Page:Report from the Select Committee on Steam Carriages.pdf/213



Mr. John Macneil. 6 September, 1831. as far as it was affected by the wheels of the Carriages, probably rather less, by the Carriage carrying four tons, on four-inch wheels, than by the Carriage carrying two tons, with two-inch wheels; but it must be recollected that both the Carriages are supposed to be drawn by the same number of horses, and as the horses drawing the Carriage of four tons must use greater exertions than those drawing the Carriage of two tons. I am of opinion that the aggregate wear of the road would be more by the transit of the four ton Carriage, than by that of the Carriage weighing two tons.

How would the foregoing answer be affected by an increase or decrease of velocity in either Carriage?—If the road over which the Carriages are drawn be hard, solid and smooth. I think there would be very little increase of wear from the effect of the carriage wheels by an increase of velocity; but if the road should be uneven or rough, there would be an increase of wear, in consequence of the impetus or blow with which the wheels would strike the road, after passing over the inequalities in its surface, particularly if the Carriages were made without springs; but whether the road be a good or a bad one, the wear occasioned by the feet of the horses will be greater when they travel with an increased velocity; for a coach-horse which travels at the rate of ten miles an hour, works on an average 270 miles in a month, and wears out in that time about four pounds of iron in shoes; whereas a waggon-horse, which travels at the rate of three miles an hour, and works twenty-six miles a day, for four days in the week, goes, on an average, 416 miles in the same period of time, and wears out 4.8 pounds of iron. If the coach-horse travels the same distance, the wear would be six-sixteenths, which exceeds the wear of the waggon-horse one thirty-sixth. In the same way might the relative injury caused by the wheels of the Waggon and the Coach be ascertained.

What is the operation of the atmosphere on roads?—Well made roads, formed of clean bard broken stone, placed on a solid foundation, are very little affected by changes of atmosphere'; weak roads, or