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



lute values are converging to zero along each of the lines of work 

 pursued in the eighty years by the different chemists ; there is but one 

 insignificant exception, which we shall consider, when we take up 

 the recent work of Prandtl. 



Our Figs. I and 2 proclaim that the atomic weight of vanadium 

 is exactly 51 in all these determinations, just as sure as oxygen has 

 the atomic weight 16 exactly and silver 108 exactly, chlorine 35^ 

 exactly, sodium 23 exactly ; in fact, all the elements have as atomic 

 weights exactly the absolute values given in our publications of the 

 last twenty years. 



Even the very first determinations made by Berzelius, with only 

 a fraction of a gramme of material at service, and only in one single 

 determination, by the reactions designated (a), (b) and (c), do 

 confirm the value Va 51 ; for the deviation noted for \'a affects all 

 the other elements present as well, and therefore it would be absurd 

 to suppose that the atomic weight of vanadium could be obtained 

 from a reaction which fails to give an exact determination for the 

 other elements present. Thus reaction (c) represented by line D in 

 Fig. I, gives by the single determination made by Berzelius on 8 

 decigrams of the rather complex hydrated vanadium sulphate, a 

 departure of 400 thousandths from 51 for the atomic w^eight of 

 vanadium ; but the same determination gave the atomic weight of 

 oxvgen 310 thousandths low as marked on the figure; it also gave 

 the atomic weight of sulphur 470 thousandths low as indicated near 

 the edge of the diagram and by the arrowpoint : for the real circular 

 mark falls far beyond the limit of the diagram. 



Is it so hard to understand that a reaction that fails to give pre- 

 cise determinations for all the elements it involves cannot necessarily 

 be expected to furnish a value of precision for vanadium? Is it not 

 about time for each individual chemist to begin to consider these 

 simple facts for himself, as was the practice in former days? 



It would be interesting to trace the gradual approach to the center 

 where all departures are zero, as exemplified in the actual work of 

 the successive chemists. This will be found to hold good for all, 

 with the single exception alread\' mentioned. We will only point 

 to a few special instances, expecting the reader to go over the entire 

 ground bv himself. 



