84 Farm Roads on Strong Soils. 



suitable stone or gravel was to be got in the locality, the lias 

 clay was burnt into ballast and used for the lower stratum or 

 foundation at a cost of 2^. Qd. per cubic yard, while the upper 

 stratum or covering was of Trent- gravel, and cost 85. per cubic 

 yard. 



Now it is easy to understand by a comparison of these figures 

 that in the first case sound economy was best promoted by 

 putting on an extra depth of material, whereby the cost of future 

 maintenance would be reduced to a minimum, whereas in the 

 second case, it was equally discreet to limit the expenditure 

 in covering-material to an amount just sufficient to make a hard 

 road, but which would oblige the tenant to observe considerable 

 watchfulness, and to expend annually an appreciable sum to 

 maintain it in good condition. 



In road-making, as already premised, certain fixed rules or 

 principles of formation or construction should be observed in all 

 localities, and these it is intended to particularize in the remarks 

 about to be offered under the head of "■ Fundamerital PrincijAesy 

 Those modifications which are due to different localities and 

 soils will be subsequently explained under the head of " Local 

 Modifications,^^ but they apply simply to the description and 

 quantity of materials used, and do not affect the primary rules 

 of formation. 



Fundamental Principles. 



So many circumstances are generally found to exist in a farm 

 which serve to predetermine the course of a required road 

 through it, that it would answer no useful purpose to expatiate 

 at any length on the longitudinal formation or section of roads. 

 The nearer all roads approach to a straight and level line the 

 lietter. A straight line, however, unless it be associated with a 

 level profile may easily lose the advantage of being the shortest 

 distance between two points. Mr. Macneill's experiments on 

 draught show that the actual saving in power by the adoption of 

 a course of road with inclinations of 1 in 40 is 20 per cent, over 

 one Avith inclinations of 1 in 20, all other considerations being 

 equal ; and these figures, when reduced to money value, show 

 that if the cost of carrying a ton of manure or corn along a road 

 with inclinations of 1 in 40 is 8(/., the cost of carrying the same 

 load along a road with inclinations of 1 in 20 is 10^. 



Tlie difference of 2rf. per ton in the resistance thus arising from 

 gravity alone, swells into a considerable item when multiplied by 

 the numerous tons of corn, straw, hay, and manure, of which the 

 internal traffic of a farm consists, and it sufficiently shows the 

 advantage of adopting gradients as flat as circumstances will 

 permit in all roads not necessarily fixed by the situation of the 



