Page:Remarks on the Present System of Road Making (1823).djvu/215

 *table soil, so as to cut off all connexion with clay. Where gravel is the material to complete the road with, I have already mentioned, that it ought to be completely cleansed of every particle of clay or earthy substance, and its different sizes ought to be selected and arranged by means of riddling or washing; in the use of the riddle, the particles of earth or clay adhere so much to the stones that it frequently requires to be exposed to the sun, air, and frost, for several months, and then riddled over again. In this gravel, the stones are of different sizes and different shapes; all those that are round ought to he broken with a small hammer, and in mentioning hammers, I beg leave to draw the attention of the Committee to their weight, shape and manner of using, which is of much more importance than any one can conceive who has not had much experience in road-making; the difference in managing this operation being not less than ten per cent. and is, besides, of equal importance towards the perfection of the road; the size and weight of the hammer I would apportion to the size and weight of the stones, and the stones should be broken upon the heap, not on the ground; it must be evident that using round stones will be the means of deranging the position of those near them, and of grinding them to pieces.

Are you of opinion that the gravel which is found in the pits in the neighbourhood of London is calculated for making roads capable of bearing the heavy weights which the great traffic round London occasions to be used upon them?—I am of opinion that the materials in the whole valley or plain around London being entirely silecious, or flints, and easily ground, to dust, are very improper. This must be evident to every person who travels near London in any direction.

Are you of opinion that it would be advisable or practicable