568 INDUSTRIAL USES OF WOOD. 



no durability. Pines suitable for water-pipes are free from 

 knots, with fine bark and small crowns. Trees 10 inches to 

 16 inches in diameter, chest high, are the best. As larch has 

 very little sapwood any straight tree of sufficient size will 

 serve the purpose. Usually these woods last 8 years to 10 

 years if they are laid at a proper depth below the surface 

 of the soil, somewhat over 2 feet, where frost and heat do not 

 affect them. 



Failing these, woods of spruce, silver-fir and alder may be 

 used. Oakwood gives the water a bad taste, it is too expen- 

 sive for the purpose, and other woods are not sufficiently 

 durable. [Deodar- wood is the best to use for aqueducts in the 

 Himalayas. Tr.] The wood is bored and used quite green, 

 and supplies of wooden pipes must be kept in running water 

 to prevent warping and cracking. It is preferable to keep 

 them in dry sheds than in stagnant water, where spores of 

 fungi get into the tubes and cause premature decay. 



Single pipes are 10 feet to 13 feet long, as it is difficult 

 to bore them to a greater length. The wall is generally as 

 thick as the bore. 



3. Wood used for Timber Export- Works. 



Wood is used frequently in forest export-roads, slides, or 

 sledge-roads. Wherever there are extensive coniferous forests, 

 and the local prices of wood are low, large quantities of wood 

 are used for fencing, supporting embankments, culverts, bridges, 

 and for covering swampy ground ; all kinds of wood, chiefly 

 coniferous wood, are used. 



4. Wood-Paving.* 



Wood-paving is now employed in the streets of large cities. 

 [In London, jarrah (Eucalyptus marginata) and kari (E. 

 diversicolor) are used largely for this purpose, and doubtless 

 Pyngado (Xylia dolabriformis), and other heavy Indian woods 

 might be used with advantage. Tr.] Among European 

 species the hardwoods, beech, oak and elm are best, but owing 



* C. L. Hill, "Woo<l-i>avin- in the United States,' U.S. Dep. of Agri., 

 March 1, inos. 



