THE FARM H0L1UM.. 1 13 



dirt and compressed air straight m front. No tamping of any kind is to be 

 used in this operation, as it is not necessary. After tho explosion, push the 

 tamping stick down into the " bull " to make sure everything is clear, before 

 putting the final charge in; if necessary, clean out the hole with the earth 

 auger and proceed to drop the charge in, one plug at a time, pushing each 

 plug down into the "bull" chamber with the tamping stick; lastly the 

 primer — the plug with the detonator and sufficient length of fuse attached — 

 is put in gently and pressed home. Now get a wad of paper — any sort will 

 do — and make a ball about the size of a fist; hold the fuse firmly in place 

 with one hand, and press this paper wad down into the hole to a depth of 

 about 3 feet, or two-thirds of the depth of tho hole, taking care that the 

 primer is not drawn out from contact with the rest of the charge, while holding 

 the fuse. Having fixed the paper wad firmly, drop in a few handful- of 

 loose moist earth; tamp this very gently until it is firm and solid, and is 

 not moving the paper in the hole; then add more earth and tamp it until 

 the remainder of the hole is full of well-tamped earth. To facilitate the 

 lighting of the fuse, cut a diagonal snick in the top end, right into the powder 

 core, and into this insert a small wedge-shaped piece of gelignite ; this ignites 

 quickly when the match is applied and is not easily blown out by the wind 

 The reason for using the paper wad when tamping is that ample air space 

 may be left in the region of the explosion ; the effect of such an air chamber 

 is to slow down markedly the rapidity of the action of the gelignite when it 

 explodes — an effect that is of importance, both in regard to the wider area 

 covered by the explosion and also the more economic use of gelignite. It 

 is not advocated as a general thing that green or growing trees should be blown 

 out, because of the sweetening of the soil that goes on in a more definite way 

 while timber is dying than if green timber is removed at once. The increased 

 cost due to live trees having a much stronger hold and consequently requiring 

 more explosives must also be considered. It sometimes happens, however, 

 that it is necessary, or at least advisable, to remove green timber. In such 

 cases better results can probably be obtained by firing the charge electrically, 

 putting down three or four holes, so placed round the tree as to do the lifting 

 where the rooting indicates it to be necessary. In this case all the holes 

 should be about 4 feet deep and " bulled," and the same precautions as to 

 tamping and using the paper wad should be adopted, as previously described ; 

 then after connecting up the wires of the various charges " in series," round 

 the tree, leaving one wire from the first and last charge to be connected to 

 the twin wire firing cable, lay this firing cable in the direction of the sun, so 

 that when the operator comes to exploding the charges with the battery, he 

 will be facing the tree with the sun at his back. Should the explosion throw 

 pieces of timber or stones in that direction, he then will have a clear vision 

 and no glaring sun in his eyes to interfere with him in any movement that 

 may be necessary to avoid injury. The cable is 100 yards long, and it is 

 advisable to use the full length and to get right out in the open if possible. 

 The practice of getting behind a near-by tree shoidd not be encouraged, as 

 it may happen that a flying piece of timber may be hurled into the branches 

 of the tree and may be diverted sufficiently to fall upon someone there, or it 

 may strike a dead limb overhead and bring it rattling down. Being well 

 out in tho open offers many advantages as to safety. 



.After firing the charges, disconnect the cable ends from the battery ter- 

 minals at once, and twist them together ; take the galvanometer to the tree 

 just blown out and pick up the other two ends of the cable and by placing one 



