[116] Since the first edition of this work was printed, the mineral has been found at Saint Michael's Mount, and, by Dr. Boase, amongst a pile of ore which was supposed to come from Botallack.
[117] In one of which is to be seen the Muriate of Tin, as first noticed by the late Reverend William Gregor.
[118] The following are the names of the respectable dealers to whom we recommend the mineralogist to apply,—At Truro, Tregoning, Mudge, and Heard;—at Redruth, Bennett; at Gwenap, Michell;—at Saint Agnes, Argall;—at Falmouth, Trathan;—and at Penzance, Jacobs, the latter of whom has generally a great variety of Saint Just minerals on sale.
[119] Opie was a parish apprentice to a person of the name of Wheeler, a house carpenter, in the village of Saint Agnes; Dr. Walcott, better known by his poetical appellation of Peter Pindar, having been struck, during his occasional visits to the village, by some rude sketches in chalk which were shewn him as the productions of this poor lad, invited him to his house at Truro, supplied him with the necessary materials, and enabled him to set up as an itinerant portrait painter, from which station he rose to be Professor of Painting to the Royal Academy.
[120] A highly interesting paper "On the decomposition of the Granite Tors of Cornwall," by this geologist, is published in the second volume of the Transactions of the Geological Society of London.
[121] This may be distinctly seen in the granitic rocks in the islands of Scilly; and in the Gritstone in the park of the late Sir Joseph Banks, in the parish of Ashover in Derbyshire.
[122] The only chemical difference between Cleavelandite and Felspar is, that about 12 per cent. of Potass in the latter is replaced by an equal quantity of Soda in the former. The earthy ingredients in both minerals are the same, and exist in similar proportions. The primary form of each is a doubly oblique prism, but the two prisms differ so essentially from each other in the measurement of their angles, that the substances are easily distinguished from each other by the Goniometer.