on this power were made by the direction of the commissioners for the Holyhead Road, with a view to ascertain the best mode of constructing and repairing that road. The result of these experiments shows that the power of traction over a level well-constructed pavement, varies from 32 to 39 lbs. for every ton. A waggon, weighing 21 cwt. 8 lbs., drawn over a well-laid pavement in Piccadilly, required a power of traction, varying from 33 to 40 lbs. In a place where the pavement was uneven, and worked into holes, the power was increased to 48 lbs.; but it may be assumed, that the power of traction on the best laid pavement—such as that which may be seen before the new buildings in the Strand, and in Parliament Street, when newly paved is at the rate of about 32 lbs, to the ton. On a broken stone surface of old flint road, the traction is about 64 lbs., being double that of a pavement. On a gravel road, the power of traction is nearly 150 lbs, to the ton; on a broken stone road, having a rough pavement foundation, the traction is 45 lbs, to the ton.
From these results, it appears that Mr. Gurney's estimate of the comparative traction on railroads and common roads is not supported by experiment. The traction on a railroad being about 9 lbs, in the ton, and that on the best laid pavement being 32, the latter is three and a half times the former. The traction on a well-made stone surface of old flint road is about seven times the traction on a railway. On a gravel road, it is about fifteen times, and on a broken stone road, with a rough pavement foundation, it is about five times the traction of the railway. I may not be, perhaps, far from the truth in assuming that the average traction of level turnpike roads, in the summer or frosty season, is about twelve times that
