OF THE JEFFERSONITE. 199 



Silex . . . o. 560 containing oxygen 29. M700 29 



Lime . o. 151 4.24159 4 



Protoxide of Manganese 0. 135 . . . 2.95790 3 



Peroxide of Iron 0. 100 - . . 3.06600 3 



Oxide of Zinc 



0. 010 



Alumine 



0. 020 



Loss by calcination 



0. 010 



0. 986 

 Loss 0. 014 



1. 000 



By assuming the mineralogical formula 4 CS*+ 

 S?ngS 3 -j-2FS :i , which is very nearly that indicated by 



alkalies added. The precipitate by the hydro-sulfate, which 

 consisted of the oxides of iron, manganese, and zinc, with alu- 

 mine, was then calcined and weighed, after which it was re-dis- 

 solved in nitro-muriatic acid, (the alumine being in very small 

 quantity was also re-dissolved.) A saturated carbonate of soda, 

 added without excess, precipitated the oxide of iron, leaving 

 those of manganese and zinc. On examining the iron, it was 

 found to have carried down with it the alumine which was rea- 

 dily separated. The oxides of manganese and zinc were then 

 precipitated by sub-carbonate of soda, and separated by means 

 of ammonia, according to the accurate method recommended by 

 Mr. Berzelius, and described by Mr. Berthier in the " Annales 

 des Mines." 



The loss by calcination was ascertained by heating it to a white 

 heat in a platina crucible, during a quarter of an hour. The co- 

 lour of the mineral was slightly altered, it became of a browner 

 hue, and lost one per cent. 



The powder was not magnetic, either before or after calcina- 

 tion. 



