Popular Science Monthly/Volume 50/January 1897/Scientific Literature
The query that Prof. Trowbridge takes as the title of his recent book is one of the most difficult to give a direct answer to that have been propounded to modern science. The answer given in this volume presents electricity to the adult reader from a much different point of view than was afforded by the treatise of his school or college days—say, ten to thirty years ago. Our author has designed his book to give a popular presentation of Maxwell's theory of the electro-magnetic origin of light and heat, for he holds that by studying the transformations of energy involved in this theory we can obtain the best idea of what electricity is. The plan of the volume is to treat in successive chapters the leading phases of the subject as illustrated by important processes or pieces of apparatus. In the short chapter on measurements in electricity he shows that gravitation is used to measure all our electrical manifestations, and then passes to a discussion of the nature of gravitation itself. In dealing with magnetism he quotes the expressions of Franklin and his contemporary, Prof. Winthrop, on this subject, and some of Count Rumford's views on the transformation of energy—a subject that bears a fundamental relation to the modern science of electricity. Passing to later times, he shows that it is to considerations of the nature of the surrounding medium that we owe the chief advances in our knowledge of magnetism. His account of the dynamo machine begins with a comparison of Faraday's galvanometer with one of the present day. This is followed by a description of the construction of a simple piece of apparatus by means of which the essential features of the dynamo can be explained. Subjects of other chapters are: Alternating Currents, Transmission of Power by Electricity, The Leyden Jar, Step-up Transformers, The Electro-magnetic Theory of Light and the Ether, The X Rays, and The Sun. The book is popular but not elementary. The treatment is everywhere philosophical, though by this we are far from meaning metaphysical. Technological applications appear only by way of illustration. The volume contains some fifty diagrams and a frontispiece plate.
For an elementary and thoroughly popular account of electrical phenomena the reader should go to the Library of Useful Stories. We feel safe in saying that every electrical contrivance known to the general public is described and explained in the little book by Mr. Munro. The chapters on applications of electricity are preceded by accounts of the apparatus and processes employed in the several modes of generating the electric force. Throughout the volume is enough of history and anecdote to justify the title of "Story," and enough of fundamental principles to base an intelligent acquaintance with the phenomena of this branch of science upon. Where the history of discoveries and inventions is being told, the reader should remember that the author is English, and has a full share of the amusing insular notion that everything worth mentioning was done first by an Englishman. In the matter of terminology the book has been edited so as to make it conform to American usage; some changes have been made in the cuts also, and new matter has been added to the same end. There are a hundred illustrations and an adequate index.
It is a little startling to see a renowned chemist described in the title of a biography as "Poet and Philosopher." Davy, however, was certainly occupied with "natural philosophy," and the designation of poet is far from misapplied. The pleasing character of the Century Science Series is admirably maintained by the attractive life-history of him that Dr. Thorpe has prepared. Of the talents that characterized Davy's adult life the first to be manifested in his boyhood was his poetic faculty. His best school exercises, we are told, were his translations into English verse, and he was often called upon by his schoolmates to write valentines and similar effusions for them. Later it was undoubtedly the vivid imagery and sympathetic mode of expression derived from this faculty which made his popular lectures the salvation of the Royal Institution before that establishment had his brilliant discoveries to lean upon. Our author evidently has assumed that his readers wish to know about Davy's scientific career, and this thread runs unbroken throughout the volume. At the same time the human side of the man is shown in references to his fondness for angling, his devotion to his mother, his friendship with Coleridge, Maria Edgeworth, and other persons of intellect, the incidents of his marriage, and the characteristics of his disposition. Davy's last important discovery, the principle of the miner's safety lamp, as well as his first, the anæsthetic property of laughing gas, have a practical value that easily commands popular appreciation, while his isolation of the metals of the alkalies, his demonstration of the elementary character of chlorine, and his researches on iodine give him a permanently high rank among chemists. Dr. Thorpe has relied largely upon the memoirs of Dr. Paris and of Dr. John Davy, brother of Sir Humphry, carefully weighing one against the other where they disagree, and he has had much other material in the form of letters, journals, and memoirs of contemporaries, records of societies, pamphlets of the time, etc.
At the age when the child comes under the care of the teacher some of his mental faculties are already well advanced on the path of development. One must go back of this age in order to get a full understanding of the way in which his mind unfolds. Prof. Compayré goes back to the moment of birth, and even quotes inferences of several observers as to the psychology of prenatal existence. There is a good deal of physiology in the chapter on the newborn child and in that on movements, the first forms of activity. From the pains that the author takes with fundamental considerations one would almost think he was a German instead of a Frenchman. He sums up the history of the child's motions as "irresistible, blind, fatal impulses at the start; then, little by little, conscious desires, thoughtless, but lit up by an intellectual representation, by the idea of an end to be attained; finally, will and efforts." The statement of the child's muscular needs given in this book ought to convince any reader of the cruelty of enforcing the command to "sit still" upon young children. Prof. Compayré next considers the development of sight, showing that the child is half blind at birth, and only gradually gains the full use of his eyes. The author (or translator) is rather too literal in interpreting photophobia as "fear" of light, and the same inaccuracy is observable in other writers on this subject. The newborn child has no real fear of light; the proper term is intolerance of light. The other senses are also rudimentary at birth, that of touch being best developed. In discussing the emotions our author affirms that the pleasures early exceed the pains in the child's experience. The natural modes of expressing the feelings can be readily observed in children, who do not restrain such manifestations. Prof. Compayré finds the first evidences of memory in the nursling's recognition of familiar faces. The acquirement of language, which itself depends upon a certain development of the memory, he regards as greatly quickening the further growth of this faculty. The imagination, consciousness, attention, and association of ideas are described in the two remaining chapters of this volume. The concluding part of the work will deal with reasoning, learning to talk, the development of the moral sense, and related topics.