THREE

LE T T E R S

ON

Mining and Smelting;

In which a Method is laid down,

Whereby these useful SCIENCESmay be greatly Improved.

To which, is added, a Fourth

L E T T E R;

Setting forth,

A Dl S CO VERY of an easy Method tosecure Ships Bottoms from Worms.

Written by

Diederici£ Wessel Linden, M. D.

Humbly inscribed, by the Editor,

To the Right Honourable the

Earl of H A L I F A X.

Fortuna {idem mutata navavitfed

Res ardua nouitatem dare, novis auEtoritatcm. Plin'.LONDON;

Printed for George Keith, Bookseller, atMercers-C has el, Cheapftde, Mdccl.