Mr. Alexander Gordon.
17 August, 1831.
merely a little mud and dust on the top of it. I cannot prove that a four-horse Coach does any perceptible injury to that road. I will say also a Steam Carriage will, in a similar case, do no perceptible injury to it.
Of course if the road was composed of solid rock you would not be able to tell whether a Coach of any description had gone over, there being no mark left, bat talking of ordinary turnpike roads, should you be able to trace the indentation that Coach made?—Yes.
Would you not be able to do the same with a Steam Carriage?—Yes; there are some roads in England, a part of the Holyhead road, for instance, so wel made that you cannot trace any vestige of injury done in good weather. A part of Mr. Telford's road there is a concrete mass.
Do you know whether that road has ever been mended since it was first made?—I suppose it has.
Should you not say that the injury done to the road by a Carriage passing over it, depends greatly on the state of that road whether damp or dry, or otherwise?—Certainly.
Are there any states in which a road is placed in which no injury is done by a Carriage passing over it, take the case of a hard frost for instance?—No perceptible injury is done in that case. If the road is so hard that the wheel makes no mark upon it.—But where the road is at all soft, and when the wheel sinks into that road it must tend to destroy the road, if it be merely in mud on the surface of the road, it is making a cistern to hold a puddle of water.
The greatest injury done to the road will be just after the breaking up of a frost?—Yes; or in fact after the effect of the frost, the water having got into the interstices, has been frozen and expanded. When it thaws the road is not so compact, it is soft and pulpy.
That is the state in which the greatest injury will be done to the road by a heavy weight passing over it?—Yes.
Have you ever, in such a particular state of the road, observed the injury done by a Stage Coach
