190 



ENGINEERING ON THE FARM 



BlASTfNG CAP 

 /V7UD^ V FUSE 



OYA/AM/TE. 



After E. I. du Pont de Nemours & Co. 



Fig. 171. Breaking bowlder by mud-capping 



^ 



DYNAM/TE Pft/MEft 



^Sl/T CAPTR/OGES 

 PRESSED T/GHT / 



After E. I. du Pont de Nemours & Co. 



Fig. 172. Breaking bowlder by snake-holing 



these three methods depend upon the hardness and solidity 

 of the rock and upon the relation between the cost of labor 

 and the cost of the explosive. Mud-capping (Fig. 171) 



