called the Gadolinite. 3/1 



without diftinction, all the elements which compofe this 

 done, a hydro-fulphuret muft be employed to feparate the 

 metals; and the juft management of this operation is diffi- 

 cult, becaufe the new earth is precipitated by an excefs of 

 the re- agent. 



By the help of thofe means, which I have briefly explained, 

 I was able to difcover and feparate the fubftances which 

 enter into the compofition of the ftone called gadolinite. 

 Thefe fubftances arc filex, black oxyd of iron, lime, oxyd of 

 manganefe, and the peculiar earth to which M. Ekeberg 

 has given the name of Yttria. 



The proportions in which they are found are as follow : 

 i ft, Silex — — 25-5 



3d, Oxvd of iron — 25 



3d, Oxyd of manganefe — 2 



4th, Lime — — 2 



5th, The new earth, or Yttria 35 



89'5 

 Lofs jo '5 



Thefe io*5 form the fmalleft lofs I experienced in the dif- 

 ferent analyfes I made; for I thought it necelTary to employ, 

 in conftruc-ling this table, the greateft quantities of each of 

 the matters obtained by either of the proeefles. 



I at firft thought that this lofs arofe from fome alkaline 

 fubftances, as is the cafe in feveral kinds of ftone ; but, hav- 

 ing treated too parts by fulphuric acid, I allured mvfelf that 

 it arofe from another caufe; for, having precipitated by am- 

 monia all tliu earthy and metallic matters diflblvecl in the 

 fulphuric acid, and having brought to a red heat the fait 

 produced by evaporating the liquor to drynefs, there remained 

 nothing in the crucible but a little fulphat of lime. 



As I fufpected that this was occasioned by fome volatile 

 ■fubftance, I heated, in a platina crucible, 100 parts of the 

 ftone reduced to powder, and found that it had decreafed 

 eight parts, and that the remainder had alTumcd a yellowifh 

 colour. 



The flight effervefcence which I had always remarked 

 4 when 



