Page:Transactions of the Geological Society, 1st series, vol. 2.djvu/321

Rh other in these respects, and of course some may be said to be more perfect than others.

The result however of the whole has been the execution of works of extraordinary magnitude, with unparalleled dispatch; the pursuit of the difficult task of discovery with the greatest effect, and a vast increase in the produce of the metals, more particularly of copper, in the last fifty years.

The mines of Cornwall have furnished such supplies that the British manufacturers are no longer dependent on other countries for an article of raw material of the first importance to their trade, while in the space of less than a century, an increase, amounting to the annual value of near a million sterling, has made England one of the sources whence the world is now supplied with copper, instead of relying for this article upon the mines of Germany or Sweden.

The grant for working a mine is called a set, and is usually taken by one or more persons from the proprietor of the land in which a load maybe found, except in such cases of tin-mines as are anciently embounded according to the provisions of the stannary laws, whereby a right of working for this metal is obtained. No custom or ancient law however prevails as to copper or lead in the stannaries, and therefore all agreements for searching for, or working these metals, are made upon such terms as are decided on by the contracting parties. The owner of the land, in the technical language of the district, is called the lord, and the parties who engage to work the mine are called adventurers.