tion of its being given in some future volume of the Transactions, in the most accurate and satisfactory manner.
But the ascertaining of the local and relative situations of mines, though of unquestionable interest to the geologist, can only be regarded as a link in the chain of inquiry. In order to render its value complete, it should be accompanied by a memoir, or rather a comprehensive history of each mine and of its connexion with those immediately contiguous to it on the same veins. But this could only be attained by years of unceasing and laborious inquiry on the spot. In the counting-houses of the most successful mines the only information ever committed to paper, in regard to the workings of the veins are the expenditure and income, together with a section of the vein from which the profit is reaped, without a single notice in regard to the tract of country through which it passes. Of the generality of unsuccessful mines, which form by far the greater proportion, all that is registered is the loss or expenditure; other information can only be obtained by a recourse to personal inquiries of the conductors or captains.
The following pages are principally intended to exhibit an outline of general facts relative to the veins of Cornwall, arranged under separate heads. In drawing up this sketch, such advantage has been taken of what has already been published on the subject as seemed consistent with the present object, carefully rejecting every thing doubtful, or hypothetical, and having in constant view the advantage of corroborating every assertion to the extent of my limited information, by a recourse to the peculiar circumstances of individual veins or mines. Though thus limited in its object and extent, it will I trust be found both consistent with its intention and accurate in its detail; nor will its service be trifling if, upon a subject so interesting, and on which little is known, it should be the means of inducing some of the