tain these facts; and shall now proceed to describe the mode of action upon the Railroads, in the neighbourhood of Newcastle, where their use has been very extensive.

Fig. I. Plate III. represents a ground plan of the wheel W W of a self-acting plane, round the rim of which the rope winds, by which the loaded carriages drag the empty ones up the plane. The wheel is generally cast-iron, about six feet diameter, with six spokes, and a grooved rim for the rope to wind upon, the groove being only of sufficient width to hold the rope within it as the wheel moves round; consequently the rope, when in action, only passes round one half of the wheel, from a to b. At the top of the plane, a square hole is dug, the sides of which are lined with masonry, the top being nearly upon the same level as the Rail-road; the wheel is then placed between two frames of timber, the upper of which, ab and cd, is shewn in the drawing. They are kept steady by the diagonal braces e e. The carriages on which the axle runs, are placed on the front of these frames. The upper one at g, and the other immediately below it, on which the ends of the axle that sustains the wheel rests, and on which it is at liberty to run freely round.

At the top of the inclined plane a certain space of ground, for about twenty or thirty yards, (varying according to the number of carriages run down at a time,) is made nearly level, on which the loaded carriages remain until they are to be lowered down, and on which the empty ones stop after their passage up the plane; at the end of this level, or slightlyinclining ground, furthest from the top of the plane the wheel is placed, and small horizontal sheeves, ss ss ss, are placed in the direction the rope runs, to prevent its being injured by dragging along the ground, and also to diminish its friction. These horizontal sheeves are placed at inter

vals of every eight or ten yards upon the plane, from one end to the other. The drawing will show the form of their periphery, on which the rope runs, the width being about four inches; their diameter about eleven inches, with a flange on each side to prevent the rope from running off; they are made most frequently to run upon pieces of wood, and sometimes upon cast-iron stands, placed upright upon the middle of the road; the axles are made of wrought-iron, and when they run upon the upright bearings, about threequarters of an inch diameter. The plane is then made into a proper slope, between the platform or level on which the wheel is placed, and the lower extremity, when a similar flat or piece of level road is made, for the descending train of waggons to land upon. The slope is either uniform, or such as the nature of the ground will permit. Sometimes considerable bends or curves are obliged to be made in the line of the road, but whatever be the form or length of the slope, it must always be terminated at each end by these flat platforms. The narrow parallel lines in the drawing will show the rails as laid down upon the platform; the wheel being placed below the level of the rail: the square hole is covered up, and the rails pass over upon the cover. In the drawing, the rails are broken off at kk, the cover being removed to shew the wheel.

The dotted line A A, may be supposed to represent the one end of the platform, and the top of the plane. Three rails r r'r'' are laid from this part nearly half way down the plane, of the requisite width between each rail, for the carriages to run upon, so that both the ascending and descending train pass upon the middle, and upon one of the outer rails: these are continued to where the one train of waggons have to pass the other. The three rails are then made to branch into four, in the same manner as from A A to B B,

for a certain distance, sufficient to allow the carriages to pass each other; these four rails then converge into two or a single line of road, as shewn at cc, and are so continued to the bottom of the plane, so that the parallel lines, as shewn in the drawing, will represent a complete passing. The empty, or ascending carriages will be at c c when the loaded carriages are at A A, and they will pass each other near D' E'.

In this form of plane, it will be seen that the loaded carriages pass alternately down the sides D' D and E E. For instance, if they commence their descent at D, one end of the rope being attached to them, and the other end being at E' E, at the foot of the plane, and fastened to the empty carriages, the loaded carriages will pass down D' D, and when they arrive at the bottom, the empty ones will arrive at the top, at E. Upon the other side of the plane, the loaded carriages, in the next operation, pass down the side E' E of the plane, and the empty ones up D' D.

Upon the canals, and also on several Railroads, a double line of road is laid from top to bottom of the plane, with a double line of rollers or sheeves; but the reader will perceive that, in most cases, the one above described will answer precisely the same purpose. In very short planes, the obliquity of the road, in passing from a double to a single line, will cause a partial retardation to the carriages, and also additional friction to the rope; but upon long planes this is scarcely felt, and the cost of a double road the whole distance would be considerable.

When the slope of the plane is not uniform, descending more rapidly in some parts than in others, or when the descent is so great as to give more than a requisite preponderance to the moving power, a brake is applied to the periphery of the inclined wheel, to equalize or regulate the velocity of the carriages down the plane; and, in many instances, men traverse the plane with each train of waggons, and apply the brake or convoy of the carriages to check their velocity when required. The brake upon the inclined wheel will be perceived to have no power in checking the velocity of the carriages more than what is equal to the hold the rope takes upon the wheel in passing round its semi-periphery, for if the excess of gravity of the loaded carriages, above what is required to overcome the whole retarding forces, be greater than the hold of the rope, the wheel may be completely stopped, and the rope slide round the wheel, which, in some instances, might be attended with danger. The declivity of the plane should never be so great as to cause such an excess or preponderance of gravity, when such a wheel as this is used.

Many other plans of employing gravity as a moving power, have been resorted to by different persons. In very steep planes, horizontal

rollers, similar to A. B. Fig. II. Plate. IIl have been used; when the descending train unwound the rope from its barrel, and wound the rope upon the barrel of the returning carriage, which was again in its turn unwound by the descending train; in such a combination, the brake could be employed with any degree of force thought proper, as the rope and barrel were one machine, and the rope could not move round without moving the barrel also.*

Skeleton waggons, loaded with metal, are sometimes made use of to overhaul the rope by which the empty waggons were drawn up the plane, and to drag it down the plane again; and also, at the same time, to drag the rope up by which the descending train was lowered, for the purpose of allowing the descending train always to pass down the same line of road, and the ascending train to travel up a different road, each having a separate rope. I do not see, however, that this mode can be of advantage, except under very peculiar circumstances, for the moving power

*The first self-acting inclined plane, erected near Newcastle-upon-Tyne, was by the late ingenious Mr. Barnes, on which the descending train of waggons drew up, out of a pit or well sunk at the summit, a plummet of considerable weight; which plummet, in its descent, drew the empty carriages up the plane.