49 6 CALC GENUS. Obfervations. 1. Brochant remarks, that the Wernerian defcrip- tion of calc-fpar is not fufficiently minute, and there fore he finds it necelfary to fubjoin the cryftalome- trical obfervations of Hauy. However amufing the minute meafurements of Hauy may be, they are of little or no ufe to the oryftognoft, they cannot there fore find a place in this work. The preceding de- fcription of calc fpar, which I have drawn up accord ing to the Wernerian method, will enable us not only to diltinguifh calc fpar from all other foffris, but to know its mod remarkable varieties. 2. Brochant informs us that the fine rhomboidal calc fpar of Iceland is obtained by fplitting double fix Tided pyramids. 3. The rhomboidal calc fpar of Fontainbleau differs from the common varieties, by having an intermix* ture of fandy particles. third