4 per ton. In 1718 John Coster gave a
great impulse to the trade by draining some of the deeper mines, and
instructing the men in an improved method of dressing the ore. The trade
thereafter progressively increased, and in 1851 the mines of Devon and
Cornwall together were estimated to furnish one-third of the copper
raised throughout Europe, including the British Isles. Antimony ores and
manganese are found, and some lead occurs, being worked without great
result. Iron in lodes, as brown haematite, has been worked near
Lostwithiel and elsewhere. In the St Austell district the place of tin
and copper mining has been taken by that of the raising and preparation
of china clay. Granite is largely quarried in various districts, as at
Luxulian (between St Austell and Lostwithiel), and in the neighbourhood
of Penryn. This is the material of London and Waterloo Bridges, the
Chatham docks, and many other great works. It is for the most part
coarse-grained, though differing greatly in different places in this
respect. Fine slate is quarried and largely exported, as from the
Delabole quarries near Tintagel. These slates were in great repute in
the 16th century and earlier. Serpentine is quarried in the Lizard
district, and is worked there into small ornamental objects for sale to
visitors; it is in favour as a decorative stone. Pitchblende also
occurs, and is mined for the extraction of radium.

_Fisheries._--The fisheries of Cornwall and Devon are the most important
on the south-west coasts. The pilchard is in great measure confined to
Cornwall, living habitually in deep water not far west of the Scilly
Isles, and visiting the coast in great shoals,--one of which is
described as having extended from Mevagissey to the Land's End, a
distance, including the windings of the coast, of nearly 100 m. In
summer and autumn pilchards are caught by drift nets; later in the year
they are taken off the northern coast by seine nets. Forty thousand
hogsheads, or 120 million fish, have been taken in the course of a
single season, requiring 20,000 tons of salt to cure them. Twelve
millions have been taken in a single day; and the sight of this great
army of fish passing the Land's End, and pursued by hordes of dog-fish,
hake, and cod, besides vast flocks of sea-birds, is most striking. The
principal fishing stations are on Mount's Bay and at St Ives, but boats
are employed all along the coast. When brought to shore the pilchards
are carried to t