WOOD. 353 



What is the 888. EFFECT OF MURIATIC ACID. This 



acid aci ^ has no very strik i n g effect on wood 



on wood? or other organic substances. But chlorine 

 decomposes and destroys them ; principally, in conse- 

 quence of its affinity for hydrogen, as before explained. 



What effect ^89. EFFECT OF ALKALIES. - Alkalies 



have alkalies have the effect of hastening the decompo- 



on wood and . . 



similar sub- sition of organic substances. This effect 

 is, in part, due to the fact that they promote 

 the absorption of oxygen from the air. Paper or cloth 

 in contact with lime or potash, is found to lose its 

 strength speedily, and finally to crumble away. The 

 theory of this action has already been given in the 

 paragraph on nitrate of lime. Where the atmosphere 

 is excluded, it would seem, from certain experiments, 

 that lime has an opposite effect, and rather retards than 

 promotes the decomposition of organic matter. 

 What differ- 890. W OD VINEGAR. The acid pro- 



cnt substances duct, as obtained in the dry distillation 



are contained . , . , . . , , 



in wood vine- of wood, contains, beside acetic acid and 

 gar? water, a sort of alcohol, called wood- 



spirit, and an oily, colorless fluid called kreosote. The 

 latter has the odor of smoke, and has the same 

 effect in preventing the putrefaction of animal sub- 

 stances. The effect of smoke is owing, indeed, to the 

 kreosote which it contains. A dilute solution of this 

 oil in water, is used in medicine and for curing meats. 

 891. WOOD TAR. Wood tar is a mix- 

 cl?are Sl con an ' ture of various oils, and volatile crystalline 

 tained in wood solids composed principally of carbon and 

 hydrogen. Kreosote, which is also ob- 



