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Engineers and Mechanics Encyclopedia 1839: Railways: William Francis Snowden

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Im1839Enc-p462.jpg

The next invention in the order of time that presents itself to our notice, is one possessing considerable originality; and though it has not been carried into effect, it contains some ingenious and amusing suggestions, that have formed the groundwork of subsequent inventions.

It is the subject of a patent granted to William Francis Snowden, of Oxford-street, London, on the 18th of December 1824, for a "new invented wheel way and its carriages for the conveyance of passengers, merchandise, and other things, along roads, rails, and other ways, either on a level or inclined plane."

The specification describes the invention under two distinct beads; the first, respects the wheel-way, explains it as consisting of a hollow trunk with a platform of iron on the top for waggons or other carriages to roll upon; inside the trunk is placed a machine, called by the patentee a mechanical horse, to which is connected a toothed wheel, that is made to revolve in a horizontal plane, and to take into the teeth of a horizontal straight rack fixed on one side of the hollow trunk.

The vertical axis of the horizontal toothed wheel passes through a longitudinal opening in the wheel-way; above which it is connected to a locomotive steam-engine, and is actuated thereby; through the medium of bevel geer the motion thus communicated to the latter by the engines, is applied by the vertical axis to the horizontal wheel of the mechanical horse, inside the hollow trunk; and as the horizontal wheel is geered into the toothed rack, which is fired on one side of the trunk, the mechanical horse of necessity moves forward with the same velocity as the horizontal wheel is made to revolve by the power of the engine.

Those to whom our literal description may not be clear, will understand it by the annexed figure, which affords a longitudinal section of the mechanical horse, and the hollow trunk or wheel-way. a is a vibrating cylinder, and b the boiler of a locomotive engine, by which the bevel geer c-d is actuated, and through the medium of the vertical axis e, the horizontal toothed wheel which takes into a toothed rack g; the mechanical horse h is made to advance in its course, and to take with it the engine and the train of waggons that may be in connexion. w-w is the wheel-way, and it the hollow trunk.

As the top of the wheel-way is supposed to be flat, and the carriages without lateral flanges to their tires, it is proposed to guide the carriages by means of tongues like that at i, which enters the longitudinal aperture, and which may be provided with an antifriction roller to prevent lateral rubbing. The inventor proposes to adopt a similar arrangement to the foregoing for the towing of barges, by erecting his patent wheel-ways by the sides or banks of canals and rivers.

The second head of invention under the patent is of a more singular character, and however preposterous it may at first appear to those who have not considered the subject, it is in reality by no means absurd in principle, nor in the rationale of the proposition; but we will first describe it, and afterwards make our observations.

Instead of placing horses outside of a carriage to give it motion, the patentee puts them inside for that purpose; and his reason for doing this, that of increasing the force or velocity, will to many appear to be quite as paradoxical.

Im1839Enc-p463a.jpg
Im1839Enc-p463b.jpg

Fig. 1 affords a perspective view of a machine of the kind, and Fig. 2 a section of the wheel-way and mechanism by which the process of propulsion is effected.

This second part of the patent is thus described in the Register of Arts:-

"b-b represents a vertical section of the road in which an excavation is made, and the ground well rammed, so as to lay down, at uniform distances, a series of cut-iron frames or sleepers c-c. In the several partitions of the sleepers are placed, lengthways, four lines of timber. The two principal rails, d-d, are of oak, and stand about three inches above the level of the other parts. The other two lines of timber, e-e, are three-inch planks, set on edge, and bolted to the framing.

“Resting upon these deal planks and the iron partitions, and flush with the oak timber, are laid, crossways of the road, short pieces of three-inch oak plank, leaving an open crevice about one inch and a half wide between them. These short planks are laid edge to edge, uniformly along the whole line, so as to form a level floor, over which is screwed down a complete covering of wrought-iron plates, a-a.

“On this hard and level surface, the wheels of the carriage are intended to roll. Inside the hollow trunk is the mechanical horse, which is actuated by motive force implied above, through the medium of similar gear to the before-described. Only two-toothed wheels are shown in the trunk; there is, however, another, which cannot be seen in this view, which, when put into gear with the opposite rack, reverses the rotatory motion, and causes the carriage to proceed in the same direction. The lowest wheel of the three shown is made light, as it only operates as an antifriction roller, and for that reason occupies the whole space between the two three-inch deals.

“The perspective sketch in Fig. 1, though rather disproportioned in some of its parts, exhibits a carriage of the kind described in the specification. It consists of two stories, - the upper one for passengers, containing both inside and outside berths; and the lower one for merchandise, which is deposited on a circular floor, around which two horses are made to work, as its a mill, being yoked to the two opposite extremities of a horizontal lever, that turns a vertical axis, to which is connected multiplying gear that causes the mechanical horse in the hollow trough, and the carriage above, to move at any predetermined velocity of motion; the horses, however, continuing to move at that slow pace (of about 2.5 miles per hour), by which they can most efficiently exert their force. The diagram marked Fig. 2 is explanatory of these motions: g-g are two yokes, to which the horses, being attached, give motion to the horizontal lever and the vertical shaft h, on which is also fixed, close under the floor of the carriage, a large horizontal spur-wheel i; the revolution of this wheel actuates a pinion j, which pillion being on the same spindle as the toothed wheel on the mechanical horse, which takes into the rack, causes the carriage to advance at about four times the velocity of the horses, or at ten miles an hour.

“Mr. Snowden calculates the power of an average horse, in drawing a load, at the rate of 2.5 miles per hour, for four hours a day, as equal to the constant force of a weight of 250 pounds, when drawing in a straight line if the speed of the horse be doubled or increased to 5 miles per hour, his power of traction will be reduced to only 50 pounds; and if the speed be again doubled, or made 10 miles per hour, the horse can do no work whatever, except through only a very short space of time. The slow motion, therefore, is by far the most favourable mode of applying the power of a horse; and although the contracted circuit of a mill-walk is unfavourable to the full exertion of his powers, Mr. Snowden estimates that a force of about 200 pounds may thus be obtained.

“Of this available force he proposes to sacrifice three fourths, by means of multiplying gear, into velocity; and thus enable each horse to give out, in effect, a force of 50 pounds at 10 miles per hour; whereas, if the horses were to move themselves at that velocity, they would be totally ineffective.

“If, therefore, we consider two horses to bestow a force of 100 pounds, and that the resistance on the patentee's wheel-way is no more than that of the Manchester and Liverpool railway, namely, 1 in 290, we have 100 x 240 = 24,000 lbs. propelled by two horses, at the rate of 10 miles an hour. But the friction of such machinery must be considerably more than 1 in 240, and the above-estimated force of a horse moving in a circle of 16 feet diameter, is probably much too high.

“Let us therefore suppose the useful effect to be only half, reducing it to 12,000 lbs. The popular objection to this plan, is the apparent absurdity of the horse having to carry his own weight; but this objection equally applies to the steam engine, or any other locomotive power: the whole question, however, resolves itself into one of convenience and economy, as applied to particular cases and circumstances, which We cannot here discuss; and as we shall have occasion, in our account of Brandreth's Cyclopede, to notice the subject again, we shall here conclude with the remark, that we believe it is worthy of the consideration of the machinist to devise the most perfect locomotive machinery, for converting the force of a horse at a slow motion, into a higher velocity with a diminished force.

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