This stud has a certain length of play, by means of a long hole or groove in the bar, so that when the springing lever is pressed up, the stud slides in the groove without giving motion to p. When the other springing lever is disengaged, it draws the opposite end of the handle, and causes p to draw the long hole at q up to its bearing against the stud, ready for the letting off of that first-mentioned springing lever. When this last mentioned lever comes to be disengaged, it suddenly draws p back, and turns the cock one quarter turn, and performs the like office of placing the horizontal rod of the other extremity of the handle ready for action by its own springing-lever. These alternations perform the opening and shutting of the cock, and to one of the springing levers is fixed a small force-pump w, which draws hot water from the case by the quick back-stroke, and forces it into the boiler by the stronger and more gradual pressure of a lever on the crank axis. It is also to be noticed that in certain cases we make the external periphery of the wheels w uneven, by projecting heads of nails or bolts, or cross grooves, or fittings to railroads, when required; and that in cases of hard pull we cause a lever, bolt, or claw, to project through the rim of one or both of the said wheels, so as to take hold of the ground; but that in general the ordinary structure or figure of the external surface of these wheels will be found to answer the intended purpose.
And, moreover, we do observe and declare, that the power of the engine, with regard to its convenient application to the carriage, may be varied, by changing the relative velocity of rotation of the wheels w compared with that of the axis s, by shifting the gears or toothed wheels for others of different sizes, properly adapted to each other in various ways, which will readily be adopted by any person of competent skill in machinery. The body of the carriage m may be made of any convenient size or figure, according to its intended uses. And, lastly, we do occasionally use bellows to excite the fire, and the said bellows are worked by the piston-rod or crank, and may be fixed in any situation or part of the several engines herein described, as may be found most convenient."
A carriage was built soon after the grant according to the construction above given, and exercised before the public for a considerable time in the neighbourhood of the present site of Euston Square, London. Succeeding patentees, it will be observed, have availed themselves of the judicious arrangement of these ingenious projectors.
Such was the indifference of the public to inventions of the kind, that nineteen years elapsed before another steam carriage for the common road was brought out, which was the subject of a patent granted to Mr. Julius Griffith in 1821; and this carriage, we are informed, was chiefly designed by foreigners.
At a is the furnace, supplied with fuel from a receptacle b. At c are two handles, one to open the feeding door, and the other to operate upon a damper. The boiler is at d in a double case packed with non-conducting materials. The boiler consists of tiers of horizontal tubes. Connected by bolts and straps to the frame of the carriage, is a reservoir of water e, which is drawn out by a force-pump atf, and by the return stroke injected into a pipe g at the bottom of the boiler, whence it is distributed into the lowermost range of tubes, and from these to the next above, the uppermost row being employed as steam reservoirs, and receiving the waste heat as it passes to the chimney, so as to increase the elastic force of the vapour before it proceeds along the steam pipe h to the engines, whence, after having given motion to the pistons, it is conducted by a pipe into the condenser i, which consists of a number of flattened thin metal tubes, exposed to the cooling influence of the air. The power of the engines is communicated from the piston rods to the running wheels of the carriage through the means of sweep-rods, (one of which is brought into view atj,) the lower ends of which are provided with driving pinions and detents, which operate upon toothed gear fixed to the hind carriage wheel axle.
The object of this mechanism, (which is of foreign invention, and denominated an Artzberger,) is to keep the driving pinions always in gear with the toothed wheels, however the engine and other machinery may vibrate, or the wheels be jolted upon uneven ground. In order that the engines and steam apparatus may not suffer from the concussions of the latter, they are suspended by slings at k to a strong iron framing 11, and to give the suspending chains some degree of elasticity, stout helical springs are introduced between them, as shown at m.
Griffith's Steam Carriage
The guiding of the carriage is effected by means of levers which turn round the axles of the fore wheels, so as to present the latter in the line of direction required. The axles are supported in a vertical frame, which is made to turn horizontally, by means of a guide wheel, on the top of a spindle, the lower extremity of which carries a pinion that takes into an internal toothed wheel at p.
We are not aware that Mr. Griffith's carriage ever made any public demonstrations of its working powers; but Mr. A. Gordon states that the chief difficulty which Mr. Griffith had to contend with, was the liability of having all the water blown out of the tubes, by the pressure of the steam on the lower part; no provision having been made for allowing the water to return, or for maintaining an equilibrium of pressure. Notwithstanding the failure of this attempt, it was rapidly succeeded by many other projectors in this line. The next in order of date was patented by Messrs. Burstall and Hill in 1824. Annexed is a cut representing an elevation of the machine, the fore part of the carriage being omitted as not being necessary to the explanation, and as effecting a saving of space.