siderable support to the rails. The scantling of the rails, are five to six inches broad, and seven to ten inches deep; they are not always fastened to the sleepers, with pins of hard wood; the outer side of the rail is squared vertical, the inner side inclined, making it wider at the bottom than the top; a notch is cut in the sleeper corresponding with this form of the rail, into which it is laid, and a wedge being driven against the outer side, presses the bevelled edge of the rail into the notch, and it is thus prevented from rising upwards. This plan was adopted on the railways in the State of Pennsylvania, where railways were first introduced into America. Another mode has been adopted in that state by Moncure Robinson, the sleepers are imbedded deeply in the ground, and thus protected from the feet of the horses and the action of the air; square blocks of locust or other durable timber are attached to them by trenails near their extremities, and projecting above them to the surface; the rails rest in notches cut into these blocks, as previously described, and are kept in their proper position by keys or wedges. In some cases, detached blocks of oak two feet square, are used to support the rails.

The bar or plate of iron, laid upon the top of the rails, is generally from two to two and a quarter inches broad, and half an inch, to five eighths of an inch thick; it is cut off obliquely at the ends, to prevent the jarring of the wheels, by square joints; and is fastened to the rails by iron spikes, mostly about four and a half inches long, which pass through oblong holes pierced in the bars eighteen inches apart. In some places, a small piece of sheet zinc, is placed beneath the ends of the iron rails, to prevent them sinking into the wood.

§ 2.-Cast-iron Rails. Plate Rail.

We have previously stated, that cast iron was first adopted for rails about the year 1767; Figs. 5, 6, and 7, Plate I., shew the form of these rails, used by Mr. Curr for an underground railway, at the Duke of Norfolk's colliery near Sheffield, in 1776, and which were called the "plate rail." These rails, as shewn in the plates, consist of a flat bar of cast iron, c e, with an upright ledge, cd, for the purpose of keeping the wheels upon the line of the former; they were generally made six feet long, the flat part of the rail and upright ledge being each about two inches; near the ends of the rail small holes were cast in the base, through which nails or wooden pins were driven into the wooden sleeper shewn at b'b', the latter being generally of the same description, as those used in the wooden railway previously described in Figs. 1 and 2.

As shewn in Figs. 5 and 6, the joinings of the rails were quite square, two pins, b'b', being used at the joining, and one pin, b, at the intermediate sleeper.

Various forms of this kind of rail have been used, either with wooden sleepers, stretched across the whole breadth of the railroad, as in Figs. 1 and 2; or with square wooden sleepers, as shown in Figs. 5, 6, and 7, on which the rails were nailed.

In the year 1800, we are told that Mr. Benjamin Outram, an engineer, in adopting this rail on the public railway at Little Eton in Derbyshire, first introduced stone props instead of timber for supporting the ends, and joining of the rails.

Mr. Outram, however, was not the first who made use of stone supports, as the late Mr. Barns employed them, in forming the first railroad which was laid down in the neighbourhood of Newcastle-upon-Tyne, viz., from Lawson Main colliery, to the river, in 1797.

This kind of rail, has undergone many alterations in form, since it first came into use.

Fig. 8, Plate I., is an elevation, Fig. 9 a plan, and Fig. 10 a section, of the most improved form of this kind of rail; cc cc, are the rails placed upon stone supports, as shewn in Figs. 8 and 9, at the ends of each rail, where they are laid against each other on the stone support; a small square piece is left out in casting the metal, increasing in size upwards, or bevelled, so that when the two ends are laid together, they form a square hole through the ends of the rail, narrowing downwards; a perfectly level, or horizontal groove is then made on the top of the stone, and the rail imbedded on it; a hole larger than the square hole of the rails is drilled into the stone about half the depth, into which is inserted a wooden plug, shewn at g, Fig. 8, and an iron pin, b, is then driven into this plug through the hole in the rails; which pin, having a bevelled head, fastens them down to the stone, one half of the pin securing one rail, and the other half the adjoining rail, as shewn in the drawing; these rails are generally from three to four feet long.

Fig. 10, is a section of the rail; ad, the base of the rail or wheel-track, about four inches broad and an inch thick, and which is made quite level; de, the flange or upright ledge to keep the wheel upon the base, a d, of the rail; and a fa, Figs. 8 and 10, the flange projecting downwards to strengthen the rail. The upright flange, is the same height throughout the whole length of the rail, as shown in Fig. 8 or 10, being no higher than is necessary to secure the wheel upon the proper track, and which of course, requires no greater depth in one part than another; and the height adding to the friction of the carriage-wheels, it should

therefore be made as low as possible; hence, we find it never exceeding three inches.

This restriction in the height of the upright ledge limits the form of the section, and renders it not that of the greatest strength, the resistance to fracture being, as the breadth and square of the depth; the horizontal part, ad, of the rail, while it adds to the weight and cost, does not in the same degree add to the strength, the upright section, de, being the only part in that position, which presents the strongest form of section; this, however, as previously stated, being limited in height, a downward projection has been cast upon the opposite side of the bearing section of the rail, shewn by af, Fig. 10, and a fa, Fig. 8. The form of this projection, as shewn in the latter figure, is such as to secure equal strength in every part of the rail, being deeper in the middle, f, and tapering away in a parabolic, or semi-elliptic form, in both directions, to the ends of the rail.

This form of rail, with very trifling modifications, constitutes the most modern plate rail; until very lately, they were universally made of cast iron, but about the year 1824, some were formed of wrought iron; and at present almost all the rails of this description, used in the collieries in the north of England, are made of wrought iron, rolled into the form shewn in Fig. 5.

These rails, have generally been laid down either upon transverse sleepers of wood, as in Figs. 5, 6, and 7, or upon stone blocks, as in Figs. 8, 9, 10; but they have been laid, in some instances, upon cast-iron sleepers, stretched across the whole width of the way. Fig. 11 shews a section and plan, of this kind of sleeper and rail; a a a is the base of the metal sleeper, a longitudinal cavity is cast at each end of the sleeper at cc, with a raised part

on the inside, at bb; within this recess or cavity, the rail is laid, and a wedge being driven between the upright ledge, bb, and the back of the rail, it is thus secured to the sleeper. This plan has not been much used, the great expense of the cast-iron sleeper operating much against its adoption.

The great objection to the plate rail, is the friction of the wheels, against the upright flanch; and the liability of the bearing part, to receive the dust and mud of the road and wheels, which its form renders it peculiarly liable to, and of which no care can prevent the accumulation.

§ 3.-Cast-iron Rails. Edge Rail.

Soon after the introduction of cast-iron rails, a form of rail, called the "edge rail," was brought into use. Mr. W. Jessop, in 1789, formed the public railroad at Loughborough, with this kind of rail; the upper surface of which was level, and the under section, of an elliptical figure; and as the rail itself, did not present any means of keeping the wheel upon it, a flanch was cast upon the wheels, to guide them along the top of the rail.

In the wooden railways, the upper rails being convex on the surface, upon one side of the periphery of the wheels, a flange projected downwards, about an inch, which served to keep the wheels upon the rail; when the plate rail was introduced, the form of the periphery of the wheel was altered, being made quite flat and of less breadth; and again, when the edge rail was introduced, the rim of the wheel was brought back to the same form, as that for the wooden railway.

A A, Fig. 1, Plate II., represents an elevation or side view; and B B a section of the edge rail. It consists of a bar of cast iron, from three to four feet long, and about one half or three quarters of an inch thick, swelling out