Chapter II: Appendix: A 177

APPENDIX B 184
INDEX 191

LIST OF ILLUSTRATIONS

_Figures printed as plates_
FIG. 1}
FIG. 2} Pleochroic Haloes _Frontispiece_
FIG. 3}
FIG. 4}

FACING PAGE
FIG. 5} Spiral Nebulæ 28
FIG. 6}

FIG. 7} Polar Caps of Mars 39
FIG. 8}

FIG. 12} Photographs of Pitchblende 92
FIG. 13}

_Figures printed in text_
PAGE
FIG. 9. Glacial Movement in S. Scandinavia 40
FIG. 10. Upper Cretaceous Strata of Colorado 45
FIG. 11. Section illustrating the Formation
of Sediments on Continental Shelf 83
FIG. 14. Apparatus for Estimating Radium 106
FIG. 15. Pleochroic Haloes of the Uranium Family 108
FIG. 16. Temperature Gradients 127
FIG. 17. Geological Time Scales 172

APPENDIX A—
Graph I 180
Graph II 181

Table of Radioactive Elements 190

THE AGE OF THE EARTH