The removal of the ore, as conducted from the levels by which access to it has thus been gained, may be carried on either by "direct" or by "inverted grades,"--that is, either by breaking it up from underneath, or down from overhead, in each of the levels which have now been described,--or, as it is more commonly called in mining language, by "understoping" or by "overstoping." When the breadth of the lode is equal to that of the level, it is perhaps not very material which plan be adopted. But when, as at Oldham, Montague, or Tangier, the lodes are only of moderate-width, and much barren rock, however soft and yielding, has, of necessity, to be removed along with the ore, so as to give a free passage for the miner through the whole extent of the drifts, we shall easily understand that the working by inverted grades, or "overstoping," is the only proper or feasible method. In this case, the blasts being all made from the roof, or "back," as it is called, of the drift, the barren or "dead" rock containing no gold is left on the floor of the drift, and there is then only the labor and expense of bringing the valuable quartz itself, a much less amount in bulk, to the surface of the ground. The accumulating mass of the dead rock underfoot, will then be constantly raising the floor of the drift, and as constantly bringing the miners within convenient working-distance of the receding roof. In the case of "understoping," however, in which the blasts are made from the floor of the drift, it will be perceived that all the rock which is moved, of whatever kind, must equally be brought to the surface, which entails a much greater labor and expense in the hoisting; and gravity, moreover, instead of cooperating with, counteracts, it will easily be understood, the effective force of the powder. Such is a necessarily brief and condensed account of the novel and interesting branch of industry which has thus been opened almost at our very doors. The enterprise is as yet merely in its infancy, and will doubtless for some time be regarded with incredulity and even distrust. But if there be any weight to be attached to the clearest, most explicit scientific and practical testimony, we must henceforth learn to look upon Nova Scotia with an increased interest, and, perhaps a somewhat heightened respect. The spies that came out of Canaan were not, at any rate, more completely unanimous in their reports of the richness of the land than the eminent persons who have been sent to examine the auriferous lodes of our Acadian neighbors. If gold does not really exist there, and in very remunerative quantities, it will be hard for us henceforth to believe in the calculations of even a spring-tide, a comet, or an eclipse.