Engineers and Mechanics Encyclopedia 1839: Railways: David Napier
The specification 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 communicates the power 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; l 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 forming one entire piece, is suspended by springs n-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 communicate 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.