The New Physics and Its Evolution

The New Physics and Its
Evolution

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Lucien Poincare
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Title: The New Physics and Its Evolution
Author: Lucien Poincare
Release Date: February 28, 2005 [eBook #15207]
Language: En
Character set encoding: ISO-8859-1
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The International Scientific Series
THE NEW PHYSICS AND ITS EVOLUTION
by
LUCIEN POINCARÉ Inspéctéur-General de l'Instruction Publique
Being the Authorized Translation of _LA PHYSIQUE MODERNE,
SON ÉVOLUTION_
New York D. Appleton and Company
1909

Prefatory Note
M. Lucien Poincaré is one of the distinguished family of

mathematicians which has during the last few years given a Minister of
Finance to the Republic and a President to the Académie des Sciences.
He is also one of the nineteen Inspectors-General of Public Instruction
who are charged with the duty of visiting the different universities and
_lycées_ in France and of reporting upon the state of the studies there
pursued. Hence he is in an excellent position to appreciate at its proper
value the extraordinary change which has lately revolutionized physical
science, while his official position has kept him aloof from the
controversies aroused by the discovery of radium and by recent
speculations on the constitution of matter.
M. Poincaré's object and method in writing the book are sufficiently
explained in the preface which follows; but it may be remarked that the
best of methods has its defects, and the excessive condensation which
has alone made it possible to include the last decade's discoveries in
physical science within a compass of some 300 pages has, perhaps,
made the facts here noted assimilable with difficulty by the untrained
reader. To remedy this as far as possible, I have prefixed to the present
translation a table of contents so extended as to form a fairly complete
digest of the book, while full indexes of authors and subjects have also
been added. The few notes necessary either for better elucidation of the
terms employed, or for giving account of discoveries made while these
pages were passing through the press, may be distinguished from the
author's own by the signature "ED."
THE EDITOR.
ROYAL INSTITUTION OF GREAT BRITAIN, April 1907.

Author's Preface
During the last ten years so many works have accumulated in the
domain of Physics, and so many new theories have been propounded,
that those who follow with interest the progress of science, and even
some professed scholars, absorbed as they are in their own special
studies, find themselves at sea in a confusion more apparent than real.
It has therefore occurred to me that it might be useful to write a book
which, while avoiding too great insistence on purely technical details,
should try to make known the general results at which physicists have
lately arrived, and to indicate the direction and import which should be
ascribed to those speculations on the constitution of matter, and the

discussions on the nature of first principles, to which it has become, so
to speak, the fashion of the present day to devote oneself.
I have endeavoured throughout to rely only on the experiments in
which we can place the most confidence, and, above all, to show how
the ideas prevailing at the present day have been formed, by tracing
their evolution, and rapidly examining the successive transformations
which have brought them to their present condition.
In order to understand the text, the reader will have no need to consult
any treatise on physics, for I have throughout given the necessary
definitions and set forth the fundamental facts. Moreover, while strictly
employing exact expressions, I have avoided the use of mathematical
language. Algebra is an admirable tongue, but there are many occasions
where it can only be used with much discretion.
Nothing would be easier than to point out many great omissions from
this little volume; but some, at all events, are not involuntary.
Certain questions which are still too confused have been put on one
side, as have a few others which form an important collection for a
special study to be possibly made later. Thus, as regards electrical
phenomena, the relations between electricity and optics, as also the
theories of ionization, the electronic hypothesis, etc., have been treated
at some length; but it has not been thought necessary to dilate upon the
modes of production and utilization of the current, upon the phenomena
of magnetism, or upon