THE EVOLUTION OF PHYSICS The now numerous public which tries with some success to keep abreast of the movement in science, from seeing its mental habits every day upset, and from occasionally witnessing unexpected discoveries that produce a more lively sensation from their reaction on social life, is led to suppose that we live in a really exceptional epoch, scored by profound crises and illustrated by extraordinary discoveries, whose... more...

PART I THE SPECIAL THEORY OF RELATIVITY PHYSICAL MEANING OF GEOMETRICAL PROPOSITIONS In your schooldays most of you who read this book made acquaintance with the noble building of Euclid's geometry, and you remember — perhaps with more respect than love — the magnificent structure, on the lofty staircase of which you were chased about for uncounted hours by conscientious teachers. By reason of our past experience, you would... more...

PREFACE A collection of about 2000 questions asked by children forms the foundation on which this book is built. Rather than decide what it is that children ought to know, or what knowledge could best be fitted into some educational theory, an attempt was made to find out what children want to know. The obvious way to discover this was to let them ask questions. The questions collected were asked by several hundred children in the upper... more...

Biographical Sketch of Nikola Tesla.   While a large portion of the European family has been surging westward during the last three or four hundred years, settling the vast continents of America, another, but smaller, portion has been doing frontier work in the Old World, protecting the rear by beating back the "unspeakable Turk" and reclaiming gradually the fair lands that endure the curse of Mohammedan rule. For a long time the Slav... more...

THE DIAGRAMS. The diagrams, it will be observed, are grouped under the seasons, and they indicate the positions of the constellations as they appear at 9 o'clock p.m. in mid-season. To facilitate finding and observing the constellations, the student should face in the direction indicated in the text. This applies to all constellations excepting those near the zenith. The four large plates are so arranged that the observer is supposed to be... more...

TWO NEW INSTITUTIONS OF SCIENCE; ANDTHE SCENES WHICH ATTENDED THEIR CHRISTENING. In the month of August last, two events took place in the city of Albany, which have more than an ephemeral interest. They occurred in close connection with the proceedings of a Scientific Convention, and the memory of them deserves to be cherished as a recollection of the easy way in which Science may be popularized and be rendered so generally acceptable that the... more...

CHAPTER I. THE DISCOVERY OF THE UNIVERSE The beginning of the victorious career of modern science was very largely due to the making of two stimulating discoveries at the close of the Middle Ages. One was the discovery of the earth: the other the discovery of the universe. Men were confined, like molluscs in their shells, by a belief that they occupied the centre of a comparatively small disk—some ventured to say a globe—which was... more...

All knowledge is essentially one. The object-matter upon which intellect exerts itself, does not affect the subjective act of knowing. Physics, when stripped of that which is merely contingent, becomes metaphysics. Physical science deals with object-matter, and discusses the signs by which nature communicates her message—that is, phenomena. Metaphysical science has to do with the subject-mind, and discusses the meaning of the message. The... more...

THE FUTURE OF ASTRONOMY BY PROFESSOR EDWARD C. PICKERING HARVARD COLLEGE OBSERVATORY It is claimed by astronomers that their science is not only the oldest, but that it is the most highly developed of the sciences. Indeed it should be so, since no other science has ever received such support from royalty, from the state and from the private individual. However this may be, there is no doubt that in recent years astronomers have had granted to... more...

The most obvious and the most distinctive features of the History of Civilisation, during the last fifty years, is the wonderful increase of industrial production by the application of machinery, the improvement of old technical processes and the invention of new ones, accompanied by an even more remarkable development of old and new means of locomotion and intercommunication. By this rapid and vast multiplication of the commodities and... more...