2oS The Journal of Forestry. 



tured from the sappy or inferior part of the tree. . . . It is seldom 

 that wood that looks well to ev^ea an inexperienced eye turns out 

 badly. Were it not good, and likely to command a fair price, the foreign 

 merchant would not take such pains in its manufacture. A good colour 

 throughout, and square edges, imply tolerable freedom from sap and wane. 

 Knots and shakes speak for themselves." 



With reference to the process of preserving timber by creosoting, invented 

 by Mr. .John Bethell, of London, in 183C, and still carried on largely by 

 his firm and others, the author says, — " It consists in placing the timber 

 in a large cylinder, which is hermetically closed ; and in the first place, 

 exhausting the air from the cylinder, by which means much air and 

 moisture can be extracted from the pores of the wood; secondly, in 

 filling up the cylinder with creosote oil and pumping it by hydraulic 

 pressure into the timber till the latter has absorbed from eight to twelve 

 pounds of creosote per cubic foot. 



" Creosote is an oil of heavy gravity obtained from coal-tar, from which it 

 derives much naphthaline and crude carbolic acid, both powerful antiseptics. 



" The idea of impregnating timber with creosote was suggested to Mr 

 Bethell by the perfect preservation of Egyptian mummies embalmed in. 

 petroleum. The creosoting process (if conscientiously performed) appears 

 to respond to all the requirements of science, and to be likely to preserve 

 timber until it is worn out by mechanical action. It fills the woody cells, 

 and protects the fibres by an elastic india-rubber like substance, effectually 

 excluding air, moisture, and heat, the presence of all of which are required 

 in order for decay to begin, 



" After a few mouths creosoted wood gives a metallic sound when struck, 

 and is almost too hard for carpenters' tools to work upon, though, at the 

 same time, it possesses an elasticity superior to that of any but green- 

 heart tiinbcr unprepared. Creosoted wood completely resists the attacks 

 of all sea worms, insects, and white ants, and is almost universally re- 

 quired by engineers in places where these troublesome animalculas exist. 

 Its use has become general, with only one or two exceptions, on English 

 and Irish railways. A creosoted sleeper has been known to wear out three 

 or four sets of rails; whilst, in the case of uncreosoted sleepers, the rail 

 generally lasts the longer. 



'■ Creosoted timber is prescribed on the Belgian and Dutch State rail- 

 ways, even oak being creosoted. In Germany it is used on a very large 

 scale, even in districts where sleepers are most plentiful and cheap. In 

 France it divides the ground pretty equally with the sulphate of copper 

 process, which injects precisely in the same way a solution of the salt 

 5 per cent, strong." Her Majesty's post office authorities have all tele- 

 o-raph poles creosoted except larch, which is too resinous to permit of due 

 impregnation. The excellence of this process is generally recognized, and 

 the inventor has been awarded several international exhibition prize medals 

 in recognition of it. 



