POPULAR SCIENTIFIC LECTURES.

BY THE SAME AUTHOR.

The Science of Mechanics. Translated from the Second German Edition by T. J. McCormack. 250 Cuts and Illustrations. 534 Pages. Half Morocco, Gilt Top. Price, $2.50.

Contributions to the Analysis of the Sensations. Translated by C. M. Williams. With Notes and New Additions by the Author. 200 Pages. 36 Cuts. Price, $1.00.

Popular Scientific Lectures. Translated by T. J. McCormack. Third Revised and Enlarged Edition. 411 Pages. 59 Cuts. Cloth, $1.50; Paper, 50 cents.

THE OPEN COURT PUBLISHING CO.,
324 DEARBORN ST., CHICAGO.

POPULAR
SCIENTIFIC LECTURES

BY
ERNST MACH

FORMERLY PROFESSOR OF PHYSICS IN THE UNIVERSITY OF PRAGUE, NOW PROFESSOR OF THE HISTORY AND THEORY OF INDUCTIVE SCIENCE IN THE UNIVERSITY OF VIENNA

TRANSLATED
BY
THOMAS J. McCORMACK

THIRD EDITION, REVISED AND ENLARGED

WITH FIFTY-NINE CUTS AND DIAGRAMS

CHICAGO
THE OPEN COURT PUBLISHING COMPANY

FOR SALE BY
Kegan Paul, Trench, Truebner & Co., LONDON
1898

COPYRIGHT

By The Open Court Publishing Co.

AUTHOR'S PREFACE TO THE FIRST EDITION.

Popular lectures, owing to the knowledge they presuppose, and the time they occupy, can afford only a modicum of instruction. They must select for this purpose easy subjects, and restrict themselves to the exposition of the simplest and the most essential points. Nevertheless, by an appropriate choice of the matter, the charm and the poetry of research can be conveyed by them. It is only necessary to set forth the attractive and the alluring features of a problem, and to show what broad domains of fact can be illuminated by the light radiating from the solution of a single and ofttimes unobtrusive point.

Furthermore, such lectures can exercise a favorable influence by showing the substantial sameness of scientific and every-day thought. The public, in this way, loses its shyness towards scientific questions, and acquires an interest in scientific work which is a great help to the inquirer. The latter, in his turn, is brought to understand that his work is a small part only of the universal process of life, and that the results of his labors must redound to the benefit not only of himself and a few of his associates, but to that of the collective whole.

I sincerely hope that these lectures, in the present excellent translation, will be productive of good in the direction indicated.

E. Mach.

Prague, December, 1894.

[Pg vii]
[Pg vi]

TRANSLATOR'S NOTE TO THE THIRD EDITION.

The present third edition of this work has been enlarged by the addition of a new lecture, "On Some Phenomena Attending the Flight of Projectiles." The additions to the second consisted of the following four lectures and articles: Professor Mach's Vienna Inaugural Lecture, "The Part Played by Accident in Invention and Discovery," the lecture on "Sensations of Orientation," recently delivered and summing up the results of an important psychological investigation, and two historical articles (see Appendix) on Acoustics and Sight.

The lectures extend over a long period, from 1864 to 1898, and differ greatly in style, contents, and purpose. They were first published in collected form in English; afterwards two German editions were called for.

As the dates of the first five lectures are not given in the footnotes they are here appended. The first lecture, "On the Forms of Liquids," was delivered in 1868 and published with that "On Symmetry" in 1872 (Prague). The second and third lectures, on acoustics, were first published in 1865 (Graz); the fourth and fifth, on optics, in 1867 (Graz). They belong to the earliest period of Professor Mach's scientific activity, and with the lectures on electrostatics and education will more than realise the hope expressed in the author's Preface.

The eighth, ninth, tenth, eleventh, and twelfth lectures are of a more philosophical character and deal principally with the methods and nature of scientific inquiry. In the ideas summarised in them will be found one of the most important contributions to the theory of knowledge made in the last quarter of a century. Significant hints in psychological method, and exemplary specimen-researches in psychology and physics, are also presented; while in physics many ideas find their first discussion that afterwards, under other names and other authorship, became rallying-cries in this department of inquiry.

All the proofs of this translation have been read by Professor Mach himself.

T. J. McCormack.

La Salle, Ill., May, 1898.

TABLE OF CONTENTS.

•    page
• The Forms of Liquids   1
• The Fibres of Corti   17
• On the Causes of Harmony   32
• The Velocity of Light   48
• Why Has Man Two Eyes?   66
• On Symmetry   89
• public@vhost@g@gutenberg@html@files@39508@[email protected]#ON_THE_FUNDAMENTAL_CONCEPTS"