•19± JProcesses for Wood-preser cation. 



769. The Bethell Process was patented by Mr. John Bethell, in 

 England, July 11, 1838. It consists in subjecting seasoned timber, 

 under pressure, to creosote or oil of tar and other bituminous sub- 

 stances that contain it, and also to pyrolignite of iron, which holds 

 more creosote in solution than any other watery menstruum. While it 

 unquestiouablyrenderswoodmuchmoredurable,andalso proof against 

 the attack of worms in sea-water, it has the disadvantage of ren- 

 dering it more combustible, and of offensive odor. We have known 

 a bridge frame set on fire and consumed while under construction, 

 by a workman attempting to burn out a hole through two pieces in 

 contact, so as to allow a bolt to fit. 



770. Creosote coagulates the albumen, fills the pores of timber ■ 

 with a bituminous substance, prevents the absorption of water, and is 

 obnoxious to animal life. By a patent of 1853, Bethell proposed to 

 first inject timbers with metallic salts, and after thorough drying, 

 inject creosote. He used about 10 pounds of creosote to a cubic 

 foot. It is sometimes carried to twice this amount. It has been 

 most used on pines, and for railway ties, and enormous quantities of 

 the latter have been sent to India and other hot climates. It is 

 also largely used for piles, docks, and bridge timbers. 



771. The pressure employed varies from 150 to 200 pounds to 

 the inch, and the liquid is heated to 120° (Fahr.),. and admitted 

 after the air has been exhausted. The cost varies widely, but aver- 

 ages perhaps 7 to 8 cents a cubic foot. Eailway ties that are half- 

 round last longer when thus prepared than those that are sawn 

 square, and a fine open sand is best for ballast. It is found that 

 ties that have been creosoted are stronger and better able to resist a 

 crushing weight than before, but sometimes in India they have suf- 

 fered from the white ants. 



772. The Boueherie Frozess. In December, 1837, Dr. Auguste 

 Boucherie, of Bordeaux, France, proposed the injection of antise{>tic 

 fluids through the natural circulation of the living tree. He suc- 

 ceeded in the use of the sulphates and the acetates of copper, of 

 iron, and of zinc, the bi-chloride of mercury, a':«enious acid, aud 

 the arseniate of potash, and in some cases of several of these in 

 succession. Of odorous substances, he procured the absorption of 



was recommended by Strutzlsi in 183+, Earle in 1843, and Apelt in 1853. 

 Bohl . . . has etuployed it simultaneously with creosote." 



