igii.] 



HINRICHS— ATOMIC WEIGHT OF VANADIUM. 



201 



137^/^ ; H, 1.008 instead of the exact value 1.00781 determined 

 atomechanically by us (Rcvuc gen. dc Chiiiiic, 1910. p. 386). 



TABLE I. 



Fundamental Constants for Vanadium. 



269 

 270 

 3" 



O, 



VaOClj 



3Ag 

 VaOCla 



NaCl 



Va,05 

 2VaOCl3 



VaPs 



2B^S07 

 Va,0. 



Atomic Ratio, R. 



Fraction. 



Decimal.* 



0.17 582 I —19 

 0-53 549 31 



32 



182 

 173-5 

 324.0 



'73-5 



7— — f 0.40 302 



430.5 r ^ -^ 

 58.5 I 



122:^ °-47 951 



182 



347 

 182 



467 

 182.00 



Variation A for 



O. 



Va sulphate' 398.06 



0.52 450 



0.38 972 

 0.45 722 



-39 

 27 



43 

 27 



62 



31 



23 



— 118 



"3 



Ci. 



93 



42 



304 



91 



40 |- i7(S) 

 35 !— 23(S) 



Metal. 



-49 (Ag) 



-28(Ag) 



43(Na) 



-17 (Ba) 

 -140(H) 



II. — General Summary of the Experimental Work Done. 



In the common reviews of the experimental work done for 

 atomic weight determinations, the amount of substance taken in each 

 experiment is not made the subject of special consideration. This 

 neglect is due to the erroneous estimation in which the so-called 

 "probable error" of the mean is held. 



This probable error has caused the most serious errors in all 

 branches of physical science where it has been applied — in the un- 

 fortunately common way. without proper understanding. We have 

 treated of this repeatedly, especially in our " absolute atomic 

 weights, 1901. on the first hundred pages, to which we must refer. 



In the language of Berzelius already quoted we might say the 

 above probable error is the gnat strained at which hides from sight 

 the camel-like systematic and constant errors which are swallowed. 

 We have, at last, seen one admission of the fact we have always 



^ Between the second and third decimal of the five, we always leave a space 

 to make the constancy of the first two conspicuous. 



'The crystallized sulphate is [VaOJ^S^Os -f 4H=0. 



