Iron Pyrites

Sulphuret of Iron, figured so long since in cubes clubbed together (tab. 29,) is here represented, showing the manner of aggregation by nuclei into a cubo-octohedron, as it were done on purpose for instruction, and is very interesting to a novice, besides assisting him in the comprehension of the means of aggregation and symmetrical method that is displayed in the variety that accompanies it, which variety is of a whiter hue and differs but little else than in the number of facets, and which required the middle lower figure to explain it as derived from the same cube by nuclei so minute as to leave a finely polished surface; and when rounding in the facets, as in some parts of the specimen, still shows no irregularity or gaping. Thus the philosophy of nature is explained by her own actions, and the larger help to explain the smaller to our admiration, and the more so as we are allowed to improve in discernment, and what was formerly a sort of chaos, now becomes subjected to mathematical calculation.