No. 1 Glastonbury, Conn.No. 2 Johanngeorgenstadt, Saxony
Sp. Gr.9·596·89
UO326·4860·05
UO257·4322·33
ThO29·79...
CeO20·25...
La2O30·13...
Y2O30·20...
PbO3·266·39
CaO0·081·00
Heund.und.
H2O0·613·17
Fe2O30·400·21
SiO20·250·50
Al2O3...0·20
Bi2O3...0·75
CuO...0·17
MnO...0·09
MgO...0·17
Na2O...0·31
P2O5...0·06
SO3...0·19
As2O3...2·34
Insoluble0·70...

The following list comprises the more important radio-active minerals, with their approximate chemical composition and some notes on their occurrence and probable origin.

NameCompositionRemarks
Uraninite, Cleveite, Bröggerite, Nivenite, PitchblendeOxides of uranium and lead. Usually contains thorium, other rare earths and helium. Uranium 50-80%. Thorium 0–10%Occurs primary as a constituent of rocks and secondary in veins with metalliferous sulphides
Gummite(Pb, Ca) U3SiO12 . 6H2O? Uranium 50–65%An alteration product of uraninite. Formed by the action of percolating waters
Uranophane, UranotilCaO . 2UO3 . 2SiO2 . 6H2O Uranium 44–56%An alteration product of uraninite through gummite
CarnotiteA vanadate of uranium and potassium. Uranium 42–51%Occurs as a secondary mineral impregnating a porous, sedimentary sandstone. Found in Colorado and Utah
UranosphaeriteBi2O3 . 2UO3 . 3H2O. Uranium 41%Alteration product of other uranium minerals
Torbernite, CuprouraniteCuO . 2UO3 . P2O5 . 8H2O. Uranium 44–51%„ „
Autunite, CalciouraniteCaO . 2UO3 . P2O5 . 8H2O. Uranium 45–51%„ „
UranocirciteBaO . 2UO3 . P2O5 . 8H2O. Uranium 46%„ „
Phosphuranylite3UO3 . P2O5 . 6H2O. Uranium 58–64%„ „
ZuneriteCuO . 2UO3 . As2O5 . 8H2O. Uranium 46%„ „
UranospiniteCaO . 2UO3 . As2O5 . 8H2O. Uranium 49%„ „
Walpurgite5Bi2O3 . 3UO3 . As2O5 . 12H2O. Uranium 16%„ „
ThorogummiteUO3 . 3ThO2 . 3SiO2 . 6H2O? Uranium 41%A variety of gummite
Thorite, Orangite, UranothoriteThSiO4. Uranium 1–10%. Thorium oxide 48–71%A primary constituent of pegmatite dikes
ThorianiteOxide of thorium, uranium, the rare earths and lead. Contains a relatively large proportion of helium. Uranium 9–10%. Thorium oxide 73–77%Occurs as a primary constituent of a pegmatite dike in Ceylon. Geological age probably Archean
SamarskiteNiobate and tantalate of rare earths. Uranium 8–10%Primary constituent of pegmatite dikes
FergusoniteMetaniobate and tantalate of rare earths. Uranium 1–6%„ „
EuxeniteNiobate and titanate of rare earths. Uranium 3–10%„ „
MonazitePhosphate of the rare earths, chiefly cerium. Uranium 0·3–0·4%„ „

INDEX.

The numbers refer to the pages.

CAMBRIDGE: PRINTED BY JOHN CLAY, M.A. AT THE UNIVERSITY PRESS.

CAMBRIDGE PHYSICAL SERIES.

Conduction of Electricity through Gases. By J. J. Thomson, D.Sc., LL.D., Ph.D., F.R.S., Fellow of Trinity College and Cavendish Professor of Experimental Physics. Demy 8vo. viii + 568 pp. 16s.

CONTENTS.