Page:Transactions of the Provincial Medical and Surgical Association, volume 2.djvu/120

 week, or a few inches daily, is often the whole amount of the united operations of 20 or 30 men. In loose lodes, and in killas districts, they often cut much more than this, but often they do not cut so much. It is to be recollected that the lode is very rarely so wide as the gallery, so that it becomes necessary, in order to continue the latter of the proper size, to hew through the solid rock on each side, which is often very hard, even when the lode is soft. The Cornish miner rarely sleeps or eats under ground, but returns to grass (the technical name of the surface) and to his home, often many miles distant, at whatever depth he may be working, when relieved by his successor. The mode of ascent and descent is by means of vertical ladders fixed in the shafts.

Water of Mines.─Any person who calls to mind the manner, object, and results, of the common process of sinking wells, will be prepared to expect the presence of water in mines. The quantity of this varies very much in different mines at the same time, and in the same mines at different times. Some of the circumstances that occasion this difference are very obvious, for instance, the topographical relations of the surface, the nature of the rock and lode, the number and size of the lodes, cross-courses, &c. Many galleries, both on the lode and through the country, are quite dry, but in general the reverse is true. Commonly the water oozes almost imperceptibly from the lode and walls of the galleries, and