Walther
Bothe
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The
Coincidence Method
Before
embarking on the subject of my lecture, permit me to devote a few words
to the man to whom, apart from my teacher, Max
Planck, I owe so much, and who died ten years ago after a long
period of painful suffering. In 1912 Hans Geiger was appointed Director
of a new Laboratory for Radioactivity at the Physikalisch-Technische
Reichsanstalt, Berlin-Charlottenburg of which Emil Warburg was then the
President; previous to this, he had worked for six years under
Rutherford at Manchester. In June 1913, I became Geiger’s assistant.
The Laboratory for Radioactivity consisted of only two rooms at the
time; at a later date, when tests of radioactive substances became more
extensive, it expanded into four rooms. This modesty of his room
requirements – Geiger repeatedly stated that he had no desire for a
giant institute – is characteristic of the principal trait in Geiger’s
personality as a scientist: the desire to keep scientific work within
economic bounds. No doubt, the unique influence of Rutherford had
something to do with this; equally indubitably, this influence
harmonized with a natural tendency. However this may be, the
experiments by Geiger and Marsden on the scattering of alpha rays are
known to form part of the beginning of the entire experimental atom
physics of recent days. I think the main lesson which I have learnt
from Geiger is to select from a large number of possible and perhaps
useful experiments that which appears the most urgent at the moment,
and to do this experiment with the simplest possible apparatus, i.e.
clearly arranged and variable apparatus.
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