Lye’ 
~~ 
’ 
which may have been running with it E. and W. These 
passages or drivings, the writer supposes to have been con- 
tinued for about forty feet each way ; that at such distance 
one of them has been discontinued, and that the other has 
arrived at what is termed a lode. He supposes this lode, 
or vein, to have been immediately pursued by fresh drivings 
E. and W., branching off from the original driving which 
was N. and S.; and thus he has endeavoured to give to the 
reader some idea of the commencement of a mine. Hitherto 
the operators have been working without any other air than 
what has been admitted through the perpendicular shaft ; 
but it is to be observed that, as the excavation proceeds, 
such air becomes more and more rarified, until, upon com- 
mencing transverse drivings to pursue the lode, the men are 
no longer able to work ; and, in addition to their own per- 
sonal and physical disabilities, they find that the candles 
will not continue to burn; so that there becomes an ab- 
solute necessity for fresh air. In this dilemma, air is gene- 
rally introduced by the sinking of another shaft over the 
spot where the transverse excavations commence; for air 
(though it may continue sufficiently strong in a direct line 
for a long distance,) becomes very much attenuated by the 
turning of a corner, which seems to show that air is by no 
means so perfect a fluid as is generally thought. 
Where a rise for this purpose is impracticable by reason 
of water, or too great a mass of superincumbent ground, or 
any other cause presenting difficulty, air is introduced by 
means of pipes, which, at the mouth of the shaft, are fur- 
nished with a sort of windsail; and in mines where air has 
to be introduced by pipes for a considerable distance, it 
becomes necessary to have it propelled by pumps or bellows. 
In the progress of operation, the parts containing ore are 
disengaged from the surrounding substance with great care, 
in order to preserve the former as entire as possible; but 
some ores are of so friable a nature that it is impossible to 
prevent a portion of them from falling among the fragments 
of rock. Whilst miners are employed in extracting the 
vein in the mine, others (in order that no time be lost), are 
engaged in sinking fresh shafts on the outside, with a view 
of striking the same lode at the same depth further to the 
E. and W., and working so that the whole should at last 
unite and form one line of excavation. In the course of 
this line, frequent ramifications occur, as well as occasional 
variations in point of quantity, and very often obstacles 
present themselves by the intervention of hard rocky sub- 
372 Copper Mines, 
