306 WOOD TRANSPORT BY LAND. 



Where roads cross shifting sands they may be constructed 

 similarly. 



ii. Corduroy-roads. 



These are made under similar circumstances to the 

 fascine roads for crossing short stretches of swampy ground. 

 In this case, the lowest layer consists 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 above 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 hollows in the construction of sledge-roads. 



iii. Sledge-roads 



Permanent sledge-roads are used in the summer transport 

 of wood over slightly sloping ground. In order to reduce 

 friction in sledging logs or fire- wood, the road is laid trans- 

 versely with middle-sized round billets which are held in 

 position by pegs driven into the ground. Their distance 

 apart should not exceed two feet, so that the sledges may 

 rest always 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 Barr forest-range in Alsace, sledge-roads are exten- 

 sively used, also in most of the forests of the Vosges 

 mountains. 



[A much more elaborate sledge-road than those described 

 here was made in the forest of Tihri Garhwal, in the 

 north-west Himalayas.* Its gradient varied between 5 and 

 11 degrees, and experience shows that 8 degrees is best, and 

 the sharpest curve has a radius of 20 feet. The length of this 

 sledge-road is 5877 feet, and the total fall 835 feet. It was 



* For :i complete ncroim! of Ihisslcd^c-roml, sec ' Indian Forester," Vol. XII. 

 p. .",r,<;. 



