Mineralogy and Geology. 123 



potash 0-74, water 14-33=99-64. Hence this mineral differs from 

 stilbite only in the proportion of water, and it falls into the group of 

 zeolites having the proportions 



rO:AI 2 3 :Si0 3 :: 1 :3: 12. 

 The following table exhibits their relations, 



rO Als 03 SiCM HO 



Stilbite, 1 : 3 : 12 6 in which rO=CaO 



Harmotome, 1 : 3 : 12 6 " rO=BaO 

 Heulandite, 1 : 3 : 12 5 " rO=(CaO, NaO, KO) 

 Epistilbite, 1 : 3 : 12 5 " rO=(CaO, NaO) 

 Brewsterite? 1 : 3 : 12 5 " rO=(SrO, BaO) 

 Edelforsite, 1 : 3 : 12 4 " rO=CaO 



12. On the identity of Osmelite and Pectolite, (Annuaire de Chem., 

 1848, p. 166.) — An analysis by M. Adam indicates that osmelite of Brei- 

 thaupt is identical with Kobell's pectolite. He obtained for it, silica 

 52-91, lime 32-96, protoxyd of manganese 1*44, soda 6'10, potash 279, 

 alumina and oxyd of iron 0-54, water 4-01. 



13. On Disterrite, from the valley of Fassa in Tyrol; by M. von 

 Kobell, (Jour. f. Prakt. Ch., xli, 154; Annuaire de Ch., 1848, 173.) 

 lJisterrite crystallizes in hexagonal prisms, cleaving parallel to the base, 

 and has a pearly luster on the terminal faces, with a vitreous luster on 

 the sides of the prism. H.=5 to 6£ (Breithaupt's scale). Density 

 3-042 — 3-051. Composition, silica 2000, alumina 43-22, peroxyd of 

 iron 3-60, magnesia 2501, lime 4*00, potash 0-57, water 3-60. 



14. On Glaucophane ; by M. Hausmann, (Jour. f. Prakt. Ch., xxxiv, 

 238; Annuaire de Chimie, 1846, p. 271.) — Glaucophane comes from 

 the island of the Cyclades, and resembles indicolite. It has a prismaiic 

 foliated structure, a clear blue color seen by refraction. Density 3-103 



3-113. Powder feebly attracted by the needle. The mean result of 

 two analyses is as follows :— silica 56-49, alumina 12-23, protoxyd of 

 iron 10-91, protoxyd of manganese 0-50, magnesia 797, lime 225, 

 soda with traces of potash 9-28=99-63. It is near Wichtyne from 

 Finland in composition. 



15. On Chloriioid* (Jour, fur Prakt. Ch., xxxiv, 454.)— MM. Erd- 

 mand and Gerathewohl have obtained for Chloritoid or Chloritic spar 



the formula Fe 3 Al-f-2Al Si after the following analyses. 

 Silica, 24-40 24931 



Protoxyd of iron, 30 29 30 047 



Alumina, 45-17=99-86, Ger, 45-016=99 994, Erd. 



16. On Humile.— Humite, according to Marignac's investigations, is 

 wentical with Chondrodite. 



17. On Epidote, (Jour, de Pharm. et de Chim., xiv, 3d ser., Sept., 

 1848, p. 214.)_M. Gerhardt here cites the analyses of M. Hermann 

 (Journ. f. Prafc,. Chem., xliii, 35 and 81,) of the different varieties of 

 ^pidote, including Zoisile and Pistacite of different localities, Bucklan- 



Q,r e, and Orthite or ceriferous Epidote. Hermann deduces from his 



Mr. J. d. Wliitney has tumid M mite to agree with Bonsdorff'fi analysis of 

 - — itoid, according to which this mineral contains 5 to 6 per cent, of water. His 

 parches are published in the Proc. Boat Nat. Hist. Soc., April, 1849, p. 100, and 

 W1U be cited in our next number. 



