192 HINRICHS— ATOMIC WEIGHT OF VANADIUM. [April 21, 



which, as a good Scandinavian, he named vanadin after \"anadiis, 

 a designation of Freya, the greatest Goddess in \'alhalla. 



Sefstrom had promptly informed his teacher of the discovery 

 and soon after brought his entire stock of the new element to 

 Berzelius, requesting him to continue the research for which his 

 own industrial work and the professorial duties at the Fahlun 

 JVIontan-School left him neither the leisure nor the facilities. For 

 a short time Sefstrom worked with Berzelius on the new element in 

 that famous " Kitchen Laboratory " where Berzelius alone com- 

 pleted the splendid work of which he published a summary on pp. 

 99-110 of the "Annual Report" which he presented to the Swedish 

 Academy of Sciences on March 31, 1831 — exactly eighty years ago. 



For almost forty years the element vanadin of Sefstrom and 

 Berzelius remained undecomposed, but the striking isomorphism 

 of the mineral vanadinite with the remarkable isomorphic group of 

 apatite and pyromorphite presented the anomalous condition of the 

 isomorphism of the element vanadin of Berzelius with the group 

 PO of apatite and pyromorphite. This anomaly invited further 

 attempts of the reduction of vanadin in which Roscoe was success- 

 ful, 1867, proving vanadin to be really the oxide A'aO, in which Va 

 is the symbol of the present element vanadium of the atomic weight 

 51. This fully explains the isomorphism of vanadinite containing 

 the oxide VaO, with pyromorphite, containing the corresponding 

 oxide PO. 



In this first research of Berzelius on vanadium, the old master 

 already determined the atomic weight of the new element ; for 

 his value 67 for what we now know to have been VaO gives Va 51. 

 He devised and used five distinct chemical methods for this atomic 

 weight determination to which npt one new method has been added 

 in the eighty years elapsed since that work was done by the great 

 chemist in his kitchen laboratory. It is a well-authenticated historic 

 fact, Berzelius not only made atomic weight determinations for 

 vanadium, but they were as accurate as those made forty years 

 later by Roscoe, while some were as precise as corresponding 

 determinations made eighty years later by Prandtl ; besides, not only 

 Roscoe and Prandtl, but all chemists have done this work bv means 



