Radio-Activity

CAMBRIDGE PHYSICAL SERIES.

General Editors:—F. H. Neville, M.A., F.R.S.

and W. C. D. Whetham, M.A., F.R.S.

RADIO-ACTIVITY

CAMBRIDGE UNIVERSITY PRESS WAREHOUSE

C. F. CLAY, Manager.

London: FETTER LANE, E.C.

Glasgow: 50, WELLINGTON STREET.

ALSO

London: H. K. LEWIS, 136, GOWER STREET, W.C.

Leipzig: F. A. BROCKHAUS.

New York: THE MACMILLAN COMPANY.

Bombay and Calcutta: MACMILLAN AND CO., Ltd.

RADIO-ACTIVITY

E. RUTHERFORD, D.Sc., F.R.S., F.R.S.C.

MACDONALD PROFESSOR OF PHYSICS, McGILL UNIVERSITY, MONTREAL

SECOND EDITION

CAMBRIDGE

AT THE UNIVERSITY PRESS

1905

First Edition 1904

Second Edition 1905

J. J. THOMSON

A TRIBUTE OF MY RESPECT AND ADMIRATION