Remarks on the Present System of Road Making / With Observations, Deduced from Practice and Experience, With a View to a Revision of the Existing Laws, and the Introduction of Improvement in the Method of Making, Repairing, and Preserving Roads, and Defending the Road Funds from Misapplication. Seventh Edition, Carefully Revised, With an Appendix, and Report from the Select Committee of the House of Commons, June 1823, with Extracts from the Evidence

by John Loudon McAdam

That is, provided the substratum is sound?—No; I should not care whether the substratum was soft or hard; I should rather prefer a soft one to a hard one.

You don’t mean you would prefer a bog?—If it was not such a bog as would not allow a man to walk over, I should prefer it.

What advantage is derived from the substrata not being perfectly solid?—I think, when a road ts placed upon a hard substance, such as a rock, the road wears much sooner than when placed on a soft substance.

But must not the draught of a carriage be much greater on a road which has a very soft foundation, than over one which is of a rocky foundation?—I think the difference would be very little indeed, because the yield of a good road on a soft foundation, is not perceptible.

To use the expression to which you have alluded, as being used by the coachmen, would a carriage run so true upon a road, the foundation of which was soft, as upon one of which the foundation was hard?—If the road be very good, and very well made, it will be so solid, and so hard, as to make no difference. And I will give the Committee a strong instance of that, in the knowledge of many gentlemen here. The road in Somersetshire, between Bridgewater and Cross, is mostly over a morass, which is so extremely soft, that when you ride in a carriage along the road, you see the water tremble in the ditches on each side; and after there has been a slight frost, the vibration of the water from the carriage on the road, will be so great as to break the young ice. That road is partly in the Bristol district. I think there is about seven miles of it, and at the end of those seven miles, we come directly on the limestone rock. I think we have about five or six miles of this rocky road immediately succeeding the morass; and being curious to know what the wear was, I had a very exact account kept, not very lately, but I think the difference is as five to seven in the expenditure of the materials on the soft and hard.

Do you mean seven on the hard and five on the soft?—Yes.

And yet the hard road is more open to the effect of the sun and air than the soft road?—It certainly lies higher.

Have you ever inquired of the coachmen, on which of those two descriptions of roads the carriages run the lightest?—Yes, I have; and I have found that there is no difference, if the road be equally smooth on the surface, whether it be placed on the soft ground or hard.

But in forming a road over a morass, would you bottom the road with small or large stones?—I never use large stones on the bottom of a road; I would not put a large stone in any part of it.

In forming a road across morass, would you not put some sort of intermediate material between the bog and the stone?—No, never.