The rails forming the inner part of a curve, should be fixed a little lower than the other, and the rails set a little under the gage, so as to bring the sides nearer together than in the straight parts. It is certainly a great inducement to give the flat rails a preference to the edge ones, that their wheels are suitable for travelling, either on the railways, or upon common well kept hard roads. In the account given of the Surrey railway, which is 26 miles in length, it is said, "The rail-wheels are 2 feet 5 inches high, the felloes or rims of the wheels are 2 inches broad, and nearly as thick, with 12 spokes; the sharp angles are rounded off, so that these wheels are capable of being used without damage on any hard common road, a very principal advantage attending the mo dern use of railways. The axles of the wheels are fixed at 2 feet 7 inches distance, the waggons are 7 feet 9 inches long, 4 feet 5 inches wide, and 2 feet 4 inches high; the weight of the above waggon is 31 tons."

To meet the opinion of those who are partial to the action of narrow surfaces, the flat rail-wheel may be made 3 inches broad in the felloes, and ths of an inch, bevelled away to each side, leaving a space of only 1 inch in the middle, to roll upon the flat rail, being equal to the common breadth of edge-rails, and which would not prevent them from travelling on common roads, as the rings of all wheels soon wear circular across. Diagonal brushes may be so suspended to a gang of waggons, as will, without the aid of the waggon-driver, clear the flat rails of small

stones and gravel, and diagonal scrapers may be used in place of brushes, in wet weather. To deepen the horse-track of flat rails, whose ledges are on the inside, and to make the ledges somewhat higher, would tend much to prevent gravel and small stones from lodging upon the rails; and would not occasion a horse, of the height generally used for waggons, to travel below the best line of draught, which is, when the traces form an angle of about 18 degrees with the line of the road. When the horse-track is made deep, gutters ought to be cut along-side of the railway, somewhat deeper than the horse-track, and covered at the passing places; outlets should also be made under the rails on each side to let off the water from the horse course in wet weather.

Experiments were made on Mr Wilkes of Measham's railway, near Loughborough, when a moderate sized horse, in the presence of a Committee from the Society of Arts, did draw upon it with ease, down hill, (the descent being one foot in a hundred) 30 tons, and 7 tons up hill, independent of the carriages. In the Philosophical Magazine for July 1811, are the following remarks on waggons and rail-roads: "The waggons on our cast-iron rail-roads have not received the improvements of which they are capable; but with their present disadvantages, the following facts will evince the great saving of animal force to which railways have given rise; first, with a declivity of 1 inch per yard, one horse takes downwards three waggons, each containing 2 tons; second, in another place, with a rise of 1ths of an

inch per yard, one horse takes 2 tons upwards; third, with 8 feet rise in 66 yards, which is 11ths of an inch per yard, one horse takes 2 tons upwards; fourth, on the Penrhyn railway (same slope as above), two horses draw downwards four waggons, containing 1 ton of slate each *; fifth, with a slope of 55 feet per mile, one horse takes from 12 to 15 tons downwards, and 4 tons upwards, and all the empty waggons; sixth, at Ayr, one horse draws, on a level, 5 waggons, each containing 1 ton of coal; seventh, on the Surry railway, one horse, on a declivity of 1 inch in 10 feet, is said to draw 30 quarters of wheat."

The formation of roads, and the preparation of road-materials not being altogether foreign to that of rail-roads, it was intended to give some account of the principles of machines for breaking new quarried stones (not boulders) of all sizes, from that of 2 stone weight down to any required size for the formation of roads, the machines to be wrought by water, steam, wind, or animal power. Sketches of these machines were shewn to a scientific friend, so long ago as 1806; but having lately seen it mentioned in the newspapers, that Messrs Kay and Routledge have mounted a machine for breaking stones for roads

At Penrhyn railway, the horses are usually worked three in a team, and generally take down about 20 waggons, containing each one ton of slates, exclusive of their corn-chest and a barrel of water for wetting the rails, to render the draught more easy, Editor of this article.)

between Bury and Bolton, wrought by a rotatory steam-engine, it is thought unnecessary to enter, at present, upon the subject of roads, or that of the preparation of road materials.

Some of the most celebrated Engineers have given it as their decided opinion that railways are preferable to small canals. Railways may be constructed in a much more expeditious manner than navigable canals; they may be introduced into many districts, where canals are wholly inapplicable; and in case of any change in the working of mines, pits or manufactories, the rails may be taken up, and laid down again, in new situations, at no' very great expence.

The subject of rail-roads is far from being yet exhausted; and it certainly deserves every possible consideration. There is no plan, scheme or undertaking, that would lead to more extensive and permanent improvements, than that of extending branches of railways, from public lines, to all the improveable uncultivated districts in the kingdom; which, in time, would become a source of national wealth, and afford permanent and profitable labour for all out of employment.

For the historical part of this Essay, see Rees's Cyclopædia; Brewster's Encyclopædia; English Encyclopædia; Curr's Coal Viewer; Holmes on Coal Mines; Aiton's Agricultural Report of Ayrshire; Observations on a General Railway, published by Baldwin, Cradock and Joy, London, 1821; Adam's Lectures by Jones; Aitken's Picture of Newcastleupon-Tyne, 1812; Smith's Mechanic.

Remark.-Mr Scott, the author of the foregoing essay, has been at much pains in visiting the principal railways in Scotland, in consulting works which treat upon the subject, and in preparing drawings and models for illustration. It may, however, be proper to mention, that although the suggestions contained in his essay are ingenious, and may turn to useful account, yet the Editor of this article would not be understood as giving any opinion as to their application in practice.

ESSAY by MR GEORGE ROBERTSON, BowerLodge, Ayrshire.

The first mode of conveying goods, by the aid of machinery, would, in all probability, be by dragging them on sledges. This manner of conveyance is generally conceived to double the power of carriage,-requiring only one pound weight to drag two along a level surface, and hence there is evidently a saving equal to one-half, when compared with carrying the burden on the shoulders or in the hand.

*This, although a general notion, does not hold uniformly true. It depends, in a great measure, on the state of the roughness or of the smoothness of the materials to be dragged along. Thus I have found, that, whilst a piece of unpolished cast-iron required one-half of its own weight to pull it along a smooth deal; yet a piece of the same metal polished, and a piece of polished marble, were each dragged along by a weight not exceeding one-third of their own.

VOL. VI.

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