Intelligence and Miscellaneous Articles. 73 



but that the carbon itself had thoroughly fused was obvious. The 

 mass formed a perfectly black glass, which, broken in pieces, showed 

 no traces of black powder in any of the interstices. 



I have manj' specimens of the mass in my possession ; but the re- 

 sult (as far as I know is new) is easily obtained by observing that the 

 silica is in the excess mentioned. 



Fluoric acid, or strong hot caustic potass, dissolve out the silica, 

 and the charcoal then falls in powder no way altered. With pow- 

 dered plumbago the result was the same. Your's obediently, 



Euston Hotel, October 1841. H. Prater. 



COMPOSITION OF WOLFRAM. 



M. Schaffgotsch, in analysing wolfram obtained from different 

 places, found that the sum of the ponderable quantities of the bases 

 was always greater than it should be in a neutral tungstate of iron 

 and manganese, and that the quantity of tungstic acid yielded by 

 analysis was constantly larger than that calculated according to the 

 composition generally admitted. This circumstance, supported by 

 direct analysis, led M. Schaffgotsch to the conclusion that wolfram 

 contains oxide of tungsten, and not tungstic acid. 



The analyses were performed in the following manner : — The finely 

 powdered mineral was fused with three times its weight of carbonate 

 of soda. After treating the fused mass with water, the two oxides of 

 iron and manganese which were left, were dissolved by hydrochloric 

 acid, and separated by means of ammonia and its succinate. The 

 tungsten exists in the solution as tungstic acid ; but as it is almost im- 

 possible to separate this acid perfectly from soda, or from its sulphur 

 salt, by acids, another method was sought. The wolfram was boiled 

 in hydrochloric acid ; the acid is to be repeatedly added, and the 

 ore cannot be considered as perfectly acted upon until the deposit is 

 of a very pure canary-yellow colour : this deposit is tungstic acid ; 

 it is to be collected on a filter, and the liquor, precipitated by excess 

 of ammonia and of hydrosulphate, is evaporated after filtration. The 

 residue roasted in the air yielded a small quantity of tungstic acid, 

 which had been dissolved by the hydrochloric acid. This process 

 succeeded without difficulty. 



Taking the mean of such analyses as were made more than once, 

 the following are the results of the mineral analysed from the places 

 named : — 



Monte Video. Ehrenfriedersdorf. Chanteloupe. Zinnwald. 



Protoxide of iron 1924 19-16 1795 954 



Protoxide of manganese. 4*97 4 "74 605 14"84 



Tungsten and oxygen . . 75-89 76-10 76-00 75-62 



100-10 100- 100- 100-^ 



The author remarks that tliese analyses warrant the following 

 conclusions : — 



1st. That wolfram is formed by two compounds: one of 1 atom 

 of protoxide of iron, Fc O, and of 1 atom of oxide of tungsten, WO- ; 



