The of the patent granted on the 4th March 1831, to the Messrs. Napier, of London and Glasgow, shows, that those gentleman, notwithstanding their unquestionable ability as practical engineers, were but indifferently informed upon the progress of invention in locomotion. They describe their improvements to consist, " First, in communicating the power of the engine or engines for propelling the carriage to the wheels, by means of a belt, 'strap, or band, made of leather or any other suitable material, and which belt, or band, works upon two pulleys or drums, the one fixed upon a shaft connected with the engine or engines, the other fixed upon, or connected with, the axle or wheels of the carriage ; more than one of which belts may be used if necessary. This will be better understood by reference to the cut on the next page. a is a horizontal steam boiler, with an hemispherical end ; at b are the two cylinders of the engines working horizontally, and fastened upon the boilers ; c c is the framing of engines, which is also fastened to the boilers and engine cylinders • d connecting rod of engine ; e the crank shaft of engines, upon which is fixed the pulley or drum f, from which pulley the strap g com municates thepower of the engine to the pulley or drum h, which in the present case is fixed on the middle of the wheel axle i ; k k the hind wheels of carriage ; 1 fore wheel of carriage, which turns on a circular plate for the purpose of guiding the carriage on the common roads. The boilers and engines being firmly fastened together, thus foaling one entire piece, is suspended by springs n n from a frame work o o, resting upon the wheel axles of the carriage, and having no connexion with the said carriage or frame-work, but by springs, and belts or bands. It is thus freed from the severe jolts and shakes of the road, which are so injurious to machinery." The above arrangement is applicable to common or turnpike roads, and may be easily altered to be suitable for railways. The patentees lay no claim to this or any other arrangement of the parts of the machinery, but merely to the application of the belt, straps or band, made of leather, or any other suitable material, with either cylindrical or conical pulleys or drums, to com municate the power of the engine or engines to the wheels of carriages.
The specification likewise describes some varieties of a cylindrical boiler made with a longitudinal central flue, terminating in an hemispherical chamber or cap, covering the whole of the end of the boiler; from this chamber the heated gases are compelled to return through a series of smaller tubes to the front end of the boiler, whence they are conducted to the chimney.
We have already described, at page 477, a patented improvement by Mr. Robert Stephenson on the axletrees of railway carriages. At the period we are now treating of, another invention, from the same celebrated engineer, presents itself to our notice; it is dated the 11th of March 1831, and is entitled, "Improvement in the axles and parts which form the bearings at the centres of wheels, which are to travel upon edge railways." In order to produce rotation in the wheels, and consequently progression of locomotive carriages, it is necessary to fix the wheels on the ends of the axles, and when this fixture is effected in the usual manner, the weight of the car riage and its contents is supported by concave bearings resting on the upper surfaces of the cylindrical ends of the axles, and hence arises a difficulty in keeping the rubbing parts constantly lubricated, as the oil supplied to the parts in contact will have a tendency to escape by its gravity to a more open space on the lower sides of the axles ; and the consequence of this is, considerable waste of oil, with an imperfect lubrication.
To remedy this, Mr. Stephenson employs for each pair of wheels, a double axle, consisting of a hollow casing, on the extremities of which the wheels are firmly fixed, and a solid axis passing through the hollow casing, and supporting on its ends the weight of the carriage, through the medium of hollow bearings attached to springs of the usual construction, which connects the bearings with the side rails of the carriage, placed necessarily on the outside of the wheels. Thus the supporters or wheels being fixed to the concave parts of the bearings, and the supported weight or carriage being connected with the convex or solid part of the bearings, the ell will have a tendency by its gravity to accumulate on the rubbing parts, and thus combine a perfect lubrication with an economical supply of lubricating material.
The solid axles are made thickest near their extremities, so that the parts which pass through those portions of the hollow axles which are fixed into the naves of the wheels, and at the same time the apertures of the corresponding parts of the hollow axles, are diminished, both being turned perfectly cylindrical, that they may be fitted together with facility, and come into contact only where the bearings are intended to take place.
In September 1831, Mr. G. H. Palmer, of Manchester-street, Grays Inn Road, took out a patent for a variety of improvements appertaining to locomotion, which we shall proceed to notice.
The abstract parts of the engine and boiler which he claims as being novel either in principle, or as regards their peculiar modification, are,— First, The self-regulating blast apparatus, by which the quantity of fuel to be ignited in a given time is governed, m order to insure the generation of a volume of steam, suited precisely to all the variable speeds and powers of the engine.
Secondly, The steam calorific self-adjusting apparatus, which acts in conjunc tion with the blast regulator, and is so contrived as to lift the weight from the lever of the safety valve, and permit the steam to escape from the boiler should the aforesaid apparatus fail of instantly checking its evolution.
Thirdly, The self-acting safety apparatus, by which the of the boiler is insured, should the apparatus for supplying it with water fail in its effect, so that in the event of the water in the boiler being reduced below a determined level, the process of combustion will be instantly suspended, and the boiler pro tected from injury.
Fourthly, Making the products of combustion evolved from the furnace escape into the atmosphere below the level of the furnace bars, which will most effectually prevent the admission of atmospheric air into the furnace, excepting that portion which the blast and calorific regulating apparatus permits the blowers to project upon the fuel undergoing combustion.