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



The chemist whose work is represented is indicated by the special 

 mark used to designate the point, as shown in the explanation of 

 signs on the diagram. 



The small figure near the vanadium sign on the vertical indicates 

 the number of determinations made represented in that line. 



The line itself is marked by a letter, used in the tables for the 

 purpose of ready identification. 



For each reaction, the geometrical place (or locus) is a straight 

 line passing through the center or the origin ; the angle under which 

 it cuts the axes is determined by the ratio of the variation of the 

 element concerned and that of vanadium. These lines can therefore 

 be drawn before any laboratory work is done, depending entirely on 

 the chemical formulas of the compounds taken and obtained in the 

 reaction used. 



For further particulars, some of which are very interesting as 

 well as useful, we may refer to page 60 of our " Cinquantenaire," 

 where also a remarkable criterion is given, permitting to detect any 

 error in the assumed absolute atomic weight. The example there 

 taken is copper. 



Our two figures here inserted bring into clearest possible view^ the 

 fundamental fact that all these departures are co-related ; that the 

 experimental error is not thrown on the vanadium for which the 

 atomic weight is sought, but is distributed ex-aec|uo to all elements 

 partaking in the reaction, as we have shown in formulae, but which 

 is here presented to the eye directly. 



We do not recognize or find the slightest pretext for the assump- 

 tion that any one element is immaculate and cannot be conceived to 

 partake in any error of whatever cause or origin ; but we have found 

 that all elements in a chemical reaction are afl:'ected by the same 

 cause of error according to the ties that bind them and which we 

 have read in the chemical formula and in the mathematical relations 

 first studied by Lagrange under the name of the \'ariation of arbi- 

 trary constants. ^- 



We know that it is absurd to suppose that oxygen is always found 

 to be 16, absolutely unaffected by any error, physical or chemical, in 

 practice ; that next some other atomic weight of some other element 



""True Atomic Weights," 1894, p. 158. 



