Page:Popular Science Monthly Volume 12.djvu/769

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ism and its operation, points out the delicate complexity of its effects in a way that will interest all curious-minded readers. Mr. Edison, by this invention, has done for sound what Daguerre did for light—made it possible to fix and permanently retain the most fleeting impressions. We pointed out, last month, the marvelous capacities of cold iron, magnetism, and an electric wire; but the capacities of the phonograph are still more marvelous, for, with only a vibrating plate, a sheet of tin-foil, and a crank, it is possible to arrest and fix all kinds of sound, and, having preserved them as long as metals will hold their properties, to give them forth again in all their original qualities. The voice, indeed, is somewhat muffled and minified when returned from the iron tongue of the phonograph; but its intonations, inflections, pauses, and quality, are rendered with surprising fidelity. By the simple turning of the crank, the machine talks, sings, shouts, laughs, whistles, and coughs, so naturally and distinctly, that the listener can hardly believe his senses, or escape from the suspicion that there is some ventriloquist hocus-pocus about it, or a little fellow concealed somewhere about the arrangement. But the fact is established, and must be made the most of. A machine, as simple as a coffee-mill, hears a speech or a song, and gives it back as perfectly as it was at first uttered by the living organs of voice. And so, again, we have the lesson repeated, with still greater emphasis, that we must raise our estimate of the powers and potencies of "mere dead matter."



Physiography: An Introduction to the Study of Nature. By T. H. Huxley, F.R.S. With Illustrations and Colored Plates. Second edition. Pp. 377. New York: D. Appleton & Co. Price, $2.50.

This volume has been prepared as a school text-book on the subject hitherto known as physical geography, but in its method it is very different from the usual works upon that subject. Of course, Prof. Huxley could not enter upon this field without taking his own view of its method of treatment, and making an original book, but beyond this he has unquestionably made a very valuable contribution to educational literature. In the following passage from the preface he puts the subject upon its rational and proper basis. He says:

"I do not think that a description of the earth which commences by telling a child that it is an oblate spheroid moving round the sun in an elliptical orbit, and ends without giving him the slightest hint toward understanding the ordnance-map of his own county, or any suggestion as to the meaning of the phenomena offered by the brook which runs through his village, or the gravel-pit whence the roads are mended, is calculated either to interest or to instruct. And the attempt to convey scientific conceptions without the appeal to observation which can alone give such conceptions firmness and reality, appears to me to be in direct antagonism to the fundamental principles of scientific education."

Prof. Huxley was led to the preparation of this volume in consequence of having been invited, several years ago, to give a course of lectures before the London Institution, which were intended to initiate young people into the elements of physical science. Prof. Huxley took the opportunity thus afforded to put into practical shape ideas long entertained respecting the proper method of approaching the study of Nature. Twelve lectures were given, not on any particular branch of knowledge, but on natural phenomena in general, and the title "Physiography" was taken to distinguish both as to matter and method between the subject and what is commonly understood as physical geography. The ideas which Prof. Huxley aimed to embody in these lectures, and which characterize the present work, are thus happily presented by himself:

"It appeared to me to be plainly dictated by common-sense, that the teacher, who wishes to lead his pupil to form a clear mental picture of the order which pervades the multiform and endlessly-shifting phenomena of Nature, should commence with the familiar facts of the scholar's daily experience; and that, from the firm ground of such experience he should lead the beginner, step by step, to remoter objects and to the less readily comprehensible relations of things. In short, that the knowledge of the child should, of set purpose, be made to grow, in the same man-