In the collection of Joseph Carne, Esq. at Penzance, may be seen _prehnite_ in a variety of forms, _axinite_ in its usual form, _stilbite_ in flat four-sided prisms terminated by pyramids, _mesotype_ radiated, _garnets_ in 12 and 24 sided, crystals, _pirite_ in six and 12 sided prisms, _uranite_ in quadrangular tables with the angles in some cases truncated, and also in forms much resembling cubes and octohedrons, _uranochre_, _native bismuth_, and _specular iron_ ore, very simular to that found at Elba; _grey sulphuret_ of _copper_, the best defined crystals of which are very obtuse dodecahedrons, and six-sided prisms; in some specimens the dodecahedrons are so placed upon the summit of the prisms, as to resemble a nail: this is one of the most rare specimens ever found in Cornwall, and is much sought after by mineralogists. Here are also two very rare and curious specimens of _yellow_ and _grey sulphuret of copper_, in forms resembling a cube, the latter being pseudomorphous. The Royal Geological Society at Penzance possessed many valuable and rare specimens; among the earthy species may be enumerated, _calcedony_, _sodalite_, _haiiyne_, _petalite_, _colophonite_, _vesuvian_, &c. In the metallic branch, is _carbonate of lead_, _specular iron_, _arseniate of iron_, the _oxide_, _carbonate_, _arseniate_ and _phosphate of copper_, _native gold_, found in the Cornish Tin Stream Works; _arsenical pyrites_, _uranite_, _uran ochre_, _native nickel_, &c. besides a mineral but little known, viz. _subcarburet_ of iron, and which was analyzed by the late Rev. W. Gregor. The cabinet of John Williams, Esq. at Scorrier House, near Redruth, is unrivalled in its specimens of _red oxide of copper_ in _octohedrons_, cubes, and capillary crystals; there are also some fine specimens of _arseniate_ of copper in very perfect obtuse octohedrons; a mass of uranite, which for size and beauty surpasses any that has ever been found: _blende_ in octohedrons and cubes, _native_ and ruby silver, besides a very rare and highly valuable specimen of the muriate of _horn silver_ and _arseniate of lead_ in six-sided prisms. Such strangers as are desirous of forming a collection of the several minerals which have been found in this county, cannot adopt a better plan than applying to the different dealers; they are, however, sometimes to be had of the miners. The most respectable dealers in minerals are, at St. Austell, Mr. Hennah, Bookseller; at Truro, Tregoning and Mudge; at Falmouth, Mr. Trathan; at Penzance, Mr. Jacobs; at Redruth, Mr. Bennett; at Gwenap, Mr. Michell; at St. Agnes, Mr. Argall; and the landlord of the Tamar Inn, Calstock; who was once a superintendant of some of the mines near St. Austell. ------------------------------------------------------------------------ EXCURSION TO THE SCILLY ISLANDS.