76 THE ATOMIC WKIGOTS. 



r.. 



159.970 

 159.964 



159-959 

 159.965 



Mean, 159.9645, i .0015 

 Mean from lioth .series, 159.9704, ± .0010 



There still remain to be noticed two sets of experiments 

 upon lead nitrate, which were originally intended to estab- 

 lisli the atomic weight of nitrogen. Lead nitrate was care- 

 fully ignited and the residual oxide weighed. The first 

 series, bearing Svanberg's name,* gives simply the percent- 

 age of oxide found, as follows : 



67.4030 

 67.4036 

 67.4043 

 67-5956 



Mean, 67.4016, zh .0014 



The second series is by Anderson,t and gives the weigh- 

 ings upon Avhich the percentages rest. The latter come out 

 thus : 



5.19485 grm. PbN/Jg gave 3.5017 grm. PbO. 67.4071 percent. 



9.7244 " 6.5546 " 67.4037 



9.2181 " 6.2134 " 67.4044 " 



9.6530 " 6.5057 " 67.3957 " 



Mean, 67.4027, rt .0016 



It will at once be seen that these series are identical ; the 

 discordance between the first figures of the two being un- 

 doubtedly due to some misprint in the weighings of the 

 Anderson set. How it hapjiens that the same work has 

 been published by two separate authors I will not attempt 

 to explain ; neither will I undertake to determine whicli of 

 the two is really entitled to credit. 



*Journ. fiir Prakt. Chem.,27, 381. 1S42. 

 f Ann. Chim. Pliys., (3,) 9, 254. 1843. 



