The different Sciences and Arts are digested into the Form of distinct Treatises or Systems; Including the LATEST DISCOVERIES AND IMPROVEMENTS; WITH THE NATURAL, CIVIL, MILITARY, AND COMMERCIAL HISTORY, AND BIOGRAPHY OF EMINENT MEN, A DESCRIPTION OF ALL THE COUNTRIES, CITIES, SEAS, RIVERS, &c. OF THE KNOWN WORLD. Including also THE WHOLE OF DR. JOHNSON'S DICTIONARY OF THE ENGLISH LANGUAGE. COMPILED FROM EVERY SOURCE OF DOMESTIC AND FOREIGN LITERATURE; AND ILLUSTRATED WITH AND A COMPLETE AND ACCURATE ATLAS. IN TWENTY THREE VOLUMES. .VOL. XV. LONDON: PRINTED FOR VERNOR, HOOD, AND SHARPE, 31, POULTRY; R. Morison, Priater, Perth. 1807. ENCYCLOPÆDÍA PERTHENSIS. MIN MINE ́INE. n.f. [mine, French; mwyn or man, Welsh, from maen lapis, in the plural meini.] 1. A place or cavern in the earth which contains metals or minerals. In your large heart was found a wealthy mine. Waller. -A workman, to avoid idleness, worked in a groove or mine-pit thereabouts, which was little teemed. Boyle-A mine-digger may meet with a gem, which he knows not what to make of. Boyle. -The heedlefs mine-man aims only at the obtaining a quantity of fuch a metal as may be vendible. Bale. 2. A cavern dug under any fortification that it may link for want of fupport; or, in mʊdern war, that powder may be lodged in it, which being fired at a proper time, whatever is over it ay be blown up and destroyed. What mine hath erft thrown down fo fair a tower? Sidney. Brid up the walls of Jerufalem, which you have broken down, and fill up the mines that you bat digged. Whitgift. Others to a city strong Lay fiege, encamp'd; by batt'ry, fcale and mine, Adaulting. Milton. (IIMINE, in the military art, (§ I. def. 2.) Re: Mix: ƒ II. in last volume, p. 720. From a great number of experiments, it appears, I. That the force of a mine is always towards the wekeft fide; fo that the difpofition of the chamber of a mine does not at all contribute to determe this effect. 2. That the quantity of pow. der must be greater or lefs in proportion to the greater or lets weight of the bodies to be raised, and to their greater or lefs cohesion; so that we mallow for each cubic fathom, of loofe earth, 9 or 10lb. Of firm earth and strong fand, 11 or 12 b. Of flat clayey earth, 15 or 16 lb. Of new mafonry, not trongly bound, 15 or 20 lb.; and of old mafonry, well bound, 25 or 30 lb. 3. That the aperture, or entonnoir of a mine, if rightcharged, is a cone, the diameter of whofe VOL. XV. PART L. bafe is double the height taken from the centre of the mine. 4. That when the mine has been overcharged, its entonnoir is nearly cylindrical, the diameter of the upper extreme not much exceeding that of the chamber. 5. That befides the fhock of the powder against the bodies it takes up, it likewife crufhes all the earth that borders upon it, both underneath and fidewife. To charge a mine fo as to have the most advantageous effect, the weight of the matter to be carried must be known; that is, the folidity of a right cone, whofe bafe is double the height of the earth over the centre of the mine: thus, having found the folidity of the cone in cic fathoms, multiply the number of fathoms by the number of pounds of powder nes ceffary for raising the matter it contains; and if the cone contains matters of different weights, take a mean weight between them all, always ha ving a regard to their degree of cohefion. As to the difpofition of mines, there is but one general rule, viz. that the fide towards which one would determine the effect be the weakest; but this varies according to circumftances. The calculation of mines is generally built upon this hypothefis, That the entonnoir of a mine is the fruftum of an inverted cone, whofe altitude is equal to the radius of the excavation of the mine, and the diameter of the whole leffer bafe is equal to the line of leaft refiftance; and though these fuppofitions are not quite exact, yet the calculations of mines deduced from them have proved fuccef-ful in practice; for which reafon this calculation should be followed till a better and more fimple one be found out. M. De Valliere found that the entonnoir of a mine was a parabaloid, which is a folid generated by the rotation of a femiparabola about its axis; but as the difference between thefe two is very infignificant in practice, that of the fruftum of a cone may be used. (III. 1.) MINE in natural history, (§ II. def. 1.) implies a deep pit under ground, whence various kinds of minerals are dug out; but is more. parti. A cularly |