COLUMBIUM. 71 



nia ; but this must be left for future investiga- 



tion. 



7. Berzelius precipitated nitrate of lead by 

 means of bitungstate of ammonia, and obtained 

 a tungstate of lead composed of 



Tungstic acid 

 Protoxide of lead 



48-866 



It was obviously a bitungstate, and quite differ- 

 ent from that which I obtained from tungstate of 

 soda by means of nitrate of lead. 



It is evident from this, that it would be hazard- 

 ous to attempt the analysis of tungstates by means 

 of nitrate of lead : the precipitate might be either 

 a tungstate or bitungstate of lead ; and most fre- 

 quently it would be a mixture of both. 



SECT. VI. 



OF THE ATOMIC WEIGHT OF COLUMBIUM. 



THIS metal was discovered in 1801, by Mr, 

 Hatchett, in a black mineral in the British Mu- 

 seum, which had been sent by Dr. Winthorp to 

 Sir Hans Sloane, from Massachussets in North 

 America. Mr. Hatchett found the constituents 

 of this mineral to be about 



