USE OF EXPLOSIVES ON THE FAEM 449 



disadvantage of a slight increase in size. This method is the one 

 generally used by agricultural blasters. 



Cutting a dynamite cartridge in half. — When small charges 

 are desired, it becomes necessary to cut cartridges in half. This 

 should be done with a sharp knife. Hold the cartridge firmly 

 in one hand and the knife in the other. Giving the cartridge a 

 rotary motion, cut the paper all the way around and then bend 

 the cartridge slightly, when it will come apart just where the 

 paper is cut. Never try to cut a frozen cartridge. 



Making hore holes. — The holes made for loading explosives 

 are called ''bore holes." These should be prepared before the 

 primers are made. The tools required for making such holes 

 are few and simple, consisting either of a sledge and pointed 

 steel bar or of soil augers. Bore holes in rock, of course, have 

 to be made with rock drills. 



Loading. — When the cartridge is primed and the bore hole 

 made, the next thing to do is to load. First try the hole with 

 the tamping stick to see that it is open and will permit the charge 

 being placed at the desired point. 



When loading small charges, as when only a full or half car- 

 tridge primer is used for subsoiling or tree planting, start the 

 primed cartridge into the bore hole and press it gently into place 

 with the tamping stick. See that it is firmly seated in the bottom 

 of the bore hole. 



In pressing a primer into place, do not handle it roughly, as 

 it contains the cap and is, therefore, more sensitive and danger- 

 ous than an unprimed cartridge. 



When the load is to contain a larger amount of dynamite, 

 press the unprimed cartridges into place in the bottom of the 

 hole first, and place the primer with the cap pointed toward the 

 rest of the charge on top. When the bore hole is dry, and it is 

 desirable to have the charge concentrated in one place, it is a 

 good practice to slit the sides of the cartridges in two or three 

 places and from end to end with a knife so that the dynamite 

 can be compacted into a smaller space. The primer should not 

 be split. 



In all classes of agricultural blasting, the charge should be 

 pressed firmly into the bottom of the bore hole so that no air 

 pockets are left, as they weaken the action of the explosives. 

 When bore holes are wet, it is not advisable to slit cartridges. 



For most work it is necessary to determine the correct amount 

 of explosives by a few test shots. 



Tamping. — Closing the top of the bore hole after the charge 



