522 



AUXILIARY FOREST INDUSTRIES. 



affect matters in this respect ; this question should be decided 

 experimentally. 



4. Jtcsiilt* of Injection. 



As regards the results of injecting railway-sleepers, it is 

 evident that the locality, nature of the soil and wear-and-tear 

 on a railway must be considered in judging their durability. 

 The method of injection, the anatomical structure of the wood 

 and whether the injected wood is used immediately after 

 injection or is first kept some time in store, also affect its 

 durability. 



As regards the methods of injection, the following are the 

 results given by experience on German Railways : 



Other investigations give the following data for the duration 



of railway-sleepers : 



Species. 



Beech, not injected 



with zinc chloride 



,, creosote 

 Oak, not injected . 



,, zinc chloride . 



,, creosote 

 Scots pine, not injected . 



,, ,, zinc chloride 



,, ,, creosote 



/// Elsass-Lothringen. 

 Oak, not injected . . . 21 

 creosote ... 21 



Beech, creosote .... 21 



52 



26-8 

 6-4 



