450 THE HANDBOOK FOR PRACTICAL FARMERS 



is placed is for the purpose of more closely confining the charge 

 to insure better work and is called ''tamping." It should be 

 made as tight as possible so that the gases will not blow out as 

 through the muzzle of a gun. 



To guard against danger of prematurely detonating the 

 charge, the first five to eight inches of tamping should not be 

 packed with any considerable force, but should be gently firmed. 

 When this amount of lightly tamped material covers the primer, 

 the rest of the tamping should be made as hard as possible, using 

 the wooden tamping stick in one hand. 



Moist clay, free from gravel and clods, makes good tamping 

 material. Free running sand or moist loam is also good. In wet 

 work, when a foot or more of water covers the charge in shallow 

 holes, it will not be necessary to add other tamping, as the water 

 will hold the charge sufficiently tight. Loading and tamping 

 should be done in such a way that no open-air spaces are left. 



When using soil for tamping, the hole should be tamped full. 

 Do not allow sharp pebbles or stones to fall in the hole during 

 loading and tamping. 



Before beginning tamping, it is well to measure the depth 

 from the surface to the top of the charge so that if the tamping 

 must be removed to get at a misfire, there will be no danger of 

 disturbing the primer. It is a good practice, especially where 

 heavy charges are used, to place two inches of paper or dry 

 leaves immediately over the primer, so that they can be used as 

 a safety marker should the tamping need to be removed for any 

 cause. 



Firing. — Exploding the charge is called "firing," and can be 

 done either by means of caps and fuse or by electric blasting 

 caps with a blasting machine. When cap and fuse are used, cut 

 the fuse long enough to reach about three inches out of the bore 

 hole and to enable you to retire to a safe distance. Fuse burns 

 on an average of two feet per minute and a sufficient length 

 should be used to permit of the blaster reaching a safe point 

 before the explosion. When using electric blasting caps, the 

 leading wire should be long enough to enable the one who oper- 

 ates the blasting machine to be outside the danger zone. No 

 blast should be fired until persons, animals and vehicles are well 

 out of range. 



When reliable explosives and blasting supplies are used, and 

 the primers properly made and placed, misfires should seldom 

 occur. When using cap and fuse, and a misfire is noted, do not 

 return to examine it at once, as an injured fuse may be burning 



