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 In offering this book to teachers of elementary chemistry the authors lay no claim to any great originality. It has been their aim to prepare a text-book constructed along lines which have become recognized as best suited to an elementary treatment of the subject. At the same time they have made a consistent effort to make the text clear in outline, simple in style and language, conservatively modern in point of view, and thoroughly... more...

WHAT IS DARWINISM? This is a question which needs an answer. Great confusion and diversity of opinion prevail as to the real views of the man whose writings have agitated the whole world, scientific and religious. If a man says he is a Darwinian, many understand him to avow himself virtually an atheist; while another understands him as saying that he adopts some harmless form of the doctrine of evolution. This is a great evil. It is obviously... more...

I. PREHISTORIC SCIENCE To speak of a prehistoric science may seem like a contradiction of terms. The word prehistoric seems to imply barbarism, while science, clearly enough, seems the outgrowth of civilization; but rightly considered, there is no contradiction. For, on the one hand, man had ceased to be a barbarian long before the beginning of what we call the historical period; and, on the other hand, science, of a kind, is no less a precursor... more...

CHAPTER I ON RAYS PROPAGATED IN STRAIGHT LINES   s happens in all the sciences in which Geometry is applied to matter, the demonstrations concerning Optics are founded on truths drawn from experience. Such are that the rays of light are propagated in straight lines; that the angles of reflexion and of incidence are equal; and that in refraction the ray is bent according to the law of sines, now so well known, and which is no less certain... more...

THE SCIENTIFIC EVIDENCES OF ORGANIC EVOLUTION. Although it is generally recognised that the Origin of Species has produced an effect both on the science and the philosophy of our age which is without a parallel in the history of thought, admirers of Mr. Darwin's genius are frequently surprised at the ignorance of his work which is displayed by many persons who can scarcely be said to belong to the uncultured classes. The reason of this ignorance... more...

In seeking to discover Darwin's relation to his predecessors it is useful to distinguish the various services which he rendered to the theory of organic evolution. (I) As everyone knows, the general idea of the Doctrine of Descent is that the plants and animals of the present day are the lineal descendants of ancestors on the whole somewhat simpler, that these again are descended from yet simpler forms, and so on backwards towards the literal... more...

THE DEVELOPMENT HYPOTHESIS. [Originally published in The Leader, for March 20, 1852. Brief though it is, I place this essay before the rest, partly because with the exception of a similarly-brief essay on "Use and Beauty", it came first in order of time, but chiefly because it came first in order of thought, and struck the keynote of all that was to follow.] In a debate upon the development hypothesis, lately narrated to me by a friend, one... more...

CHAPTER I A REVALUATION OF THE EVIDENCE ON WHICH THE THEORY OF EVOLUTION WAS BASED We use the word evolution in many ways—to include many different kinds of changes. There is hardly any other scientific term that is used so carelessly—to imply so much, to mean so little. Three Kinds of Evolution We speak of the evolution of the stars, of the evolution of the horse, of the evolution of the steam engine, as though they were all... more...

PREFACE. This work was originally written to be delivered as a lecture; but as its pages continued to multiply, it was suggested to the author by numerous friends that it ought to be published in book-form; this, at last, the author concluded to do. This work, therefore, does not claim to be an exhaustive discussion of the various departments of which it treats; but rather it has been the aim of the author to present the more interesting... more...