pregnated by sulphate of copper, as to leave some of e metal in its ashes when burned. When this was asrtained, the injured vegetation guided to the vein. By e retention, therefore, of these contaminated waters, in e soil near the vein, it may become unfit for vegetaon, and thus the sterility of certain patches of ground, ay indicate the existence of metallic substances in the strict. (Mr. Brande, who writes the above account, has not ated what species of copper was discovered. It was, owever, undoubtedly a sulphuret, and from the decomsition of which, the sulphuric acid was produced, hich uniting with the oxide of the metal, formed sulate of copper. In the Anglesea copper-mine, considerle quantities of the metal are obtained from the natural lution of the sulphate in water. This is done by throwg in pieces of waste iron, on which the copper is prepitated.) "There are no class of persons," continues Mr. Brande, more curiously superstitious than miners; and hence a riety of omens, connected with the interference of agents om the spiritual world, are among the items of their eed. Sometimes while under ground, they fancy they ear another pick at work, announcing the presence of little man, or pixey-knocker, in some neighboring cavern, d the consequent vicinity of a good course of ore. Somenes the divining rod is resorted to, as a means of finding e ore; and sometimes it is said that flames of light, ancing about a mining district, have suddenly perched on the looked for vein; a circumstance not improbable, ad perhaps referable to the power of the vein to conduct ectricity." The habits, however, of the miner, are those of indusy and perseverance, which sometimes tempt him to exoits that excite astonishment at his venturous hardihood. The very idea of a descent beneath the surface of the rth, has something in it of the terrible," says Mr. Philos, "and at which those shudder who are unacquainted ith practical mining; but such is the force of habít, that by other employment rarely tempts him to forsake his vn. The occasional perils of his occupation are scarcenoticed, or if noticed, are soon forgotten. He walks, ten in the middle of the night, and in all weathers, two, three, or more miles, to the mine, undresses, and puts and the over the underneat wave; w have the leagues, boisterous nodule, a rolling u and terrif many tim carry off found tha most insta ground to trating to with the These tu solved to his underground clothes, and with his tools, slung r his shoulder, descends to a depth of 1000 or 1200 assisted by the light of a small candle, and works he bottom of the mine six or eight hours, amidst the se of the working of the pumps, with as much alacrity with as little sense of danger, as he would feel amidst ordinary occupations above ground. We should be ined to feel pity for the wretch, who, as an atonement his crimes, should be compelled to undergo what the nish miner voluntarily undertakes for a small pittance, that even of an uncertain amount."—W. Phillip's 1. Trans. ne of the mines in the parish of St. Just, is wrought ly 500 feet under the sea, beyond low-water mark; the sea, in some places, is only about eighteen feet the back of his workings; insomuch that the miners =rneath hear the break, flux, ebb, and re-flux of every e; which, upon the beach overhead, may be said to the run of the Atlantic ocean for many hundred ues, and consequently are amazingly powerful and erous. They also hear the rumbling noise of every le, and fragment of a rock, which are continually ng upon the submarine stratum; which altogether e a kind of thundering roar, which would surprise terrify the stranger. Add to this, that several parts e land which were richer than others, have been creetly hulked, and worked within four feet of the whereby, in violent stormy weather, the noise overhas been so tremendous, that the workmen have times deserted their labor, under the greatest fear, he sea should break in upon them.-Pryce's Minera Cornubiensis. former times, when a vein of metal was discovered, s worked to a certain depth, and then often aband, in consequence of the insufficiency of the pumps to off the water, or the expense incurred in their erecand working. In certain situations, however, it was I that this water run off at lower levels, and that in instances it might be carried away by an undernd tunnel, commencing at the foot of the hill, peneg to the vein, and thus forming a communication the working of the mine, and a neighboring valley. e tunnels are now called adits, and when it is re bout six feet high, and two and a half wide, is begun at e bottom of the neighboring valley, and driven up to the ein for the purpose of carrying off the water; or if a ine has an engine to raise the water from a greater epth than that of the entrance of the adit, the engine en, instead of having to lift the water to the surface, rows it off, with diminished labor, at the adit. In gen al, adits are nearly horizontal, for although a declivity ould accelerate the drainage, it would enter the mine at less depth. The importance of draining mines by adits as led to some gigantic undertakings of this kind. The reat Cornish adit, commences in a valley above Carnon, ear the sea, and branches off in its course in several dictions to about fifty mines. Most of the mines are far elow the level of the adit, the water being raised into it means of steam engines. The entire length of this lit, with its various branches, is about thirty miles. But e greatest length of any one branch from its mouth to e mine, is that of Cardrew Mine, which is about five and half miles. The greatest depth of any part of this adit at Wheel Hope, where it is about 400 feet deep. It npties itself into Falmouth harbor. Several great works the same kind exist in different parts of Great Britain. he adit belonging to the Duke of Bridgewater's coal ines, is nearly thirty miles long, and navigable for small pats. Where an adit is of any considerable length, it is obous that the air would become stagnant in it, so that the orkmen would be unable to proceed. To prevent this, ad also to enable them to remove the produce of the cavation without transporting it to great distances, perendicular openings, calfed shafts, are made at various inrvals. From these shafts, levels, or galleries, are driven different directions, either for exploring for new veins, for removing the contents of those already known.ze Brande's Geology. PHENOMENA OF SPRINGS AND WELLS. The origin of common springs is easily understood. he water which falls on the surface of the earth, peneates its substance, until meeting with a stratum of clay, e surface of a continuous rock, which hinders its de, it accumulates, and taking the direction given by impediments, continues its course, until meeting with perture, gushes out in the form of a spring. appose a, fig. 44, to be a gravel hill, and b, strata of or rock, impervious to water. The fluid percolathrough the gravel would reach the impervious straong which it would run until it found an outlet at c, e foot of the hill, where a spring would be formed. water in the earth observes the law of gravity, springs most commonly found lower than their sources. When ever the fluid is intercepted by a dyke, which rises as as its source, the hydrostatic law of tending to a level, carry it as high as its source; though this in fact is ably not a common circumstance, since the pressure e water generally will find an outlet before it rises to a height. he people of Artois in France, for a long time, have in the practice of boring into the earth, until they a sheet or vein of water which rises to the surface. se are called Artesian wells, because the method was invented, or employed in Artois. his method has for many years been practised in r parts of Europe, and more recently in this country. size of the boring is usually three or four inches in eter, and to prevent its sides from falling in when it es through a stratum of sand, there is introduced a ed tube, which in Artois, is made of wood, but in r countries of copper, or other metal. It often hapthat after passing through hundreds of feet, without ess, a vein of water is pierced, which immediately nds to the surface, and flows over the end of the tube. first rush of the water is sometimes so violent as to w it many feet above the surface, where for a time it like a ificial fountain and then continues to run ce to the great disappointment of the operator. This vio- In some instances large quantities of water have been It Sometimes borings for Artesian wells are entirely withat success. Thus, at Toulouse, in France, the excava on was carried to the immense depth of 1260 feet, and pandoned without finding water. In most places, indeed, ere is no doubt but success must depend on chance, since either skill nor experience in ordinary circumstances, un ascertain beforehand the direction of a water vein. pears, however, that in certain situations, water bearing rata underlay considerable extents of country, as will ppear by the following account. In the country about Modena, in Italy, to find water, ey dig through several kinds of soil, until they come to stratum of hard calcareous clay, which resembles chalk. ere they begin their mason work, and build the wall at eir leisure, carrying it up to the surface, without the ast sign of water. But experience has taught the worken not to expect it until they pierce this stratum, when never fails to reward their labors. When the well is nished they bore through this hard stratum with a long iger, but take care to leave the well before they draw out again; which when they have done, the water rings up into the well, and in a short time rises to the rim, or in some instances overflows into the neighboring alley. The source of these wells is supposed to be in the Apenine mountains, which lie not a great distance from Iodena, and to which the impervious stratum does not ach. The water from the mountains, therefore sinks elow this stratum, at a distance from these wells, and is us prevented from rising to the surface until this is ierced. the fluid except ab its lower this is pi represents In man tinue to d S may be by the we dykes, c other. |