342 Forestry Quarterly. 



greater, but after seven years the financial effect would be in their 

 favor. 



The author explains his conception as to the reason why creo- 

 soted poles last longer. A cubic meter of wood is treated with 5 

 kilogram sulphate of copper, or else with 150 to 200 kilogram 

 creosote. The latter contain at least 8 per cent pheriols, the pre- 

 servative element, hence there are 12 Kg. in the wood, or more 

 than twice the quantity of preservative, which, moreover, may in 

 itself be more effective. In addition, the oiliness of the creosote — 

 objectionable to the repair men — keeps moisture away as long as 

 the soil is not evaporated. Temperature will do this, while the 

 copperas is merely leeched out. 



Only wood of resistent species should be used, since even with 

 the best impregnation the individual character of the wood has a 

 bearing on its durability. 



Ueber ien Wert der Impraegnierung der Telepraphen-Statigen, 

 AUgemeine Forst- und Jadgzeitung, Sept., 1906. Pp. 301-304. 



Recent Experiments by Hornberger and 



Combustibility Selheim at the Miinden Poorest Academy on 



of the combustibility of oak and beech wood 



Wood. have sTiown that the two are in this respect 



practically the same. Oak burns through 



slower than beech when it is of vigorous growth and heavy. Light 



wood grown on poor sites burns more rapidly than beech. Beech 



shows less variation in the tests in question than oak. Since it is 



not possible to distinguish between the different grades of oak in 



specifying for building purposes, it is purposeless to exclude beech 



where it is thus shown to be better than certain grades of oak which 



are not excluded. 



Looking more closely into some of the comparative tables we note 

 that in one test oak burned through in one-fifth longer time than 

 beech and the extent of charring was one-third more on the beech. 

 On exposing similar sticks to a certain heat, the oak broke into flame 

 in two minutes and sixteen seconds, the beech in two twenty-six. 

 On the whole, charring was about as extensive on the one as on the 

 other and elaborate statistical methods are necessary to bring out 



