206 MATTHEW FONTAINE MAURY ~ 



water-tight cases, will answer. I am not aware that 

 electricity was used by either of the belligerents in the 

 late American war for springing mines on land. 



"The cases for land-torpedoes should be shells cast 

 expressly for the purpose. The thickness of the shell 

 being from one-fourth to an inch, and even more, or less, 

 according to the size and the probable handling in trans- 

 portation. 



'^They should be spherical; only instead of a hole for 

 the fuse, as in a hollow shot, they should have a neck 

 like a bottle, with a cap to screw over — not in — the neck. 

 The case should be charged through the neck, and the 

 wires let in through two holes, counter-sunk, diametri- 

 cally opposite, the counter-sinking being for the purpose 

 of receiving pitch or other resinous matter to keep the 

 water out. The fuse, being adjusted to the wires, should 

 be held in its place by a string through the neck, while 

 the wires are drawn out taut and sealed within and with- 

 out. Having proved the fuse, first fill and then drive in 

 a wooden peg. Then fill the space between it and the 

 screw-cap with red lead, and screw down tight so as to 

 make it water-tight. Now' secure the tails of the wires 

 so that they will not be chafed or bruised, and the mine 

 is ready to be packed for transportation. They are 

 generally to be used in stone fougasses, the wire being 

 buried at convenient depths, and all marks of fougasses 

 and trenches removed as completely as possible. Any 

 number, not exceeding twenty-five or thirty, may be ar- 

 ranged in a single circuit for the ebonite ; but if the mag- 

 netic exploder of Wheatstone be preferred, and the 

 ground be perfectly dry, hundreds may be planted in a 

 ladder-circuit, which you have seen handled. 



"The operator may be at any distance from these 



