiler, or to expel water through a jet, after the manner of a fire

engine. This engine is also sometimes furnished with the superheater above alluded to. The engine is steered by means of apparatus placed in front of the boiler, motion being imparted from a hand-wheel through suitable bevel wheels, and a pinion to the toothed segment upon the driving-axle of the leading wheels. When it would be more convenient to dispense with the steering apparatus, the latter can be removed by withdrawing it from the socke in which the bar supporting it is keyed; hence this machine may be used either as a common portable engine, drawn by horses, or as an agricultural locomotive engine.

In Pullan and Lake's traction-engine, patented at the same time as the locomotive above described, many advantages are combined. The engines are carried on a frame distinct from the boiler, and are protected from the weather by suitable covering; gearing is used for driving, in place of the chain described above, and a most beautiful and ingenious arrangement is adopted in the construction of the driving-wheels, which secures the gear against breakage. The wheels are also furnished with teeth, which may be caused to act or not by a simple adjusting contrivance, of which there are many varieties. The result of the form of this engine is such that it is quite safe in running over any ground; for, if the axis of the driving-wheels be canted in one direction and that of the leading wheels in the other, no dangerous results would ensue. Two or three of these engines have already been made, and have been found most efficient, some of them having been furnished with super heaters and some with contrivances to prevent the boiler from priming.

CHAPTER XXIII.

ON STEAM FIRE-ENGINES.

THE Constant increase in height and other dimensions of the buildings in our large towns, has long called for more efficient means of extinguishing conflagrations than those supplied by the ordinary hand-engines. This necessity appears lately to have been better understood than before, and consequently steam fire-engines are gradually coming into extensive use.

For many years the floating fire-engines were the only ones in the metropolis worked by steam, but some time since, one of Messrs. Shand and Mason's steam fire-engines was supplied to the London Fire Brigade. This engine has a short upright boiler and a horizontal cylinder, acting direct upon the pump. Upon the piston rod is forged a slotted link, and in the slot moves a crank. pin, being part of a crank attached to a shaft, and carrying a fly. wheel and the usual gear for working the slide-valve, &c. This engine is always kept ready for service, the water in the boiler and also the steam-cylinder being kept hot by gas burners, so that in a very few minutes steam can be raised to work the engine. This engine must be looked upon in the Mght of an experiment which has proved eminently successful, having done good service at many metropolitan fires under the superintendence of Mr. Gerrod, the engineer to the Brigade.

Messrs. Shand and Mason have made many improvements in the engines constructed subsequently to that above mentioned, and there seems to be but little doubt of steam fire-engines coming ex tensively into use.

A short time since Mr. Wellington Lee, of the firm of Lee and Larned of New York, imported an American steam fire-engine,

which was tried at Mr. Hodge's distillery, under Mr. Lee's superintendence. The boiler is constructed with a view to raising steam. rapidly, and in this it proved eminently successful.

An objection has been raised by some to horizontal pumps, on the ground that any grit in the water will settle upon and injure the lower part of the internal surface; but this has been contradicted, as some horizontal pumps which have been at work with foul water for some considerable time have remained uninjured. But it is certain that grit may be injurious under some circumstances, as was experimentally proved by Mr. Roberts, who caused a fire-engine to be worked with water containing a sediment, which was kept constantly stirred up while the experiment lasted, that is to say, for about twenty minutes, when it was found that the surface of the pump was much injured.

We have selected, as an example for illustration, a fire-engine of peculiar construction, manufactured by Messrs. Silsby, Mynderse, and Co., of New York. A side elevation is shown in Plate XXVIII.

It is furnished with an upright boiler of the multitubular description, containing three hundred one and a quarter inch tubes. In the lower part of the chimney is placed a fan or blower, which receives its motion from one of the hind wheels of the engine by means of a band, the object of which is to create a draught and raise the steam rapidly, while the engine is being drawn to the spot where its services are required. At the back part of the carriage and behind the boiler is fixed a rotary engine, constructed according to Holly's patent; which engine causes a shaft to rotate, the shaft passing nearly the entire length of the carriage and driving a pump constructed on the same principle as the engine, and fixed close behind the driver's seat in front of the chimney. Just below the boiler in front of the frame work, is fixed a rotary donkey engine and pump combined, similar in every respect to the main engine and pump, and intended to supply the boiler with water when the main engine is at work. An ordinary feed pump is geared by ordinary bevel wheels to the main shaft. The steampipe is seen proceeding from the top of the boiler in a curved form down to the rotary engine, and the exhaust pipe is seen passing from the boiler upwards to the funnel. The usual steam-whistle,

safety-valve, and other valves and gauges are applied to the boiler; the engine is supported by india-rubber springs. A heater is furnished to heat the feed water passing to the boiler. The weight of the engine is from two to two and a half tons, and it is said to be capable of throwing a one and a half inch stream of water to a distance of a hundred and seventy feet, when working at a pressure of about fifty pounds on the square inch.