330 LAND-TRANSPORT. 



(c) Wet Slides. — The description of slides will be completed 

 by an account of wet slides, which must be made as nearly 

 water-ti<,'ht as possible, so as to hold a moderate stream of water, 

 and must therefore be much more carefully constructed than 

 dry-slides. 



As fi<i. 174 shows, they are ^^enerally made with ei^dit hewn 



poles, the sides of which lit closely, and the iutcrstices are 

 stopped with moss, or with tarred tow, itc. 



[A wet slide in the Deota Forest in 'Piliri-lJarliwal in the X. W. 

 Himalayas, was constructed in 1876-78 being 12,192 feet long with 

 a fall of 1,300 feet, the gradients 5-22 degrees, and the best gradient 

 15 degrees. It consists of a trough composed of three planks 

 (12 feet X 13 inches x 5 inches) roughly joined and firmly wedged 

 into block-sleepers. Being made of Pitms lonf/ifolia, the latter 

 only last 3 or 4 years, but should be made of deodar- wood, which 

 is very durable in the hill-districts of India. The slide is worked 

 by means of a good flow of water which is sujiplied by troughs at 

 intervals of about a quarter of a mile, a good depth of water 

 being required when the gradient is less than 18 degrees. When 

 there is plenty of water, 1,200 railway-sleepers can be passed 

 down in about 10 hours, each sleeper taking ten minutes on its 

 journey. (FtWf fig. 176.) 



An account of this slide is given in the workingi)lan* of the Tihri- 

 Garhwal Forests. — Th.] 



For short wet slides, where there is a plentiful supply of 

 water, preference should be given in tiicir construction to merely 

 hewn poles, instead of planks, as repairs are thus facilitated. 



• liy N. Ilcarlf, i.ulili.slied :it Ailulial.ail, for tlu' Government of the N. W. 

 I'roviiiees, 18S8. 



