William Phillips

“ The occasional notice of what appear to be perfect cubes, added to the certainty that cleavages are practicable parallel with every plane of that solid, at first tempted me to presume that it ought to be considered as the primitive form; but the consideration of some circumstances connected with the crystallization of this substance, induced me wholly to abandon the idea. The inspection of the annexed drawings will evince that, of the five modifications described, the first alone is compatible with the cube. ”

“ I also obtained many specimens containing beautiful and well defined crystals of the oxyd of uranium from Tol Carn mine, which is about two miles north of Carharack, and near St. Die. The veins of Tol Carn mine pass through a decomposed granite, of which the prevailing substance seems to be felspar, enclosing portions of quartz and silvery mica. With this substance the vein seems to have been filled in that part in which the oxyd of uranium was found, but it was of a dark colour, and had attained, though considerably friable, a texture much more firm than that of the neighbouring country ”

“ By this modification the terminal edges of the primitive prism are replaced by trapezoidal planes tending to form an octahedron, fig. 46. The succeeding figure shews the planes of this, in combination with those of the second modification, or the acute octahedron. The crystals described by figs. 46 and 47 are numerous, brilliant, and well defined: they rarely exhibit any lateral striæ, but are so minute as to render it impossible even to approximate the real admeasurement of the angles formed by the meeting of any two of their planes. ”