“This material, in the Chinese way of speaking, constitutes the bones, as the Petunse does the flesh, of china ware. It is a white talcy earth, found in our granite countries, both in the counties of Devon and Cornwall. It lies in different depths beneath the surface. Sometimes there shall be a fathom or more of earth above it, and at other times two or three feet. It is found on the sides of hills, and in valleys; in the sides, where, following the course of the hills, the surface sinks, or is concave, and seldom, I believe, or never where it swells, or is convex. By what I have observed, it is by no means a regular stratum, but is rather in bunches or heaps, the regular continuance of which is frequently interrupted by gravel and other matters. At times there are veins of it among the solid rocks, when it is constantly very pure from gravel. I have a piece by me of this kind, very fine. “There are inexhaustible stores of this Caulin in the two western counties. The use it’s commonly put to is in mending the tin furnaces and the fire-places of the fire-engines, for which ’tis very proper. The sort I have chiefly tried is what is got from the side of Tregonnin Hill, where there are several pits of it. As the stone hath a pretty large quantity of Caulin in it, so the Caulin hath a large mixture of the same sort of gravel as enters into the composition of the stone. It contains, besides, mica in abundance.