."314 LAND-TRANSPORT. 



is laid, and the surface is completed with ^a-avel, iron-pan 

 or clay. Sand alone should not be used, as it soon finds its 

 way through the substructure of the road, and in any case is a 

 bad binding material ; sand, however, when mixed with clay or 

 loam, may be used to cover the roadway. 



Where roads cross shifting sands they may be similarly 

 constructed. 



ii. Ilodils made with lloiind or Sj^Ut Billets. 



These are also made under similar circumstances to the fascine 

 roads for crossing short stretches of swampy ground. In this 

 case, the lowest layer should consist of middle-sized logs placed 

 close together longitudinally in the direction of the road, and 

 upon them round or split billets of wood are packed transversely, 

 whilst poles are pegged-down firmly on both sides along the 

 edges of the roadway abos'e the billets to retain them in position. 



This kind of road is used to prevent the feet of beasts of 

 draught from sinking into swamps, and is also much used for 

 filling-up hollows in the construction of sledge-roads. 



iii. Sledge-roads. 



Permanent sledge-roads are used in the summer transport of 

 wH)od over slightly sloping ground. In order to reduce friction in 

 sledging logs or fire-wood, the road is laid transversely with 

 middle-sized round billets which are held in position w^ith pegs 

 driven into the ground. Their distance apart should not exceed 

 two feet, so that the sledges may always rest on at least two of 

 them. To reduce friction further, the billets are often smeared 

 with grease, or water is poured on them. In the case of their 

 being too slippery after rain, sand may be strewn on them to 

 increase the friction. 



In the ]3arr forest-range in Alsace, sledge-roads are extensively 

 used, also in most of the forests of the Vosges mountains. 



[A much more elaborate slcdge-road than tliose described here has 

 been made in the forest of Tihri (Jarlnval, in the north-west Himalayas*. 

 Its gradient varied between o and 1 1 degrees, and experience shows 

 that 8 degrees is best, and the sliarj)cst curve has a radius of 20 feet. 



* For a coniplute account of tliis sletlgc-road, see Indian Forester, Vol. XII., 

 p. 366. 



