354 THE ATOMIC WEIGHTS. 



SCANDIUM. 



Cleve,* who was the first to make accurate experiments on the atomic 

 weight of this metal, obtained tlie following data : 1.451 grm. of sulphate, 

 ignited, gave .5293 grm. of Sc.fi.^. .4479 grm. of ScjOj, converted into 

 sulphate, yielded 1.2255 grm. of the latter, which, upon ignition, gave 

 .4479 grm. of Sc^Oj. Hence, for the percentage of Sc^Oj in Sc.XSO^). we 

 have : 



36.478 



36.556 



36.556 



Mean, 36.530, ± .0175 



Hence, if SO3 = 79.465, Sc =-- 44.882. 



Later results are those of Nilson,t who converted scandium oxide into 

 the sulphate. I give in a third column the percentage of oxide in sul- 

 phate : 



•3379 grm. SCjOg gave .9343 grm. 802(80^)3. 36.166 per cent. 



.3015 " .8330 " 36.194 " 



.2998 " .8257 " 36.1S7 " 



.3192 " .8823 " 36.17S " 



Mean, 36.181, ifc .004 



Hence Sc = 43.758. 



Combining the two series, we have — 



Cleve 36.530, ± -0175 



Nilson 36. 181, =h .0040 



General mean 36.190, dz .0039 



Hence, with SO3 = 79.465, ± .00175, 



Sc = 43.784, =h .0085. 



If 0= 16, Sc = 44.118. 



As between the two values found, the presumption is in favor of the 

 lower. The most obvious source of error would be the presence in the 

 scandia of earths of higher molecular weight. 



* Compt. Rend., 89, 419. 

 fCompt. Rend., 91, 118. 



