Copper Mines. Be 
stances, which divide the lode, and throw it right and left 
for a considerable distance. 
Veins of copper, it has been observed, run with regard to 
thetr longitudinal course, in a direction E. and W. With 
regard to their vertical course they are found to descend,. 
at times, in a direct perpendicular; but more usually on an 
inclination varying from a perpendicular to an angle of 45°. 
Their inclinations are also seldom uniform for many fathoms 
together, but are apt to vary, so as, at times, to form a 
waving line or to be even angular like steps. If a lode of 
ore, uniform in thickness and without intermission (as is often 
the case), could be laid open on one side, so as to be seen 
at one view, it would presenttotheeyea metalliclayer which 
had been until then condensed between layers of another 
substance; the same as if one supposes a plate of metal to 
be introduced between different plates or layers of slate, 
stone, or any other matter; and if the reader, by a stretch 
of imagination, can suppose layers of such description on a 
large scale to be occasionally bent horizontally, in rather 
zigzag lines, from E. to W., and to be at times, a little 
blended and confused, so that their homogeneous character 
be in certain parts destroyed, but otherwise to descend on 
inclinations as before mentioned, he will be able to form an 
idea of a mineral vein. When such vein has an inclination 
downwards towards the N., it is said to dip to the N.; and 
when in the opposite direction, it is said to dip to the S. 
The term “vein” gives the idea of a substance having 
its breadth equal to its thickness, and its thickness to its 
breadth—something running in a line or string—such as 
the veins of animals. But the term is improper when ap- 
plied to a vein of copper or other mineral, which is, in 
reality, a layer; and the only reason that the writer can 
assign for the term having been applied to minerals, is be- 
cause in excavations there is never any more of the layer 
exposed at any one time to view than that which, to a cer- . 
tain extent, may be said to resemble a vein; although to 
the eye of the mind it is presented in a very different form. 
The expression is, for the same reason, equally improper 
when applied to the veins in marble, but streaks or varie- 
gations. In the present treatise, however, the word has been 
and will be used in its commonly accepted sense. 
When a lode, vein (or layer), has been worked sufficiently 
both E. and W., upon one level or floor, it becomes _ neces- 
sary to descend; for which purpose it is usual to sink shafts 
