Record of Geology of Texas, \SS1-IS9Q. 
137 
Hidden, William Earl, and Mackintosh, J. B. 
yttria eartihs (A, B, 0, iD), wMcli were separated by successive precipita- 
tions with sodium sulphate. The atomic weight of each fraction was 
determined, showing successive increase, with each separation. The frac- 
tionation was discontinued after the fourth separation, as the amount of 
material was getting very small, but the atomic weight shows that tire 
lanthanum and didymium are still mixed with an earth of higher atomic 
weight. 
“The results obtained are as follows: 
SiO, 
29.17% 
Pb O 
0.854 
0.383 
TliOs 
12.00 
9.108 
Mn O 
0.77 
1.084 
Fe 0 
2.89 
4.014 
Ca O 
0.60 
1.071 
AI 3 O 3 
0.55 
1.6171 
Ce, G 3 
1.86 
1.722 
Atomic weight. 
(A) Ys O 3 
22.67= 
110.3 
25.320 
(B) Y 3 O 3 
5.30= 
110.53 
5.910' 
(C) Y, O 3 
4.50— 
114.9 
4.860 
(B) Y,03 
14.03- 
120 . 
14.616 
(La Di)o O 3 etc 
2.94= 
162. 
2.370 
UO 3 
0.83 
0.843, 
Ignition loss 
0.79 
99.754 
Oxygen ratio. 
97.234=4 
72.918=3 
Total yttria earths= 46.50% erbia spectrum distinct.' 
Analyses of Gradolinite by Ctenth* and Eakins.f Thoro-,Gummite, a 
Hydrated Uranium Thoro-silicate ; 
“This mineral, of which we have been able to gather about one kilo, 
occurs intimately associated with fergusonite and eyrtolite, and masses 
up to three ounces have been found, though for the most part it is in very 
small pieces, lit is of a dull yellowish-brown color, has hardness above 
that of gummite, or 4 — '4.5, and occurs commonly massive, though several 
well defined groups of zircon-shaped crystals have been discovered with 
angles near to those of zircon. It has a characteristic color, after Ignition, 
becoming of a dull greenish hue. (Thus it is distinguished from freyalite, 
eucrasite and thorite, which species it otherwise resembles in some respects. 
Its specific gravity varies from 4.43 to 4.54. It is easily soluble in nitric 
acid. The analytical results are: 
^Amer. Jour. iSci, II'I, Vol. XXXVTII, p. 200, Sept., 1889. 
fSee Eakins, L. G. (Gadolinite, Llano Co., Texas). Title 155. 
