118 IXDUSITJAL USES OF M'OOD. 



the hardwoods, beech, oak, and ehii are best, but owing to its 

 cheapness Scotch pinewood is also hirgely used, and bus proved 

 to be as durable for this purpose as Pitch pine. 



Injected wood is generally used, and zinc-chloride is said 

 to have given better results in this respect than creosote. 

 The wood is used either in rhombs, or rectangular prisms, 

 placed on a slightly arched dry layer of concrete, molten asphalt 

 being poured between the blocks, which are afterwards covered 

 with a layer of fine gravel and well rolled. 



Wooden street-paving has proved as durable as asphalt, and 

 does not exercise so much wear and tear on the shoes of horses. 



Fig. .32. 



or the tyres of vehicles ; it also affords a firmer foothold to the 

 horses, and makes less noise than stone-paving. The blocks of 

 wood are 6 — 12 inches long, 8 inches broad and G — 7 inches 

 thick ; when rectangular they are placed endways, and when 

 rhombic, as in the figure. Blocks of Scotch (red) pine and other 

 wood are also used for the flooring of stables, threshing-floors, or 

 outdoor staircases. 



5. Uailiraji-Sleejx'rs. 



Up to the present time railways have made great demands on 

 forests, chiefly for railway-sleepers, or ties, as they are termed in 

 America. 



[The dimensions of railway-sleepers vary in different countries, in 

 England being 9 feet x 10 inches x 5 inches, or 3| cubic feet ; 

 eleven of these sleepers are used for 30 feet of line, being about 

 2| feet apart, but are further apart towards the centre of the rails and 

 closer near the joints. Each i-cd juno slee})er is saturated with 

 2 J gallons of creosote, which is forced into the sleepers under 

 pressure. The breadth of gauge between the rails is 4 feet 8i 



