carriage (which may be taken at from 1_s._ 6_d._ to 2_s._ per ton per mile) from any distance, to make it preferable to the gravel, or paving, in point of cost, for the roads near London. A double iron rail-road, to suit the London waggons, which some have recommended, would cost about 4,500_l._ per mile, and would be fitted for waggons only of one precise width, and for waggons or heavy carts only; while, from the difficulty of crossing it, it would form rather an obstacle to light carriages. Blocks of Aberdeen granite, twelve inches wide and fifteen inches deep, laid in the way of the wheels (as recommended by others,) would be nearly as expensive; and the eight joints, which would be formed between the stone and the gravel, by four rows of stone, would be found extremely troublesome and inconvenient. Both these substitutes for paving, therefore, though equally expensive as paving, have peculiar disadvantages; and they have this besides, which is common to them both, that they make no provision for preventing the great wear upon gravelled roads, which is caused by the horses’ feet, particularly if (as is the case in a rail-road) they are confined in one track. Attention in the forming and repairing of roads, will in all cases do much to compensate for the inferiority of the material used for that purpose, of which the improvements in the general state of the highways within the last twenty years affords the best proof. To form the road upon a good foundation, and to keep the surface clear of water after it is formed, are the two most essential points towards having the best roads possible, upon a given country, and with given materials. For obtaining the first of these objects, it is essential that the line for the road be taken so that the foundation can be kept dry either by avoiding low ground by raising the surface of the road above the level of the ground on each side of it, or by drawing off the water by means of side drains. The other object, viz. that of clearing the road of water, is best secured by selecting a course for the road which is not horizontally level, so that the surface of the road may in its longitudinal section, form in some degree an inclined plane; and when this cannot be obtained, owing to the extreme flatness of the country, an artificial inclination may generally be made. When a road is so formed, every wheel-track that is made, being in the line of the inclination, becomes a channel for carrying off the water, much more effectually than can be done by a curvature in the cross section or rise in the middle of the road, without the danger, or other disadvantages which necessarily attend the rounding a road much in the middle. I consider a fall of about one inch and a half in ten feet, to be a minimum in this case, if it is attainable without a great deal of extra expense. It is in the knowledge of the above points, and of the application of them in practice, that what may be called the science of