.S.| 



ENGINEERING <>N THE FARM 



Firing the charge. Before an attempt is made to light 

 a safety fuse, a split, of three quarters of an inch should be 

 made with a knife and the match held in such a way that 



5 4 



\ttiT K. 1. <lu Pont ilo NiMuour.s A Co. 



Pig. k>|. Two-post blasting machine 



i Rack bar i Shunt spring s Platinum bearings 8 Principal magnet 

 i. Commutator h> -Armature .; i Handlebar 



the blaze strikes the freshly exposed powder. At the time 

 the fuse is lighted it should be watched until there is a cer- 

 tainty that the powder core is burning. This may be ascer- 

 tained by the smoke, the hissing sound, or the melting of the 

 waterproof wrapping. Persons unaccustomed to the use 

 o( a fuse should Tamilian e themselves with it by burning 

 several short sections before undertaking to fire a charge. 

 For electric tiring a blasting machine is used, which is 

 simply a small magneto incased in wood (Fig. 164). These 

 machines differ in strength, the smallest one tiring eight caps 

 ai a time on one circuit. Insulated wire extends from the 

 maehine to the charge, being oi sufficient length to enable 

 the operator to stand at a place of safety at the time o( tiring. 



