he richest copper mines in the world,
and by far the largest and most profitable in the kingdom. The divided
profits during this period amounted to L1,192,960. But the mining
interests of Devonshire are affected by the same causes, and in the
same way, as those of Cornwall. The quantity of ore has greatly
diminished, and the cost of raising it from the deep mines prevents
competition with foreign markets. In many mines tin underlies the
general depth of the copper, and is worked when the latter has been
exhausted. The mineral products of the Tavistock district are various,
and besides tin and copper, ores of zinc and iron are largely
distributed. Great quantities of refined arsenic have been produced at
the Devon Great Consols mine, by elimination from the iron pyrites
contained in the various lodes. Manganese occurs in the neighbourhood
of Exeter, in the valley of the Teign and in N. Devon; but the most
profitable mines, which are shallow, are, like those of tin and
copper, in the Tavistock district.

The other mineral productions of the county consist of marbles,
building stones, slates and potters' clay. Among building stones, the
granite of Dartmoor holds the foremost place. It is much quarried near
Princetown, near Moreton Hampstead on the N.E. of Dartmoor and
elsewhere. The annual export is considerable. Hard traps, which occur
in many places, are also much used, as are the limestones of
Buckfastleigh and of Plymouth. The Roborough stone, used from an early
period in Devonshire churches, is found near Tavistock, and is a hard,
porphyritic elvan, taking a fine polish. Excellent roofing slates
occur in the Devonian series round the southern part of Dartmoor. The
chief quarries are near Ashburton and Plymouth (Cann quarry). Potters'
clay is worked at King's Teignton, whence it is largely exported; at
Bovey Tracey; and at Watcombe near Torquay. The Watcombe clay is of
the finest quality. China clay or kaolin is found on the southern side
of Dartmoor, at Lee Moor, and near Trowlesworthy. There is a large
deposit of umber close to Ashburton.

_Climate and Agriculture._--The climate varies greatly in different
parts of the county, but everywhere it is more humid than that of the
eastern or south-eastern parts of England. The mean annual temperature
somewhat exceeds that of the midlands, but the average summer heat is
rather less than that of the southern coun