$2 ABSOLUTE ATOMIC WEIGHT. 



The individual deviations of the analytical from the 

 atomic ratio are, in the order stated : 



1826: 3 low; 3 low; 9 low; 10 high. 



1830: 6 high; 3 high; 3 high; 6 high; 2 high. 



The earlier determinations fall almost equally on both 

 sides of the atomic ratio. 



The later determinations are all high: 2 high, once; 3 

 high, twice; 6 high, twice. 



Take the entire series, and the individual values of the 

 analytical ratios are identical in the first three decimals, 

 while the last two are, in the order of magnitude 



16, once; 22, twice; 28, twice; 31, thrice; 35, once. 



They are properly distributed about the mean value (27) 

 to allow the calculation of the probable error of the mean. 



This probable error is 1.4 in the 5th place. 



Surely, the atomic ratio is established as the true ratio by 

 these analytical ratios. 



These determinations of Berzelius leave no possible room 

 for the supposition that the deviation of the atomic weight 

 of lead from the standard 207 is anything but zero. 



Hence, these determinations of Berzelius demonstrate 

 that the true atomic weight of lead is 207 exactly. 



But why has this fact not been recognized, since these 

 experimental determinations of Berzelius have been known 

 for three quarters of a century? 



Very simply, because chemists, even Berzelius himself 

 not excepted, took each individual determination and from 

 it calculated the atomic weight of lead far beyond the 

 degree of precision warranted. 



It is well known that even Berzelius himself carried these 

 calculations, for his large unit of oxygen =. 100, to two or 

 three decimals. 



For lead 207 this gives 1293.75 in Berzelius' units. 



His own calculations, as reported by Sebelien (p. 146) 

 from these determinations ran from 1292.000 to 1294.946, a 

 range of 2.946. 



Now Berzelius must have had frequent occasions to notice 



