PLAME-RESISTING WOOD— STORAGE 75 



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 durabiHty of timber. 



Flame-resisting wood. — In connection with building, and still 

 more with railway roHing-stock, it is important that wood, though 

 it can hardly be made absolutely fire-proof, should be rendered so 

 fire-resisting that it wiU only smoulder and not burst into flame. 

 Several substances have been injected for this purpose, and others 

 have been used as surface paints. Of the former, the more im- 

 portant are sodium tungstate, ammonium sulphate with boric 

 acid, and ammonium phosphate, the last-mentioned being the 

 most efficacious, but requiring to be injected under a high pres- 

 sure. Of the paints, asbestos and soluble glass are, perhaps, the 

 best. 



Storage. — ^Por 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 sHghtly lower than 

 their tops, if every log or scantHng be so separated by smaU 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 acces- 

 sible. 



