CHUN CASTLE, a prominent object in this neighbourhood, is similar to _Caerbran Round_, which has been described, except that the ruins are more extensive, and less confused. The remains occupy the whole area of a hill commanding a wide tract of country to the east, some low grounds to the north and south, and the wide expanded ocean to the west. Another Cromlech may also be seen from this spot, and stands upon the very line which divides the parishes of Morvah and Saint Just; but it is far inferior to that at Lanyon. We will now for awhile abandon the contemplation of these faded monuments of past ages, and proceed to the examination of a rich and interesting field of mineralogical and geological research. In introducing the stranger, however, to the district of Saint Just, we must repeat to him the caution with which Mr. Carne[54] has very prudently accompanied his history of its mineral productions. "If the stranger on his arrival shall expect to find any of the minerals so prominently situated as to salute his eyes at once; or if he shall suppose that those objects which are especially worthy of notice in a geological point of view, are to be discovered and examined in the space of a few hours, he will be greatly mistaken and disappointed; for very few, either of the minerals or the veins are to be found _in situ_, except by a diligent, patient, and persevering search." Without further delay we shall now attend the traveller to _Pendeen Cove_; in our road to which, the only objects worthy attention are the Stamping Mills, and Burning Houses or Roasting Furnaces, belonging to _Botallack Mine_. They are situated on the bank of the river which runs into the sea at _Pendeen Cove_. The Tin ore of _Botallack_ is generally mixed with a portion of _Sulphuret of Copper_, which not being separable from it by the mechanical process of dressing, is submitted to the action of a roasting furnace, by which the Copper being converted into an oxide, and the Sulphur into Sulphuric acid, _a Sulphate of Copper_ is thus produced, which is easily separated by washing. The solution obtained is then poured into casks, containing pieces of iron, by the agency of which the _Copper_ is _precipitated_.[55] There is to be seen at _Pendeen_, a cave, known by the name of _Pendeen Vau_, and concerning which there are many ridiculous stories. It appears to have been one of those hiding places in which the Britons secreted themselves, and their property, from the attacks of the Saxons and Danes. The cave is still almost entire, a circumstance which is principally owing to the superstitious fears of the inhabitants, many of whom, at this very day, entertain a dread of entering it.