272 MASSACHUSETTS AGRICULTURE. 



lias been tried in this country now for ten years, bids fair to 

 largely supersede the stone blocks. It meets one great desider- 

 atum, among others, of furnishing a less noisy, and more elastic 

 surface than stone. 



But most of the roads of the State must be built of loam, 

 clay, gravel, and sand, more or less mixed, and with these ma- 

 terials we must do the best we can. 



A road-bed of clay is good in dry weather, and one of sand is 

 tolerable in a wet time, and the latter is but slightly affected by 

 the frost, but we need one which will be good at all seasons. 



Not being able to make the surface " water tight," there must 

 be a substratum that will carry the water from above, and that 

 from below, as quickly as possible to the drains. Whatever may 

 be used for this under layer, pebbles greater than one inch di- 

 ameter should not be placed within ten inches of the surface, for 

 otherwise, when there is a compact foundation, they are sure to 

 work up, from the downward pressure of gravel, forcing itself 

 beneath them. Clean gravel, rejecting stones above an inch 

 diameter, put on in successive layers of three or four inches, to 

 the depth of ten inches, each layer being well worked down 

 with a heavy roller, assisted by the daily travel, with a small 

 admixture of finer gravel or loam upon the top, in some cases 

 will make as "good a surface as we can expect for the majority of 

 our best roads. 



Pebbles, about an inch in diameter to two or three inches, 

 placed upon the surface, will not pack together, on account of 

 their hardness and smooth, round surface. It is well under- 

 stood that McAdam and Telford roads are made of broken stone 

 — angular fragments. 



A pure sand road is improved by a topping of clay or loam ; 

 and it may be six inches in thickness, or more, according to the 

 depth of the sand. 



Quite passable roads have been made in a region where a 

 vegetable mould and loam lay upon pure clay, and no sand or 

 gravel was at hand, by leaving the surface as nearly as possible 

 in its natural state, and flanking with deep ditches, throwing 

 the excavation from them out, and not upon the road-bed. 



A very good use of stones, if they are abundant, is to place 

 them in a slough that must be crossed. But if it is deep, a 

 better method is to use poles or brush, in alternate layers, first 



