88 OF WOOD IN GENERAL. 



surface of the bath, the aseptic borax and resin solution replacing 

 it in the pores of the wood. Artificial drying, or a fortnight's 

 natural seasoning in summer weather, will then complete the 

 process. 



Such impregnation-methods double or treble the life of railway 

 sleepers. On the other hand, it should be remembered that paint 

 prevents not only the entrance of moisture, but also its exit ; so 

 that if applied to imperfectly seasoned wood it merely protects 

 the dry rot which finds a sufficiency of moisture in the wood. 

 Even perfectly seasoned wood, if not protected by tar or paint, 

 requires good ventilation if it is to last. Warm, moist, stagnant 

 air or draught, and partial contact with moist earth or water are 

 the most unfavourable conditions for the durability of timber. 

 A process has recently been introduced for rendering wood "non- 

 flammable" by extracting the resin and volatile matter under 

 hydraulic action and then injecting chemicals. This process is 

 applicable to wood up to 6 inches in thickness and to hard woods 

 as well as soft woods, and dries them effectually at the same time, 

 so that there is no subsequent change of form ; but it adds about 

 25 per cent, to the cost of soft woods and more to that of hard 

 woods. It has been largely used in the United States navy. 



Storage. For the storage of seasoned timber much the same 

 precautions are requisite as for that which is undergoing air- 

 seasoning, viz. thorough ventilation, absence of contact with 

 moist earth, and preferably some protection from rain and sun. 

 If logs are stacked with their butt-ends outward and slightly 

 lower than their tops, if every log or scantling be so separated by 

 small packing billets that it can be removed without disturbing 

 the remainder, and if each tier of timber is set back a few inches 

 so as to obviate the use of a ladder, it will render the stock not 

 only safe but accessible. 



