1326.] new Variety of Wolfram. 32^ 



men of tungstate of iron, in which he suspected the presence of 

 Xia and columbium. I could not find either of these bodies, 

 Lt I found the proportions of its elements different from those 

 previously determined to exist in wolfram by the chemists above 



^^ In "the first analysis, we obtained the following results : 



Peroxide of iron 16-0 



Peroxide of manganese 14-8 



consequently Tungstic acid ^^'^ 



100-0 



On examining the iron, we found that it still contained some 

 manganese, and the latter contained a little carbonate of lime. 

 In a second analysis, we had 



Peroxide of iron 15*6 



Peroxide of manganese 16-0 



consequently Tungstic acid ^^'^ 



100-0 

 Lastly, a third analysis gave, 



Peroxide of iron 13-8 



Peroxide of manganese Ijj'O 



consequently Tungstic acid 



73-2 



100-0 



There is, therefore, in this case a larger proportion of manga- 

 nese than in common wolfram ; but the question is, whether it 

 is actually a new variety, or if the diff"erence which occurs is 

 not dependent upon the less perfect methods then employed. It 

 is, therefore, requisite to state how 1 operated. 



1 I fuse the powdered mineral in a platina crucible, with one 

 and'a half its weight of caustic potash, adding a little water to 



facilitate their mixture. . c • i,- u 



2 When the matter is in a state of very perfect fusion, which 

 occurs readily, I put the whole into water, and keep it boiling^ 

 for some time to accelerate the precipitation of the oxides ot 

 iron and manganese. , , ^u 



3. 1 draw off the clear liquor by a syphon, and wash the resi- 

 duum with boiling water till it ceases to be alkaline. 



4 Then I dry the oxides at a red heat, and weigh them. 



5* 1 dissolve them in muriatic acid, dilute the solution with 

 wat'er, and add a little carbonate of potash, until the iron is per- 

 fectly separated, and the solution is colourless. 



6 I filter it through dried and weighed paper, and when it is 

 well washed, I heat it in a platina crucible ; but as a small quan- 

 tity always remains upon the filter, I dry it at a temperature of 



