Chemical Examination of American Minerals. 35 



Phosphoric acid ----- 24 



Protoxide of iron, . - _ - - 42*65 



Water, 25-00 



Mixed grains of sand, - _ _ - 7*90 



99-55 



It seems to be a hydrous diphosphate of iron, composed of, 



1 atom phosphoric acid, _ - - - 4-5 



2 atoms protoxide of iron, - - - - 9 



4i atoms water, ----- 5-0625 



18-5625 



Or, if we suppose the half atom of water only mechanically 

 lodged in the interstices of the mineral, the atomic weight 

 will be 18. 



This mineral is obviously the same with the phosphated 

 iron from the Isle of Fiance, and from Brazil, analyzed many 

 years ago by Laugier and Cadet. Nor is there reason to 

 believe that the transparent crystals found in Cornwall, and 

 known by the name ofVivianite, constitute a distinct species. 

 They are all hydrous diphosphates of iron, having a right 

 oblique prism, with angles of 125=' 15' and 54° 45' for the 

 primary form. 



Note. This mineral is found in various parts of the tertiary 

 formation of New-Jersey. It frequently occurs in the form of 

 belemnites and bivalve shells. 



An account of it by Dr. J. Cutbush, appeared in the Ameri- 

 can MineralogicalJournal, Vol I. p. 86. Dr. Cutbush could 

 not detect any phosphoric acid in it ; but he states in a note, 

 that Mr. Godon found this ingredient in a specimen of the 

 ore which he examined. 



Professor Cooper afterwards gave a description and analy- 

 sis of the mineral in the first volume (new series) of the Ame- 



