250 



FELLING AND CONVERSION OF TIMBER. 



iii. Blasting Stumps by Dynamite. 



Dynamite is a more powerful explosive than gunpowder, and 

 is obtainable in cartridges resembling brown stearine candles 

 encased in thick paper. It becomes hard at temperatures of 

 45 to 50 Fah. and cannot be heated above 108 Fah. without 

 danger. It will not explode unless it be at least as soft as 

 wax, and must therefore be warmed slightly during winter. 



According to the size of the stump 

 1-72 grams (1 1-12 drams) of 

 If dynamite are required for every centi- 



meter in the diameter of the stump, 

 so that cartridges of 70 to 100 grams 

 suffice for stumps of 0'50 to 0*70 

 meters in diameter [i.e., 2| to 3J 

 ounces for diameters of 1 foot 8 inches 

 to 2 feet 3 inches. Tr.] , provided the 

 wood is not too difficult to split. 



The dynamite-cartridge (p) in Fig. 

 157, is then placed in the bore-hole, 

 which should be of suitable bore to 

 admit it, and rammed home with a 

 wooden ram-rod. A smaller cart- 

 ridge (z) is used in connection with 

 a fuse for firing the charge, the end 

 of the fuse being placed on the soft 

 mass of dynamite of this cartridge, 

 and tied firmly above it in the paper 

 covering of the latter. This firing- 

 cartridge and fuse is then let down on to the blasting-cartridge 

 in the bore-hole. The vacant space in the bore-hole is then 

 tamped with earth and the fuse lighted. 



Whilst blasting with powder frequently only cracks the stump, 

 by the use of dynamite it may be torn into several pieces. 



As regards the cost and saving of labour by blasting the 

 stump, various estimates representing from 30 to 50 per cent, 

 labour saved have been made ; for oak-stumps the cost is 

 estimated at 6d. per stacked cubic meter cheaper than manual 

 labour, and for Scots pine at 3d. more. 



Fig. 157. Blasting with 

 dynamite, c Fuse. 



