your

reference to new roads in this country, it seems to be opinion that the assistance of engineers should be more generally called in?-Clearly so; recourse ought to be had to the very first scientific and practical skill of the country; it requires the first civil engineers that can be found.

That applies to putting the existing roads into good repair, independently of making new roads, does it?— Either; but more especially in making new roads.

With regard to the present roads; will they not require considerable improvement in order to render them any thing like what you say a road ought to be ?-Undoubtedly they would; even supposing you were not to deviate a single foot from the existing roads, a large portion of them would require re-constructing.

Would that be with reference to hills?-No, I mean with respect to the structure of the road itself; the structure of the crust.

It diminishes the hardness so as to leave the tractive force much greater than it ought to be?-Just so.

Is that a common fault in roads?-That is a very prevalent fault.

Then with regard to hills; would you do any thing with regard to them?—There is a great deal to be done with regard to them.

Still more, perhaps, if it were determined that we were to have roads in the best direction?-I should say, if you were to take any two particular points in England, and were to take the first engineer you could get, and say to him, make the best road between such and such places, without the slightest regard to existing roads, I do not think he would coincide, except by accident, with any of the existing roads; it would be laid down on a totally different principle to what the present roads are laid

down upon; the present roads are a series of shifts and expedients which the road-makers have adopted from time to time, without regard to the general scientific principles.

What do you suppose to have been the motives with which the present roads have been laid out in the present lines?-Originally the old horse-paths of the country were followed; and we have kept in the old line of road as long as we can, without great disadvantage. You may observe the most glaring defects take place: you make an occasional deviation with a view to improvement, but return to the original line. There is scarcely an example of one continued line of road, of any length, laid down from end to end on any intelligible principle.

If any plan were attempted by the Legislature for the improvement of the roads in their present state, it is decidedly your opinion that it ought to be conducted under the management of the most experienced civil engineer that this country possesses?—I am quite decidedly of that opinion.

The surveyors generally of roads do not belong to the profession of engineers ?—No.

And engineers have not generally been employed in laying out roads?-No; the only cases, and the only species of roads in which great engineering skill has been called into play, are generally the railroads; and even in these there is a great dearth of it.

Are you acquainted with the roads in the Highlands?— Yes.

I would wish to ask you a question about the elasticity of the road. How can it be proved what the elasticity of a road is; take Regent-street for example, at four o'clock in the morning, when there are no persons there; you say it has been ascertained that there is an elasticity

in almost every road; I wish to know whether there is any scientific mode of proving that elasticity?—If the elasticity be considerable it will be almost visible; you will almost see the surface yield under the wheels; but if it is less, we have no other means of proving it except by the tractive power.

There has been such a thing as proving the elasticity of a suspension-bridge by a succession of telescopes?—That may be; but it is taking elasticity upon a very extensive scale.

Now take a hard granite road, for instance near London, of which the material is ten inches thick, and which is dry and impenetrable by water, do you conceive that there is any elasticity in a road of that description?-Ten inches is a very considerable thickness for a road-crust of granite; and, if the subsoil be firm and hard, I dare say that that road would be very hard without applying Mr. Telford's method.

Do you mean it would have no elasticity?-It would have very little elasticity.

Does not the tractive power depend, in some measure, upon the friction of the wheels?—The tractive power depends partly upon the carriages; it is different with different carriages; it depends upon the asperities of the roads being encountered by the tire of the wheel; and then, lastly, it depends upon the softness or yielding quality of the road.

Of what stone do you conceive the smoothest surface could be made?-I am scarcely sufficiently acquainted with that subject to answer the question.

Do you think that stone which possesses the greatest smoothness of surface would make the best surface?-I think it would, unless it were deficient in durability.

Is it not apparent that the softest stone would wear into

the smoothest surface sooner than an extremely hard stone?-Yes.

Would you recommend a road to be made of that stone?--I should recommend that the upper stratum of the road should be made of that stone which would wear the smoothest; and that the under stratum should be made of the more durable stone.

You have not probably applied much attention to the effect of different sorts of stones with respect to their smoothness and hardness, and their general effect upon the force of traction?—No, I have not.

I would wish to ask you a question with respect to the vibration upon a road; you stated that you considered the vibration a great repellant to the tractive power; now, in going over a moss, for instance, where there is an evident vibration, do you consider that that vibration is repellant to the tractive power?-I suppose that vibration to be identical, in fact, with what we have been calling elasticity.

Assuming your definition to be correct, that vibration and elasticity are the same, I would wish to ask you whether there would be more vibration or elasticity in a pavement than in a road?-There would be less in a pavement than in a road.

It has been observed in London that a house shakes more from a carriage going along the pavement than it does when the carriage goes along a macadamized road? -That is from the percussion. I should state, perhaps, in speaking of pavement, that good pavement offers the least resistance to the tractive force. I should say that the pavement of the Strand or Fleet-street, when in good order, approaches as near to a railroad as any thing can do.

In a well constructed pavement, such a pavement as

you

have alluded to, the more the masonic skill the less the percussion, and the greater the facility, is it not?— Yes.

Therefore the great desideratum in paving is that there should be a very well constructed masonic arrangement?— Yes; but it is surprising, and you would scarcely believe it without a knowledge of the fact, the extent to which that, which has been called vibration, exists even on a railroad. I have experimented on a railroad for the purpose of feeling its surface as well as I could. I have gone in carriages without springs, and it is impossible to convey to you the intolerable sensation I experienced. I thought every limb in my system would be shaken to pieces; and that is the case even over the best railroads. It was produced partly by the joints of the rails on the chairs; there is also, however, some unevenness in the surface of the rail which you can scarcely be aware of; but it may be seen in this way. If you go to a railroad after a heavy shower of rain, and before the wet fully dries, and stand with your face to the sun, so that the rays of the sun striking on the rails will be reflected on the eye, you will see plainly all the unevenness on the surface of the rails, and you will see that they are not inconsiderable.

Have you at all calculated the amount of friction produced by curves on a railroad?-The amount of that friction depends upon the velocity with which the carriage goes, and on the radius of the curve; the friction increases in the same proportion as the square of the speed; that is to say, if you double the speed it will give four times the resistance; and if you treble the speed it will give nine times the resistance, and so on in proportion. It also depends upon the radius of the curve, and it is inversely in proportion with the radius of the curve; the less the radius of the curve the greater will be the resistance.