130 



[Senate 



This gives: magnesia, 61 -67 ; water, 27*24; carbonic acid, 11-09; = 

 100. It effervesces sensibly in acids, and contains only a minute quan- 

 tity of silica. Proceed HLgs of the British Association^ for 1846. 



I cannot but think that the specimen analyzed by Prof. Connell must 

 have been impure. His formula is too complex. 



A more recent analysis of this mineral by Mr. J. D. Whitney, shows 

 it to be a fibrous variety of the hydrate of magnesia, or brucite. It 

 afforded him magnesia, 62*89; protoxide of iron, 4*65 ; carbonic acid, 

 4*10; water, 28*36. A small portion of magnesia is replaced by pro- 

 toxide of iron. The formula of brucite (Mg H) requires magnesia, 

 69-67 ; water, 30-33. Jour. Bost. Sac. Nat. Hist. 1849, p. 36, 



SEEPENTINE. 

 (Mineralogy of New- York, page 272.) 



Subsequent examination has satisfied me of the protean forms of this 

 mineral, and would lead me to receive with distrust the dermaiin and 

 kypkolite proposed by Breithaupt, and the hydrophite and picropkyll of 

 Svanberg. Marmolite should certainly be united with serpentine, and 

 the same may be said of a"l the minerals included under the general 

 name of magnesite. 



The supposed crystalline forms of this mineral, are, probably, in most 

 cases, pseudomorphs. Some of these have heretofore been noticed. 

 Kersten has examined a specimen of serpentine from Schwarzenberg, 

 which is remarkable, as being a pseudomorph in the crystalline form of 

 garnet. The crystals are blackish green, and contain a mixture of 82-50 

 of serpentine, and 17-50 magnetic iron ore, which can be separated by 

 the magnet. The serpentine w^as composed of silicic acid, 41*50; 

 magnesia, 40*34; protoxide of iron, 4*10; oxide of manganese, 0*50; 

 soda, 0*42; water, 12-87. Berzelius' Annual Report, 1847. 



Upon a comparison of specimens, I find that some of the varieties of 

 serpentine from Phillipstown, (Heustis' farm) in Putnam county, closely 

 resemble those from Smithfield, Rhode Island, and which are usually 

 labelled nephrite, 



CHONDRODITE. 



(Mineralogy of New- York, page 281.) 



Two new localities of this mineral are to be added to those hereto- 

 fore given. The one in Schroon. Essex county, and the other in Car- 

 mel, Putnam county. 



