130 Mr. William Phillips on the Veins of Cornwall, 



objects of the miner is to bring home an adit to it. An adit is a 

 water course, or rather an underground passage, about 6 feet high 

 and 2i wide, and is begun at the bottom of a neighbouring valley 

 and driven up to the vein, for the purpose of draining it of water 

 above their point of contact. In the event also of the mine having a 

 steam engine upon it to raise the water from a still greater depth, it 

 is not raised by the engine to the surface, but delivered into the 

 adit. The general level of the mining-country east and west of 

 Redruth is, according to Dr. Berger, from 350 to 450 feet above 

 that of the sea, except where the granite overtops the schist, as in 

 the instances of Carn-brae, Carn-math, and some few other hills, the 

 summits of which are at a considerably greater elevation. This 

 general level of the country is intersected by frequent vallies, which 

 afford great advantages for the formation of adits, and consequently 

 for the carrying away of the water from the mines. One adit fre- 

 quently serves this purpose, for 2, 3 or more mines. Pryce, who 

 published his work, entitled Mineralogia Cornubiensis, about 30 

 years ago, says p. 148, * Though we seldom see an adit half a mile in 

 length, there are 2 or 3 of three times that length, these are the 

 longest I know of.* But since his time, one has been driven through 

 a considerable tract of country at the lowest possible depth, as its 

 mouth or extremity is nearly on a level with the water in one of the 

 creeks of Falmouth harbour, into which it empties ; and being below 

 all other adits in that neighbourhood, it is called the deep adit. It does 

 not run in one course, either direct or circuitous, the whole of its 

 way ; but taking into calculation its various branchings in and 

 through the numerous mines (those of Gwennap) which it relieves 

 of their water, it may be said to be about 24 miles in length. 



Taking into consideration the purpose of an adit, it might be 

 presumed that it is wrought on an inclined plane from the place at 



