A Popular History of Science

to place before him or her such an account of the principal steps in the progress of science as will be intelligible throughout. The whole body and matter of any department of knowledge cannot of course be all passed in review; but those researches, discoveries, and theories which have contributed to furnish its form and principles may be traced in their inception, progression, and completion. In the following chapters the endeavour has been to follow the main lines along which each science has developed, by adducing such specific experiments, observations, and reasonings as support or illustrate the most important results. The intermixture with the scientific matter of more or less brief biographical notes concerning the great men who have made science, and the introduction of the portraits of many of them, will, it is hoped, import into the present work some of that element of "human interest in which books of pure science are often accused of being deficient.

As science is a word with a wide extent of application, it will of course be readily understood that it is used in the title of this work with a limitation of its sense, and this limitation will best be defined by an enumeration of the branches of science treated of in the present volume. These are: Astronomy; the Physical Sciences-light, heat, electricity, etc.; Chemistry, and the group which we venture to call the Natural History Sciences-botany, zoology, geology, etc.; and, to a certain small extent, Mathematics. As the last is a study popularly supposed to offer few attractions, we hasten to add, that it is only because they have proved mighty instruments in advancing the other sciences, that we have given some brief and very simple illustrations of the nature of such inventions as logarithms, the Cartesian geometry, and the infinitesimal calculus; but, as it is not to be expected that the general reader will most commonly be a votary of

"The hard-grain'd Muses of the cube and square,"

no reference is made to the subsequent development of mathe

matics, and the recondite methods of modern analysis. It may here be proper to observe that as a science advances to perfection it is more and more concerned with processes of mathematical deductions. There are some sciences which have long consisted chiefly of deductions made from a few simple principles established by experience once for all. Such are mechanics, hydrostatics, parts of optics and of astronomy. The abstract mathematical forms of such parts of science make them less generally attractive, and where in the following pages these sciences are entered upon under the designation of "The Mathematical Sciences," it is usually some of the experimental or inductive particulars that are discussed.

The plan upon which the subject matter has been arranged is to give the first three chapters to ancient science, divided mainly into ancient Greek, Alexandrian Greek, Arabian, and Medieval schools. A chapter is then apportioned to the science of the sixteenth century generally, while for each succeeding century separate chapters are assigned to the several sciences or groups of sciences. Three chapters, specially devoted to the respective labours of the epoch-forming men, Galileo, Bacon, and Newton, take their places among the rest and carry on the narration. The division of the matter according to centuries has of course no intrinsic significance, being adopted merely for convenience of reference; and the classification of the sciences into mathematical sciences, natural history sciences, etc., suggested by the titles given to some of the chapters, is to a great extent also arbitrary. Two more remarks we have to make for the reader's avoidance of misconceptions. He must not assume that the subjects which he finds touched upon in the following pages under the name of each philosopher necessarily represent the whole of that philosopher's useful scientific activity. Still less will he be entitled to suppose that the names of the few living men of science which happen to find a place in this volume are introduced by reason of the preeminence of their owners above the rest of the many distinguished cultivators of science, whose splendid labours also are

advancing the boundaries of knowledge in every direction; it is only the limitations imposed by the scope and aim of our pages that hinder us from concluding with the display of a long roll of the honoured names and the inestimable works that add lustre to an age already rich

"With the fairy tales of science, and the long result of Time."

CONTENTS.

CHAPTER I.

ANCIENT SCIENCE.

Page I

INTRODUCTORY, 1-Thales, 5-Anaximander, 10-Anaximanes, 11-Pytha-

goras, 12-Leucippus, 17-Democritus, 18—Protagoras, 20—Socrates, 20—Plato,

20-Aristotle, 25-Hippocrates of Cos, 30-Theophrastus, 32.

CHAPTER II.

ALEXANDRIAN SCIENCE.

Page 33

ALEXANDRIA, 33-Euclid, 35-Hippocrates of Chios, 36-Aristarchus of Samos,