Part 306

Numb. Logar. Numb. Cubic feet = 216 2.334454 Powder 11lb. co. ar. 8.958607 Charge = 100 2.000000 Line of least resist. 10 co. ar. 9.000000 Constant logarithm 0.103804 -------- 2.396865 249.4 ----- To which add the square of line of least resistance 100.0 ----- Sum to be reserved is 2.543323 349.4 -------- Half of which logar. 1.271661 Twice line of least resistance, 20, 1.301030 -------- Product to be added is 2.572691 373.8 ----- The result is 723.2

From which subtract thrice the square of the line of least resistance 300.0 ----- And there remains 2.626546 423.2

Half of which logar. is 1.313273 20.57 feet, the diameter of the excavation required.

Loading and stopping of MINES. The gallery and chamber being ready to be loaded, a strong box of wood is made of the size and figure of the chamber, being about ¹⁄₃d or ¹⁄₄th bigger than is required for containing the necessary quantity of powder: against the sides and bottom of the box is put some straw; and this straw is covered over with empty sand bags, to prevent the powder from contracting any dampness: a hole is made in the side next the gallery, near the bottom for the saucisson to pass through, which is fixed to the middle of the bottom, by means of a wooden peg, to prevent its loosening from the powder: or that, if the enemy should get to the entrance, he may not be able to tear it out. This done, the powder is brought in sand bags, and thrown loose in the box, and covered also with straw and sand bags; upon this is put the cover of the box, pressed down very tight with strong props; and, to render them more secure, planks are also put above them, against the earth, and wedged in as fast as possible.

This done the vacant space between the props are filled up with stones and dung, and rammed in the strongest manner: the least neglect in this work will considerably alter the effect of the mine.

Then the auget is laid from the chamber to the entrance of the gallery, with some straw at the bottom; and the saucisson laid in it, with straw over it: lastly, it must be shut with a wooden cover nailed upon it. Great care must be taken, in stopping up the gallery, not to press too hard upon the auget, for fear of spoiling the saucisson, which may hinder the powder from taking fire, and so prevent the mine from springing. The gallery is stopped up with stones, earth, and dung, well rammed, 6 or 7 feet further from the chamber than the length of the line of least resistance.

Globe of compression in MINES, from Belidor. If you imagine a large globe of earth homogeneous in all its parts, and, a certain quantity of powder lodged in its centre, so as to produce a proper effect without bursting the globe; by setting fire to the powder, it is evident, that the explosion will act all round, to overcome the obstacles which oppose its motion; and as the particles of the earth are porous, they will compress each other in proportion as the flame increases, and the capacity of the chamber increases likewise; but the particles of earth next to the chamber will communicate a part of their motion to those next to them, and those to their neighbors; and this communication will thus continue in a decreasing proportion, till the whole force of explosion is entirely spent; and the particles of earth beyond this term, will remain in the same state as they were at first. The particles of earth that have been acted upon by the force of explosion will compose a globe, which Mr. Belidor calls the globe of compression.

MINERS, in a military sense, are generally soldiers: most of the European regiments of artillery have each a company of miners, commanded by a captain and two lieutenants. When the miners are at work in the mines, they wear a kind of hood, to keep the earth that falls out of their eyes. In the English service the artificers are ordered for that purpose.

MINERS tools, consist in several sorts of spades, wheel-barrows, axes, hand-levers, chissels, sounding-augres, sledge-hammers, masons’ hammers, mattocks, augets, plummets, miner’s rule, and miner’s dial, &c.

Different sorts of MINES, are as follows:

Fougasses, are a sort of small mines, frequently made before the weakest parts of a fortification, as the salient angles and faces, not defended by a cross fire.

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.

M. Valliere relates the same story, but differs in the name of the engineer; he says it was Francis George, an Italian, who, serving at Naples in quality of architect, proposed to Peter Navarro, the Spanish governor to take this castle by mines.

Names of every thing used in MINING.

Auget, a kind of small trough, made of strong inch boards, about 4 inches square, in which the saucisson is laid in straw, to prevent the powder from contracting any dampness.

Chamber, the place where the powder is lodged, being first put in cubical boxes made for that purpose.

Excavation, Entonnoir, the pit or hole made by a mine when sprung.

Focus, the centre of the chamber where the powder is lodged.

Fougas, a kind of small mine.