THE QUANTUM 
AND ITS 
INTERPRETATION 
By 
H. STANLEY ALLEN 
M.A., D.Sc. 
DIRECTOR OF PHYSICS RESEARCH LABORATORY 
AND PROFESSOR OF NATURAL PHILOSOPHY IN 
THE UNIVERSITY OF ST. ANDREWS 
T HE quantum theory demands a new 
outlook on the fundamental prob 
lems of physics—the constitution of matter 
and the nature of radiation. In tracing 
the history of the quantum and in seeking 
an interpretation a middle course is steered 
between a mathematical and a descriptive 
treatment. Various suggested explana 
tions are discussed, the magnetic aspect 
of the subject being emphasized. Al 
though the problem is far from being 
completely solved, the new matrix and 
wave mechanics offer a promising mode 
of attack. 
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