suitable pulling instrument at all; it is only a rolling instrument for reducing friction, and was never intended for anything else.

The sketch or drawing, Fig. 3, will best show how the required conditions have been carried out.

A is a disc keyed or fastened to the driving axle; mounted in the disc are sixteen sliding spokes, and on the outer end of each spoke is a foot, B, pivoted by a balland-socket joint so that it can turn to any reasonable angle to suit the surface of the road. On one side of each spoke, and projecting beyond the disc, is a small

wheel, or roller, C. The spokes are drawn inwards by springs (one to each spoke) on the other side of the disc, radiating from the centre. These springs are not shown in the drawing.

Mounted on the axle-box I is a rail, D, pivoted to a flat plate or guide, E, forming part of the axle-box; the pivot of the rail is free to rise and fall in a slot, F, in the plate E. The rail D supports the engine or vehicle by two springs, G, pressing against a top lever, H, pivoted to the top of the axle-box I. The two inner springs, J, only serve to steady the top lever, H. Two guides, K, are provided to lead the rollers C under the rail D.

The whole of the levers and springs mounted on the axle-box come flat against the disc A, so that the rollers C, which project from the disc A, are arranged round the guides K and the rail D, as shown.

The disc A, carrying the spokes, rollers, and feet, revolves, but the axle-box I, with its dependent lever, guides, rail, and springs, does not revolve, with the result that a roller starting from, say, the top of the disc, strikes on the guide K, and gradually forces the sliding spoke outwards, thereby enabling the foot to turn on its ankle-joint by its own weight as it comes down, and to drop with its flat surface on the road, the roller then passing under the rail as shown. The bottom of the rail is slightly arched, as shown by the dotted line, so that the varying height of the rollers caused by the spokes being sloped or upright is neutralized, and the soles of the feet present a uniform level surface to the road.

Practically the Pedrail system places feet on the ground, each foot supporting a roller on edge, and a short

rail, supporting the load, is levered along by the spokes over the rollers.

In an ordinary railway a rail is laid down and wheels are run over it; in the Pedrail, wheels, or rollers, are laid down and the rail is run over them. The principle is the same, only the railway is inverted. The sliding spoke represents the horse's leg, or lever, and each leg is pivoted by an ankle-joint to its foot.

By turning the railway upside down, the parts coming in contact with the road are broken up into a number of comparatively small feet, which can twist in varying directions as required. Previous attempts at endless railways have failed owing to the attempt to place the rail next the ground. The rail, presenting a long cumbersome surface to the road, did not lend or adapt itself to the varying inequalities of the road surface, and hence caused endless breakages and repairs.

In Fig. 3 three feet are shown in contact with the road, and it will be seen that as the Pedrail moves forward one of these feet is lifted up before the corresponding foot at the other end of the rail comes down; in other words, each Pedrail has two and three feet alternately on the ground, and if this is combined with the fourwheeled-driven traction-engine already described (i.e. four Pedrails), the number of feet on the ground per engine would never be less than eight, and might be twelve, or an average of, say, ten. Each of these feet on a full-sized Pedrail is about 9 inches in diameter, the feet being circular on plan to admit of their turning round when turning corners, etc.

Compare this surface contact of 10 feet, each 9 inches

in diameter, with that obtained in a two-wheel-driven traction-engine, as shown in Fig. 4, in which the point of contact is quite small and inadequate. By using four Pedrails the proportionate surface adhesion is so enormously increased that the slipping of the driving-wheels, so well known as the great traction-engine problem, would in the Pedrail system be practically an impossibility.

FIG. 4.

Attention is here drawn to a theory, which the author believes has not hitherto been advanced, viz. that a wheel in rolling on the road compresses the road by what may be described as a series of infinite gradations, aptly illustrated by the squeezing action of the ordinary mangle. In other words, a road that would be strong enough to support a given weight spread simultaneously over a large area is unable to withstand the pressure which attacks it piece-meal. In Fig. 5 the shaded portion represents the section of a soft road that has been squeezed into a wedgeshaped wave in front of a wheel. It is clear that the compression of the road particles is greatest at the

point A, and therefore that the density of the wedgeshaped wave lessens from A to the point B, where it is theoretically softest. The wheel in rolling, however, commences its attack on the road at this softest point, B, gradually creeping forward inch by inch and mangling it down to the density of A. Compare this with Fig. 3, in

which there is no rolling motion on the road at all, and in which no wedge-shaped waves are possible; the rolling movement is in the inverted railway at a higher level. The feet come down at intermediate intervals, each foot covering a large surface simultaneously, and they act like rammers, falling and rising almost vertically. Even with the same area of contact the supporting power of a road is thus very different when subjected to a ramming as compared with a rolling or mangling pressure.

Moreover, any one foot alighting on a sufficiently

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