Instead of using great lengths of these fuses, they may be cut shorter and their ends be brought together and inserted in a little mealed powder which is fired by a piece of safety-fuse, slow match or port-fire, etc., long enough to give the miner time to retire to a safe distance after igniting it. Bickford fuse is best ignited by a piece of cotton wicking soaked in oil and loosely tied around it. This, when lighted, will burn through the covering and set fire to the composition. By this device many fuses may be ignited in a short time. A slow match or “touch-paper” for igniting quick-burning fuses or powder-trains may be made by soaking common paper in a strong solution of nitre and drying it. CAMOUFLETS BY BORING. =74.= In favorable soil a camouflet or small mine may sometimes be placed and fired very quickly by the following process: A hole 2" to 3" in diameter and of the desired depth is bored in the proper direction with an auger or boring-bar. A cartridge containing from ½ lb. to 2 lbs. of dynamite is pushed down to the bottom and fired. The explosion increases the diameter of the hole somewhat throughout, and obstructs it more or less with loose earth. At the same time it enlarges the part near the seat of the charge into a bottle-shaped cavity, whose size varies with the charge used and the nature of the soil. The hole is rapidly cleared out with a long-handled scoop, the cavity filled with powder, primed, and fired. The enlargement made by the charges of dynamite above given may contain from 50 to 100 lbs. of gunpowder under favorable circumstances. =75.= In stony soil this method becomes very difficult if not impracticable; and when it can be used the preliminary explosion of dynamite vitiates to a greater or less degree the air of the shaft or gallery from which the boring is made, and also informs the enemy of the progress and intention of the miner. To remove the latter objections, the English authorities recommend the use of holes 6" or 8" in diameter, bored with earth-augers, charged to a length of 2 or 3 calibres, and well tamped. When applicable, this method is manifestly a great improvement upon the other; but the auger is so liable to be stopped by stones which a boring-bar might break or push to one side, that it can only be applied in very favorable soil. CHAPTER III. ORGANIZATION AND TACTICS OF MINES. =76. Organization of Mines.=--Underground warfare is conducted in the dark, in bad air, with constant danger of caving earth, suffocation by noxious gases, destruction of men and galleries by intentional explosions of hostile mines or accidental ones of our own, in addition to the usual dangers and difficulties of opening and supplying the mines under the close fire of the enemy. These considerations necessitate the rejection of all complicated systems in the attack, and in the work carried on by the defence during the siege.