48 REPORT — 1839. 



The differences on account of the oxide are the most considerable ; 

 next those on account of the sulphate ; and the differences on both of 

 these accounts are ten times greater than what arises from the experi- 

 ments on the nitrate alone. Thus, in such researches, do errors cu- 

 mulate. 



On reviewing the atomic weights thus ascertained, together with their 

 variations, there appear to me to be considerations entitling us to reject 

 some of the highest. 



First, as to azote. A^ has been found as high as 178*03. But ad- 

 mitting the atmosphere to consist of 21 bulks of oxygen for 79 bulks 

 of azote, we are quite sure that A^ cannot be so much as 177* ; for 

 then the specific gravity of oxygen must be less than 1*100, which 

 would contradict all good experiments on the subject that have been 

 made. Therefore 177* and any number higher must be rejected as too 

 much for A^. 



Next as to lead. By calculating from 1295*27, the greatest atomic 

 weight of lead, we obtain for A^, 178*03, 177*51, 176*99. But as even 

 this last and smallest number has been shown to be too high for azote, 

 so must 1295*27 be too high for lead. The next lower number found 

 by Berzelius was 1294*52, which affords, 



A"-Os A2 



Greatest 777*58 177*58 



Mean 777*06 177*06 



Least 776*54 1 76*54 



But this mean and this greatest are evidently too high, for the 

 reason already mentioned. Even the smallest number (176*54 for A^) 

 corresponds with a specific gravity for oxygen of 1*1021, which is 

 below the received experimental results. Therefore I apprehend we 

 are entitled to reject the second as well as the highest of Berzelius's 

 experimental results for the atomic weight of lead. His remaining ex- 

 periments are four : 



1. 1293*775 



2. 1292*647 



4. 1292*795 



5. 1293*888 



Mean 1293*276 

 Say, 



Highest 1293*89 

 Mean 1293*27 

 Least 1292*65 

 Repeating the calculations on this basis, we have. 



Greatest, Mean. Least. 



On lead one atom 1293*89 1293*27 1292*65 



Increase. 



r Greatest 600*77 600*48 600*19 



S'O^^ Mean 600*38 600*09 599*80 



[Least 600*03 599*74 599*45 



