of the rails. The bed for the sleeper is usually the dry ballasting of the railway, the broken stones being levelled quite smooth before the sleeper is laid in its place. It was till lately the practice to kyanise* the wood sleepers; but this has been greatly superseded by the newer inventions, formerly alluded to, of Mr. Payne, for abstracting the juices and air from timber, and those of Sir J. Burnett. In many instances, however, sleepers of well-seasoned larch are laid without any preparation. The size of the transverse sleepers on the London and Birmingham line is 7 feet long, with a scantling 9 inches by 5 inches; on the London and South Western, cross sleepers throughout 9 feet long, scantling 10 by 4 inches; Edinburgh and Glasgow, 9 feet long, scantling 10 by 4; Manchester and Birmingham, 9 feet; Manchester and Leeds, 9 feet, scantling 11 by 5; Midland Counties, 9 feet, scantling 10 by 5; North Eastern, 9 feet, scantling 10 by 6; North British, 8 feet 6, scantling 9 or 10 by 4 or 5.

Railways formed entirely on cross sleepers are much more common now than formerly, both in this country and abroad. Several lines indeed, which were formerly laid with stone blocks, have been relaid with wooden sleepers. The Belgian

*

Kyanise, to prepare timber with Mr. Kyan's patent solution.

railways are entirely laid on wood. In this country, on some lines, transverse wood sleepers have been laid down throughout the line, as on the London and South Western, the North Eastern, and others; and several of the lines now forming, are being laid entirely on cross sleepers, as the North British, and others.

There still, however, hangs over this point of railway formation considerable uncertainty; for although on one line stone blocks may be entirely removed, and timber substituted, on another the reverse of this has been the case, from the decay of the wood. Cross sleepers too, unless they have sufficient scantling, and are considerably wider than the gauge of the rails, are liable to be displaced by the least sinking of the ground; and as there is nothing to prevent the sleepers from rising but the ballasting, this plan cannot be deemed perfect. It has, however, become extended, from its cheapness and facility of execution, and diminution of rigidity.

The London and Greenwich railway affords a good example of the smoothness attending the use of timber bearings. Had the rails been laid on stone blocks upon the viaducts, it must have much increased the harshness of motion.

Some attempts have been made, both in this

country and in America, to introduce the use of stone blocks in the same manner as transverse wood sleepers are laid; proceeding on the idea, previously noticed, that their parallelism was less likely to be disturbed, or the rail thrown out of gauge, from any inequality or yielding of a block, than when laid in the common manner. The Dublin and Kingston railway was laid on thoroughgoing blocks of granite of this kind, 6 feet long, 2 feet wide, and 1 foot thick: these were laid across the way, at 15 feet apart, and intermediate single blocks of the ordinary kind were placed between them, at the distance of 3 feet. Probably, from the difficulty found in adjusting properly the bed for such heavy blocks, and from the vibration and jolting of heavy trains on a hard bed, and breaking of the long blocks, the plan turned out a failure; and the stone blocks have been entirely taken up, and timber substituted. Sometimes transverse sleepers made of cast iron have been used in place of timber. Cast-iron bed-plates have also been proposed, instead of stone blocks; but it is considered iron has too much rigidity for these purposes.

In the United States, transverse stone blocks were tried at the Boston and Lowell railway: the blocks were made of granite, 6 feet in length,

F

and 18 inches square, and placed at 3 feet apart, centre to centre, each block supporting both rails, the gauge being 4 feet 8 inches. This plan was found, however, to produce too rigid a road. In some instances, to attain a greater connection between the blocks when placed separately, iron tie or connecting rods have been used at

curves.

SEATING THE CHAIRS UPON THE BLOCKS.

When the blocks and sleepers have been placed along the line of a road, the next thing is to set the chairs, or pedestals, which are to support and fix the rails. These are usually made of cast iron, for convenience, on account of the irregularity of shape. Malleable iron is, however, much stronger; but though a patent has been obtained for making them of it, they have not been yet introduced. As great a variety of forms has been proposed for chairs, as for rails, because the former must be adapted to the latter. The chair generally stands vertically, having an open socket or groove to receive the rail, the base of which being, when set in the chair, about an inch clear of the block or sleeper. The distances the chairs are placed apart, are of course regulated by those of the blocks: they are fixed to the blocks in the following manner :

Holes are drilled in the stones, from 1 to 2 inches in diameter, into which plugs of oak, or tree-nails, are driven; and the chair being placed on its seat, and accurately levelled, iron pins or spikes, with heads, are driven through the holes in the base of the chair, into the wooden plugs, which fixes the chair fast to the block. When chairs are to be fastened to wooden sleepers, the ends of the latter are cut to the proper level, and the chairs are nailed down with strong spikes. There are usually two perforations in the intermediate chairs, as on the North British railway; but on some railways the chairs have three, as on the London and Brighton; two on one side, and one on the other. The holes are sometimes placed diagonally, and generally so in the joint-chairs.

The weight of the chair is regulated by the size and strength of the rail, and both are made much heavier than formerly. The 76 lbs. rail on the London and Brighton railway has a chair at the joinings 10 inches wide by 5 inches high, and the intermediate chairs are 10 by 4 inches. The chairs on the North British railway are 10 inches wide, 5 inches high, 5 inches broad, and the intermediate ones 10 inches wide, 5 inches high, and 4 inches broad.