17 August, 1831.
in another patent that was to introduce propellers in the middle of the locomotive Engine, as shown in the drawing produced.
Have you observed them under different ascertained weights?—No great variety.
Upon an ordinary road is the injury done by a Stage Coach or by a Steam Carriage so great as to be apparent at each time that Carriage travels along the road?—Whenever you see a mark left by a wheel you are entitled to say there is an injury done to the road to the extent of the rut.
Do you state that if it is merely a mark on the soft surface of the road?—Yes; from the wheel being at all imbedded in the soil; the water gets in and soaks its way through. If it is in frosty weather, the water and the damp get down, and the alternate freezing and melting destroys the road.
In an ordinary road is the impression of the wheel of a Stage Coach upon the solid surface of the road so great as to make the injury apparent every time the Carriage passes over it?—It is apparent to me, because wherever there is a mark upon the road there is a consequent injury.
Whether that mark is merely the impression of the wheel on the soft mud or dust, or by crushing the materials?—Wherever the road is damp the consequence of the mark, hower slight, tends to destroy the road.
Do you mean whether on the soft mud on the road, or on the solid substance?—The road must be destroyed to some extent; I do not say that it is perceptible. If you put out of consideration the surface, the mere mud, it is not perhaps perceptible at the time, but there must be tear and wear going on on the road, or it will last for ever. I do not now talk of the action of the elements.
On what data do you state that the Steam Carriage does not do more injury than the wheels of a Stage Coach?—Because it does not make a deeper rut.
Does either of them make a rut?—If you suppose the road to be a concrete mass, and that there is
