militaire, Fr.) By this phrase we mean plication cannot become the former.To constitute the latter, requires the assemblage of some of the noblest at tributes of our nature: that power of mind, that grasp of thought, which seizes almost every thing, as if by intuition; which thinks, decides and acts, in the same moment; which forms the best possible judgment in the shortest possible time; which is not only cool and collected, but is roused and excited by danger; must all be united to adorn the character of a great general. Add to these qualities great powers of discrimination, a constant attention to the study of the higher branches of his profession, an anxious imitation of the great models which antiquity and modern times afford, and, above all, the posses sion of that military imagination, of which the king of Prussia speaks in his instructions to his generals, and without which there can be no real excellence or superiority. You, who are conscious that you are thus endowed, may, with firm and assured step, approach the sanctuary; view, with the eye of antici pated hope, your niche in the Temple of Fame, saying, with Correggio-Anché io son pittori. MINE, in a military sense, implies a subterraneous passage dug under the wall or rampart of a fortification, for the purpose of blowing it up by gunpowder. Counter-MINES, are those made by the besieged, whereas mines are generally made by the besiegers. Both mines and counter mines are made in the same manner, and for the like purposes, viz. to blow up their enemies and their works; only the principal galleries and mines of the besieged, are usually made before the town is besieged, and frequently at the same time the fortification is built, to save expence. Eventer la MINE, Fr. to spring a mine. When used figuratively, this expression signifies to discover a plot, or make it known. It likewise serves to express the failure of any expedition or undertaking. Definitions of MINES. A mine is a subterraneous cavity made according to the rules of art, in which a certain quantity of powder is lodged, which by its explosion blows up the earth above it. that the figure produced by the explosion is a paraboloid, and that the center of the powder, or charge, occupies the Focus. The place where the powder is lodged is called the chamber of the mine, or fourneau. The passage leading to the powder is called the gallery. The line drawn from the center of the chamber, perpendicular to the nearest surface of the ground, is called the line of least resistance. The pit or hole, made by springing the mine, is called the excavation. The fire is communicated to the mines by a pipe or hose, made of coarse cloth, whose diameter is about 14 inch, called a saucisson (for the filling of which near half a pound of powder is allowed to every foot), extending from the chamber to the entrance of the gallery, to the end of which is fixed a match, that the miner who sets fire to it may have time to retire, before it reaches the chamber. To prevent the powder from contracting any dampness, the saucisson is laid in a small trough, called an auget, made of boards, three inches and a half broad, joined together, lengthwise, with straw in it, and round the saucisson, with a wooden cover nailed upon it. Foyer, Fr. Focus, or Center of the Chamber. Some authors call the end of the saucisson that comes within the work, and which is to be set fire to, the foyer, or focus: but by most people, this is generally understood to be the center of the chamber. Galleries and Chambers of MINES. Galleries made within the fortification, before the place is attacked, and from which several branches are carried to different places, are generally 4 or 4 feet wide, and 5 or 5 feet high. The earth is supported from falling in by arches and walls, as they are to remain for a considerable time; but when mines are made to be used in a short time, then the galleries are but 3 or 34 feet wide, and five feet high, and the earth is supported by wooden frames or props. The gallery being carried on to the place where the powder is to be lodged, the miners make the chamber. This is generally of a cubical form, large enough to hold the wooden box, which contains the powder necessary for the charge: the box is lined with straw and sandbags, to prevent the powder from contracting dampness. The chamber is sunk something lower than the gallery, if the soil permits; but where water is to be apprehended, it must be made higher than the gallery; otherwise the besieged will let in the water, and spoil the mine. Quantities of powder to charge MINES. Before any calculation can be made of the proper charge for a mine, the density and tenacity of the soil in which it is to be made, must be ascertained, either by experiment, or otherwise; for, in soils of the same density, that which has the greatest tenacity, will require the greatest force to separate its parts. The density is determined by weighing a cubic foot (or any certain quantity) of the soil; but the tenacity can only be determined by making a mine. The following table contains experiments in six different soils, which may be of some assistance to form a judgment of the nature of the soil, when an actual experiment cannot be had. Nature RULES. The nature of this soil, by the table, requires ten pounds of powder to 216 CALCULATION. cubic feet. 1. The diameter of the excavation 400 is 20, and its square 400 Therefore the sum to be reserved is 800 1. To the square of the diameter of Which leaves the remainder the excavation, add the square of double the line of least resistance, and reserve the said sum. 2. Multiply the square root of the reserved sum by double the line of least resistance, and subtract the product from the same sum. 3. Multiply half the remainder by the line of least resistance, and 1.57 times the product, will give the solidity of the excavation. } 3. Half the remainder is Gives the product Gives the solidity of the exca- 4. The charge will then be deter- 4. mined from the nature of the soil, as in the following example. EXAMPLE I. It is required to make a mine in the second sort of soil, mentioned in the foregoing experiments, which shall have a line of least resistance of 10 feet, and the diameter of its excavation 20 feet; what will be the proper charge? 566 234 117 10 1170 1.57 feet 1836.9 1. Diam. of excavation The sum to be reserved is 2.903090 800 2. Square 9.000000 Charge = 100 co. ar. Constant logarithm 0.103804 1. Find the solidity of the earth to be raised, by a proportion from the nature of the soil, and multiply it by 1.27.— Divide the product by the line of least resistance, and to the quotient add the To which add the square square of the line, of least resistance: reserve the sum. 2. Multiply the square root of the sum reserved by twice the line of least resistance, and add the product to the said sum, and from the result subtract three times the square of the line of least resistance; so will the square root of the remainder be the diameter of the required excavation. of line of least resist- 2.396865 249.4 100.0 Sum to be reserved is 2.543323 349.4 Half of which logar. 1.271661 1.301030 Product to be added is 2.572691 373.8 And there remains 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 3 Y against the sides and bottom of the Tas done, the rICES SHOUT MONORA the props are £ut 40 17 stás Thủ ding, and runner or Tysnes, Mau those next to them, and those to their neighbours; and this communication will thus continue in a decreasing pro portion, 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. Different sorts of MINES are as follow: Fougasses, are a sort of small mines, frequently made before the weakest part of a fortification, as the salient amges ami faces, not defended by a cross Prelle MINES, are mines with two ambers only. T-MINES, so called from their great sembiance to that letter. They are cuole mines, having four lodgments. Double T-MINES, have eight lodg ments, and four doors. Triple T-MINES, have twelve lodg ments, and six doors. Double Treffle MINES, have four auer, with lodgments, and eight doors. and the www over it: eat care must a auget, for 8820 in MINES, from agine a large globe nevus in all its parts, quantity of powder lodged se as to produce a proper our bursting the globe; by 2020 the powder, it is evident, Po kokson will act all round, to evane de pàstacles which oppose se; and as the particles of the a a porous, they will compress cd see in proportion as the flame sex and the capacity of the chamge increases likewise: but the partiof earth next to the chamber will ducate a part of their motion to Triple Treffle MINES, have six lodg ments, and twelve doors. MINE sans cervelle, Fr. literally signi fies a mine without brains. This expression is used among miners to describe any unthankful piece of ground, which has no consistency within itself, either at the top of the gallery, or on its sides, and is rendered firm by various expedients. MINERS, are generally soldiers: most of the foreign regiments of artille ry have each a company of miners, com manded by a captain and two lieute nants. 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 arti ficers are ordered for that purpose. MINERVA, (Minerve, Fr.) accord ing to the heathen mythology, the god dess of wisdom, of war, and of the arts; she was also looked upon as the goddess of peace. She is generally represented with a helmet on her head, a shield on her arm, with a lance and an olive branch in her hand; several mathematical instruments, and the figure of an owl near her, as the emblem of wisdom. MINING, |
