Front matter
Reading edition
Harper’s Library of Living Thought
Fig. 1.—Haloes in cleavage flake of Biotite. ×70.
Fig. 2.—Radium Halo (lower part of field) and Thorium Halo (upper part of field) in Biotite cut across cleavage. ×100.
Fig. 3.—Haloes in cleavage flake of Biotite. ×85.
Fig. 4.—Haloes due to Ra. emanation (inner disc), Ra. A and Ra. B. ×450.
PLEOCHROIC HALOES
THE AGE OF THE EARTH
BY ARTHUR HOLMES B.Sc., A.R.C.S.
MEMBER OF THE IMPERIAL COLLEGE FELLOW OF THE GEOLOGICAL SOCIETY OF LONDON FELLOW OF THE ROYAL GEOGRAPHICAL SOCIETY
ILLUSTRATED WITH TWENTY FIGURES AND DIAGRAMS
LONDON AND NEW YORK HARPER & BROTHERS 45 ALBEMARLE STREET, W. 1913
Published March, 1913
TO PROFESSOR THE HON. R. J. STRUTT AND PROFESSOR W. W. WATTS IN GRATITUDE FOR EARLY TRAINING AND ADVICE