LEAD. BERZELIUS. 75 



oxide. Philos. Transact. 1814; I quote from Becker (*) p. 

 71. In this work Berzelius was assisted by F. H. Wollaston. 



Per unit of weight of lead carbonate, the above analysis 

 gives 0.835 as t* 16 analytical ratio. 



By our standard atomic weights, Pb Oa C =. 267 and 

 PbO 223, hence our atomic ratio is 



223 : 267 = 0.83 521 

 and rep' jting the calculation for Pb = 207. i we find 



223.1 : 267.1=0.83 527 



which is 6 higher. Hence, in our manner of expression, 

 "Change 6 high " for a rise of o.i in the atomic weight of 

 lead. 



With these standard ratios the actual analytical work has 

 to be compared. 



It will be seen, that every digit of the analytical ratio of 

 Berzelius is exact; it is 0.835. An( * this dates back to 1814! 



We find a second double determination in Meyer and 

 Seubert, p. 128; the individual values are never quoted by 

 M. & S., they only give aggregates. We can, however, trace 

 the exact value of the analytical ratio. 



The two determinations were made by Berzelius in 1817. 

 He took 10 grammes of carbonate in each determination ; 

 the sum of lead oxide stated is 16.6666 grammes. 



It is also stated, that the carbonate was found to contain 

 a trace of moisture ; 0.0225 in the first, 0.022 in the second, 

 hence 0.0445 in the two. Accordingly, the actual amount of 

 real lead carbonate was not 20 grammes exactly, but only 



19-9555- 



Dividing the amount of lead oxide, 16.6666 by the amount 

 of lead carbonate 19.9555 we obtain 0.83 517 as the analytical 

 ratio of Berzelius two analyses of 1817. 



It was with astonishment that I beheld this number; I 

 revised my calculation, being unprepared for such wonder- 

 ful result. 



*The so-called Recalculators, mainly of the work of Stas, but also 

 of all existing atomic weight determinations, are: 



Becker, Meyer and Seubert, Sebelien, Clarke, Ostwald, Van der 

 Plaats, and Julius Thomsen. The full title of their works will be given 

 at some one place. See True Atomic Weights, 1894, pp. 40-69. 



