1912.] 



Preservation of Timber. 



of the original weight, but in the case of yellow pine of the 

 western United States as much as 49 per cent, was lost during 

 seasoning in from three to nine months. 



The rate at which wood seasons was found to depend 

 chiefly on climatic conditions, timber cut during spring and 

 summer becoming seasoned, as a rule, much more rapidly 

 than that cut in autumn or winter. Soaking the timber in 

 water, the degree of exposure to the air, and the method of 

 piling the timber also affect the rate of seasoning. Timber 

 which is seasoned rapidly is much more liable to split than 

 that which is seasoned more slowly. In the latter case 

 numerous small splits are formed, but these close again when 

 the wood absorbs moisture, and apparently no detrimental 

 effect is caused. If, however, the wood seasons rapidly, wide 

 and deep splits may be formed, which do not again close, and 

 which not only decrease the strength of the timber, but 

 materially hasten decay by allowing the entrance of insects 

 and fungi. 



Application of Preservative with a Brush. — A very simple 

 method of using a preservative is to apply it to the surface 

 of the wood with a brush, but while experiments carried 

 out in this direction by the Forest Service have given 

 good results, this form of treatment does not present a com- 

 plete solution to the question of timber preservation. It is 

 especially useful, however, where the erection of even the 

 simplest plant would not be justified, as the cost is very low. 

 Creosote was applied hot to poles of chestnut, cedar, and 

 pine, and the average amount of preservative absorbed in 

 each case is shown in the following table : — 



Species. 



Absorption per Pole. 



Length and 

 Diameter 

 of Pole. 



Length 

 Treated. 



Chestnut 



White cedar (Southern U.S.) 



„ (Northern U.S.) 

 Red „ (Western U.S.) 

 Yellow pine ( „ ) 



lb. 



2-6 



2-4 



lb. 



47 

 4'9 

 4*4 

 6-5 



3'6 



ft. in 

 30 x 7 

 30x7 

 30 x 7 

 40 x S 

 40 x 8 



ft. 



6* 

 6* 

 6" 

 St 

 7t 



* Between 2 ft. and 8 feet from butt end. 

 t From butt end to height indicated. 



