In the parish of Ludgvan were rich copper works, abounding with mineral and metallic fossils, of which he made a collection, and thus was led to study somewhat minutely the natural history of Cornwall. In 1750, he was admitted a Fellow of the Royal Society; and in 1754 he published, at Oxford, his "Antiquities of Cornwall" (2nd ed., London, 1769). His next publication was "Observations on the Ancient and Present State of the Islands of Scilly, and their Importance to the Trade of Great Britain" (Oxford, 1756). In 1758 there appeared his "Natural History of Cornwall" which includes a chapter on the inhabitants and their native language (about one ninth of the whole).