342 THE ATOMIC WEIGHTS. 



100 parts of Ce,(S0 4 ) 3 gave 123.30 of BaS0 4 . This may be assigned equal 

 weight with one experiment in Marignac's series, giving the following 

 combination : 



Hermann 123 926, .238 



Marignac 122.40, .138 



Schutzenherger 123.30, .238 



General mean ..................... 122.958, . 1 139 



Schutzenberger, criticising Brauner's work, claims that the latter was 

 affected by a loss of oxygen during the calcination of the cerium dioxide. 



In his second and third papers Schutzenberger describes the results 

 obtained upon the fractional crystallization of cerium sulphate. Prepa- 

 rations were thus made yielding oxides of various colors canary yellow, 

 rose, yellowish rose, reddish, and brownish red. These oxides, by syn- 

 thesis of sulphates, the barium-sulphate method, etc., gave varying values 

 for the atomic weight of cerium, ranging from 135.7 to 143.3. Schutzen- 

 berger therefore infers that cerium oxide from cerite contains small 

 quantities of another earth of lower molecular weight ; but the results as 

 given are not sufficiently detailed to be conclusive. The third paper is 

 essentially a continuation of the second, with reference to the didymiums. 



Schutzenberger's papers were promptly followed by one from Brauner,* 

 who claims priority in the matter of fractio nation, and gives some new 

 data, the latter tending to show that cerium oxide is a mixture of at least 

 two earths. One of these, of a dark salmon color, he ascribes to a new 

 element, " meta-cerium." The other he calls cerium, and gives for it a 

 preliminary atomic weight determination. The pure oxalate, by Gibbs y 

 method, gave 46.934 per cent, of Ce0 2 , and, on titration with potassium 

 permanganate, 29.503 and 29.506 per cent, of C 2 O 3 . Hence Ce = 138.799. 

 In mean, this ratio may be written 



3 C 2 3 : 2Ce0 2 : : 29.5045 : 46-934, 



and to each of its numerical terms we may roughly assign the probable 

 error .001. This is derived from the average of the two titrations, and 

 is altogether arbitrary. 



The ratios, good and bad, for cerium now are 



(i.) Ce 2 (SO 4 \ s : 3BaSO 4 : : 100 : 122.958, d= .1139 



(2.) 3BaSO 4 : 2CeO 2 : : 100 : 49-36o, .035 



(3.) 3 BaCl 2 : Ce 2 (S0 4 ) 3 : : loo : 91.625, .016 



(4.) 3AgCl : CeO 2 : : loo : 40.469, .0415 



(5.) Percentage CeO 2 from Ce 2 (SO 4 ) 3 , 60.566, .0021 



(6.) Percentage CeO 2 from Ce 2 (C 2 O 4 > ) 3 , 63.4316, + .0032 



(7.) Percentage CO 2 from Ce 2 (C 2 O 4 ) 3 , 48.2546, =b .001. 



(8.) 3Ag : CeCl 3 : : IOO : 76.167, .0065 



(9-) 3 C 2 3 : 2Ce 2 : : 2 9.5 45, .001 : 46.934, -ooi 



*Chem. News, 71, 283. 



