ANTISEPTIC TREATMENT OF WOOD. 509 



SECTION II. ANTISEPTIC TREATMENT OF WOOD. 



I. Methods for Converting the Decomposible Constituents 



of Wood into Antiseptics. 



According to Renews process at Stettin, the wood is dried 

 by hot air in a closed chamber; after the air has been 

 exhausted, oxygen is admitted into the chamber. The oxygen 

 that is absorbed by the wood is converted by intermittent 

 electric sparking into ozone, by means of which the readily 

 decornposible constituents in the wood are oxidised into 

 terpenes and creosotes. 



Haskins' process* consists in placing the wood in cylindrical 

 waggons into an iron boiler 6J feet in diameter and 112 feet 

 long (Fig. 309). After the boiler has been closed, air heated 

 to 300 to 500 C. is pumped into it for several hours, after 

 which the pressure is removed and the wood allowed to cool. 

 Owing to the high temperature, sugar, gum, tannin, protein 

 and starch are converted into the antiseptics, acetic acid, 

 methyl alcohol, phenol, creosote, etc. ; these substances 

 amount to 12 per cent, of the weight of the wood. The pro- 

 cess is termed Haskinisation, or Vulcanisation, and has given 

 good results on the Manhattan Railway, New York. 



II. Methods for Removing the Easily Decomposible, 

 Soluble Constituents of Wood, and replacing them 

 by an Antiseptic Substance. 



1. Materials used for Injection. 



A number of substances have been known for a long time 

 that render wood durable, such as resin, essential oils, 

 camphor, tannic acid, acetic acid, heavy tar-oil (creosote) ; 

 also several salts, as green, white and blue vitriol (sulphates 

 of iron, zinc, and copper), chlorides of iron, zinc, mercury or 

 magnesia, Glauber's salt (sodium-sulphate), common salt, etc. 

 Only a few of them are, however, applicable on a large scale, 



* According to Grady, " Rev. des Eaux et Forets," 1896, Mayer has the prior 

 claim to this invention. 



