be that of a circle seventy-five or eighty yards in diameter. Twenty mines would therefore serve for a mile. Several miles may be planted in a night and the assailants may be enticed, or invited out in the morning. Passes before an invading army may be mined in advance and thus if he cannot be destroyed, his progress may be so retarded by dress mines or sham mines as almost literally to dig his way.
The power to telegraph through these torpedoes is of little consequence, in as much as there need be but one station and one operator. Using the testing fuse manufactured by Abel and a weak voltaic current, the operator can at any time satisfy himself as to continuity. Thus "bridge" and "gulfs" or "breaks" are not required for the land as they are in sea-mining. Ebonite has the further advantage on land that it takes but a single wire.
Forts may be protected against assault and your own rifle pits from occupation by an enemy simply by a proper distribution of these new engines of war. They may be planted line within line and one row above another, and so arranged that volcanoes can be sprung at will under the feet of assualting columns. And these improvements and discoveries enable the engineer at small cost, and short notice effectually to defend any roadstad, or block any river, harbour or pass against the land and naval forces of an enemy without in the least interfering with the free use of the same by friendly powers.
To this admirable state of efficiency was new and terrible science of war perfected, chiefly by the Confederate Navy, and mainly through the instrumentality of its faithful, and devoted officer Captain Matthew F. Maury, and his brave and daring young assistants. Minor, Davidson, Kennon, Dixon, Glassel, and many others, and those crews of the "Hundley," who moved by the lofty
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