ATOMIC WEIGHTS 523 



One determination, by Boudouard/ was made by calcination of the 

 sulphate. 2.758 grammes of Nd„(SOJ, gave l.fi05 of NdoOg, or 58.194 

 per cent. Hence Nd = 143.18. 



Brill/ in 1905, made two analyses of neodymium sulphate, with the 

 aid of the microbalance. His percentages of NdoO., are 



58.000 

 58.180 



Mean, 58.090, ± .0600 



Hence Nd = 142.46. 



In Abegg's Handbuch, Brauner ' gives the details of a synthesis of 

 neodymium sulphate, with corrections for excess of acid. 0.93788 

 gramme Nd^Oj gave 1.60873 Nd„(S04)3. Per cent. l^d.,0,„ 58.299, 

 whence Nd = 143.90. 



Holmberg,* who employed the usual synthetic method, found no serious 

 difficulty in obtaining a neutral sulphate. In his series of determina- 

 tions, therefore, a correction for excess of sulphuric acid was not needed. 

 His six svntheses are as follows: 



Mean. .58.327, ± .0019 



Hence Nd = 144.10. 



In combining these various determinations of the oxide-sulphate ratio, 

 the single experiments by Boudouard and Brauner are each given the 

 probable error of one experiment in .Tones' series: 



Jones 58.246, ± .0015 



Boudouard 58.194, ± .0067 



Brill 58.090, ±: .0600 



Brauner 58.299, ±: .0067 



Holmberg 58.327, ± .0019 



General mean 58.2831, ±: .0011 



1 Compt. Kend., 126, 900. 1898. 



- Zeitsch. .nnorg. Cheni., 47, 464. 19t;5. 



^ .^begg's Handbuch, Bd. 3, Abth. 1. p. 270. Pieliminan- note in Proc. Chein. Soc, 17, 66. 1901. 



•* Zeitsch. ancrg. Chem., 5.3. 124. 1907. 



