ATOMIC WEIGHTS 



531 



Brauner/ in a single experiment, found 0.88884Gd.,O3=: 1.4825? 

 Gd2(SOj3 = 1.83903 Gd,(SO,)3.8H,0. Per cent. Gd,03 in hydrous 

 sulphate, 48.332; in anhydrous salt, 59.951. Hence Gd = 155.725 and 

 155.78. 



The material studied by Brauner was received from Cleve, and was 

 not perfectly pure. The atomic weiglit found is too low. In combining 

 the figures for the percentage of GdoOg in Gd2(S0.j):;, Brauner's de- 

 termination may be given equal weight with tliat of Marc. We have 

 then — 



Bettendorff 60.080, ± .0013 



Benedicks 60.050, ± .0020 



Marc 60.032, ± .0120 



Brauner 59.951, ± .0120 



General mean 60.070, ± .0011 



The purest gadolinium preparations were probably those studied by 

 Urbain," who calcined the octohydrated sulphate to oxide. Two series 

 of determinations are given, representing different groups of fractions 

 obtained in the purification of his material. The data are as follows : 



Gd.i80,),.SH.O. 

 1.9256 

 1.9749 

 1.9975 

 2.1083 

 1.8993 

 2.2065 

 1.9535 

 2.2008 

 2.2482 

 2.1932 



Series I. 



Gd.O,. 



.9350 



.9589 



.9698 



1.0231 



.9214 



1.0707 



.9479 



1.0685 



1.0914 



1.0646 ■ 



Per cent. Gd.O-^ 

 48.557 

 48.555 

 48.551 

 48.528 

 48.514 

 48.525 

 48.524 

 48.551 

 48.546 

 48.541 



Mean, 48.543, ± .0077 



1 Abeg-g's Handbuch, Bd. 3, Abth. 1, p. 304. 

 -Compt. Kend., 140, 583. 1905. 



