Mr. Alexander Gordon.
17 August, 1831.
leans to the side farthest from the boat, platting his feet; this is a more destructive action than that of horses' feet on a road.
Have you found that there is any tendency to slip in Mr. Gurney's Carriages in going up a hill covered with new stones?—When the surface of the road is pot firm, there is a tendency to slip; and when I said there was merely a fraction more of injury done by that wheel than by the others. I was taking such cases into account.
Do you think that the injury that Steam Carriages do to the roads will be exactly in proportion to their different weights, taking the same breadth of the tire?—I cannot state the proportion; if you increase the weight, you must increase the breadth of the tire; at different speeds the injury will differ.
Taking the same breadth of tires, and the same velocity, do you conceive the injury to the road increases in exact proportion to the weight; for instance, that a Steam Carriage of two tons will do only half the injury that a Coach of four tons would do?—I do not know that it will be exactly in these proportions, but it will be somewhat similar.
Then supposing that a Steam Coach carrying two tons, had tires of a breadth of three inches, and that a Steam Coach carrying four tons, had the tires of the wheels of the breadth of six inches; do you think that the injury would be proportionate?—I think that there would be nearly the same amount of injury.
Suppose you increase the weight so as to break through the crust of the road?—If you put a very heavy weight, you will break the crust of the road altogether, no doubt.
Do you think that could be obviated by increasing the breadth of the tire of the wheel?—To a certain extent; but you may increase the weight so much as to pulverize the material of the road, even with a broad tire.
Have the observations you have made been founded on actual experiment or not?—It is on observation; I have observed the action of Mr. Gurney's wheels very narrowly on the roads, because I was interested
