Page:Report from the Select Committee on Steam Carriages.pdf/132



Mr. Richard Trevithick. 12 August, 1831. but the greatest folly I have ever seen is the wide waggon wheels which go free of turnpike duty, one part is nine feet round and the other part not above seven and a half or eight feet, one part is going faster than the other, and the one part must rub; had the wheel been upright and it was turned off, the point only would meet, but it would not be rubbing.

There is a particular width of wheel in which no injury will be done to the road, but rather good?—It will be rather good after the road has been mended to settle it down; there will be wear in it as at other times; but in certain states of the roads to settle them down they will be doing good, but at no state of the road could it do good with narrow wheels.

What would be the effect when the road was once settled?—You see very often roads which have been gravelled; in dry weather the dust blows away; they can never settle again, but if the broad wheels passed over to crush it over with the dust, it would settle down much firmer; but the narrow wheels slide so easy through that they sink down, and shove them on each side.

Is there any state of the road in which you think a wide wheel would do injury to the road?—No; there is no state of the road in which wide wheels will do an injury; if there was to be a wheel of an inch in diameter instead of six inches, it would be like a stamping wheel cutting the road constantly, but the width of the wheel takes off that; the tenacity of stone is equal to the weight.

Does not the whole of this refer to wheels that are cylindrical and the axles horizontal?—Yes, they ought to be straight; that is the very wheel which I want for a Steam Carriage with straight axles.

Is not the road injured in two ways by the wear of it, and by the separation of the materials?—The separation of the materials is not so likely to take place with wide wheels as with narrow.

That is the reason why narrow wheels injure the roads more than wide wheels?—Yes; and there is a much greater weight upon one pebble than is thrown on two or three, double the weight is thrown on one pebble than would otherwise be; then that pebble is