Treffle Mines, are mines with two chambers only.
T-Mines, so called from their great resemblance to that letter. They are double mines, having four lodgments.
Double T-Mines, have eight lodgments, and four doors.
Triple T-Mines, have twelve lodgments, and six doors.
Double Treffle Mines, have four lodgments, and eight doors.
Triple Treffle-Mines, have six lodgments, and twelve doors.
MINING, in the art of war, is become one of the most essential parts of the attack and defence of places; so much artillery is used, that nothing above ground can withstand its effects; the most substantial ramparts and parapets can resist but a short time; the outworks, though numerous serve only to retard for a time the surrender of the place.
History informs us, that mines were made long before the invention of gun powder; for the ancients made galleries or underground passages, much in the same way as the moderns, from without, under the walls of the places, which they cut off from the foundation, and supported them with strong props; then they filled the intervals with all manner of combustibles, which being set on fire burnt their props and the wall being no longer supported, fell, whereby a breach was made.
The besieged also made under-ground passages from the town under the besieger’s machines, by which they battered the walls, to destroy them; which proves necessity to have been the inventress of mines, as well as of other arts.
The first mines, since the invention of gunpowder, were made in 1487, by the Genoese, at the attack of Serezanella, a town in Florence; but these failing, they were for some time neglected, till Peter Navarro, being then engineer to the Genoese, and afterwards to the Spaniards in 1503, against the French, at the siege of the castle del Ovo, at Naples, made a mine under the wall, and blew it up. In consequence of which the castle was taken by storm.