VIII. THE LATENT IMAGE - - - - - - - - - - - - - - 202

IX. PLEOCHROIC HALOES - - - - - - - - - - - - - - 214

X. THE USE OF RADIUM IN MEDICINE - - - - - - - - - 244

XI. SKATING - - - - - - - - - - - - - - - - - - - 260

XII. A SPECULATION AS TO A PRE-MATERIAL UNIVERSE - 288

LIST OF ILLUSTRATIONS

PLATE I. LAKE OF LUCERNE, LOOKING WEST FROM BRUNNEN -
Frontispiece

PLATE II. "UPLIFTED FROM THE SEAS." CLIFFS OF THE TITLIS,
SWITZERLAND - to face p. 4

PLATE III. AN ALPINE TORRENT AT WORK--VAL D'HERENS, SWITZERLAND -
to face p. 31

PLATE IV. EARTH PILLARS--VAL D'HERENS - to face p. 34

PLATE V. "SCENES OF DESOLATION." THE WEISSHORN SEEN FROM BELLA
TOLA, SWITZERLAND - to face p. 40

PLATE VI. ALLUVIAL CONE--NICOLAI THAL, SWITZERLAND. MORAINE ON
ALETSCH GLACIER SWITZERLAND - to face p. 50