BLACK LEAD. 
472 
paper, and which renders it of such essential ser- 
vice to the artist ; especially as its marks can be 
entirely removed with a piece of the elastic resin 
known by the name of Indian rubber*. 
According to Brogniart, black lead appears to be 
entirely confined to the primitive earths. He says 
that it sometimes enters into the composition of 
the rocks which form these earths, sometimes it is 
found in lumps or in beds of a considerable thickness, 
and it is also met with in layers of argillaceous slate. 
In the department of Arriege, in France , it is found 
in large compact masses. It occurs likewise in the 
department of Mont Blanc ; in that of La Sture, 
near Vinay ; and in the mountain of Lubacco, 
where little veins of it are found in granite. In 
Spain it occurs in the mountains of Arragon, and 
near Casalla, and Ronda in the kingdom of Gre- 
nada; but none of these places are to be compared 
with Borrowdale, in England , for the production of 
black lead. This valley, which is situated in the 
south-east part of Cumberland, about four miles 
from Keswick, is enclosed by rude and lofty hills, in 
one of which the black lead is found in sufficient 
abundance to supply almost all the world. The 
mines are said to lie to the east of a very steep 
mountain, which forms the west side of the vale of 
Stomathwaite. There are two workings ; the lower 
one is about three hundred and forty yards above 
the level of the sea, and its perpendicular depth 
about 105 yards; the upper one is nearly 390 yards 
* See Syringe Tree. 
