Page:Report from the Select Committee on Steam Carriages.pdf/21

 will increase with the velocity; that by increasing the breadth of the tires of the wheels, the injury done to roads by great weights may be counteracted. He considers that on a good road, one ton may be safely carried on each inch of width of tire of the wheels.

Mr. McAdam and Mr. Telford have given corresponding Evidence as to the greater wear caused by horses' feet than by wheels of Carriages.

Each of the above Witnesses agrees, that, adding the weight of the horses to that of the Coach, and comparing the injury done to a road by a Steam Carriage of a weight equal to that of the Coach and horses (the wheels being of a proper width of tire), the deterioration of the road will be much less by the Steam Carriage than by the Coach and horses.

As to the injury to roads, which is anticipated from the "slipping" of the wheels, it may safely be left to the proprietors to correct: the action of the wheel slipping involves a waste of power and an useless expenditure of fuel, which, for their own sakes, they will avoid.

Apprehension has also been entertained, that although the peculiar action of the wheels may not be injurious, yet that, from the great power which may be applied, if the Steam were worked at very high pressure, or if the size of the Engine were increased, greater weight might be carredcarried [sic] than the strength of the road could bear.

Undoubtedly, in proportion to the advance of science, will be the increase of weight drawn by an Engine with a given expenditure of fuel; but there are many practical difficulties to be surmounted before the weight so drawn can reach the point when it would be destructive of roads. There are no theoretical reasons against the extension of the size of the Engines. The difficulties, according to Mr. Gurney, are of a practical nature, and only in the difficulty of management of a large Engine." In proportion as we augment the power of the Engines, we must increase their strength, and consequently their weight; the greater weight will be a material diminution of their efficiency. To a certain extent