54 Chemical Examination of American Minerals. 



united together. But it is impossible to say how much oi 

 each is necessary to constitute the mineral, as the proportions 

 of magnesia and peroxide of iron vary in the two varieties 

 analyzed. Paulite consists of about 3 atoms bisilicate of 

 magnesia, and 1 atom of iron ; while Isle of Skye hypersthene 

 contains 2 atoms bisilicate of magnesia, and 3 atoms bisilicate 

 of iron. It is obvious that the magnesia and peroxide of 

 iron are capable of replacing each other in this mineral. 

 We may exhibit the composition of hypersthene in general, 

 by the formula a;M?iS- + j/FS'. X and y denoting the un- 

 known number of atoms of the two bisilicates. 



18. CHONDRODITE. 



This mineral was first described, analyzed and named by 

 Count D'Ohsson, in the Kongl. Vetenskaps Acad. Handlingar. 

 for 1817, p. 206. The specimen was from Pargas, in Fin- 

 land, and the name chondroflite, (from j^ovd^w^yj^ granular) 

 was given to the mineral because it occurred in the specimen 

 in the state of grains. The same mineral had been previously 

 observed by Dr. Bruce, at Newton, Sussex County, New- 

 Jersey, in small rhomboidal prisms imbedded in calcareous 

 spar, but mistaken by him for an ore of titanium. In 1823, 

 an analysis of it by Mr. Seybert, was read before the Ameri- 

 can Philosophical Society, and published in the 5th volume 

 of Silliman's Journal. Seybert discovered in it the presence 

 of fluoric acid, which had escaped Berzelius in two separate 

 analyses which he made of this mineral. This led him to 

 consider it as a new mineral, and to di>tinguish it by the 

 name of Maclurite, as a tribute of respect to Mr. Maclure, 

 the celebrated American geologist. Some of the American 

 mineralogists had given it the name of Brucite. 



About two years ago, I received from Dr. Torrey some 

 very fine specimens of what he called massive chondrodite 

 from a new locality ; namely, Eden, Orange County, New- 



