I cannot conclude this preface without thanking those who have assisted me in the preparation of this book—Sir William Osler, who read the first draft of the manuscript, and aided me with his counsel; Dr. Charles Singer, who read all the chapters in manuscript, and to whom I am indebted for advice in reference to the illustrations and for many other valuable suggestions; the officers of the Bodleian Library, whose courtesy was unfailing during the year I worked there; Professor Henry Crew, who helped in the revision of two of the chapters by his judicious criticism; Professor J. E. Rush, whose knowledge of bacteriology improved the chapter on Pasteur; Professor L. O. Grondahl, who read one of the chapters relating to the history of physics and suggested important emendations; and Dr. John A. Brashear, who contributed valuable information in reference to the activities of Samuel Pierpont Langley. I wish to express my gratitude also to Miss Florence Bonnet for aid in the correction of the manuscript.

W. Libby.

February 2, 1917.

[CONTENTS]

I. [Science and Practical Needs—Egypt and Babylonia] 1
II. [The Influence of Abstract Thought—Greece: Aristotle] 15
III. [Scientific Theory Subordinated to Application—Rome: Vitruvius] 30
IV. [The Continuity of Science—The Medieval Church and the Arabs] 43
V. [The Classification of the Sciences—Francis Bacon] 57
VI. [Scientific Method—Gilbert, Galileo, Harvey, Descartes] 72
VII. [Science as Measurement—Tycho Brahe, Kepler, Boyle] 86
VIII. [Coöperation in Science—The Royal Society] 99
IX. [Science and the Struggle for Liberty—Benjamin Franklin] 114
X. [The Interaction of the Sciences—Werner, Hutton, Black, Hall, William Smith] 129
XI. [Science and Religion—Kant, Lambert, Laplace, Sir William Herschel] 142
XII. [The Reign of Law—Dalton, Joule] 155
XIII. [The Scientist—Sir Humphry Davy] 170
XIV. [Scientific Prediction—The Discovery of Neptune] 184
XV. [Science and Travel—The Voyage of the Beagle] 197
XVI. [Science and War—Pasteur, Lister] 213
XVII. [Science and Invention—Langley's Aeroplane] 231
XVIII. [Scientific Hypothesis—Radioactive Substances] 245
XIX. [The Scientific Imagination] 258
XX. [Science and Democratic Culture] 270
[Index] 283

[ILLUSTRATIONS]