Du Bois-Reymond, and still more Virchow, ignore these proofs, because they are to a great extent ignorant alike of the inquiries and results, of the methods and the aims of our modern morphology, and this ignorance may be accounted for partly by the one-sided direction which their biological studies have taken, partly by the fact that there are few universities where the study of morphology is so behindhand as at the University of Berlin. Fully twenty years have now elapsed since the great Johannes Mueller died, the last naturalist who could command all the departments of biology. The three great provinces of science which had been reunited into a triune kingdom under his powerful sceptre, were then divided among three professors' chairs: Du Bois-Reymond took that of physiology, Virchow, theoretical pathology (pathological anatomy and physiology), and the third, and most important chair, that of morphology (human and comparative anatomy, including the history of evolution) fell to Boguslaus Reichert. This choice was, as is now universally admitted, an incomprehensible mistake. Instead of calling Carl Gegenbaur, or Max Schultze, or some one else of youthful capacity and vigour to the chair of morphology—a science which is the first foundation of zoology as well as of medicine—in Reichert they selected an elderly school anatomist cramped by strong old-fashioned notions, who had done some good and useful specialist work, but whose general views had developed all awry, and who for the unexampled obscurity of his conceptions and the confusion of his ideas, was outdone by none save only Adolf Bastian. For twenty years this man has represented animal morphology in the second university of Germany, and in these twenty years hardly any work worth mentioning has been done there in the whole of this vast department—neither by the master nor by his pupils. We have only to compare the many worthless anatomical productions of Berlin during these two decades (for instance, the recent confused work by Fritsch on the brain of fishes) with the rich mine of invaluable work produced during the preceding twenty years by Johannes Mueller and his crowd of disciples.

But, as if this were not enough, Reichert took advantage of his influential position to hinder as far as possible all scientific study of morphology. For example, he, with the co-operation of his colleagues, carried through that pretended "reform" of medical examination which puts the so-called Tentamen physicum in the place of the philosophicum; philosophy was entirely eliminated. Zoology and botany, which for centuries have been very justly regarded as the indispensable foundation of all instruction in natural science for the young medical student, disappeared from the curriculum. Only, as if in scorn of these sciences, in each examination a small place was reserved for comparative anatomy—for that most difficult and philosophical part of animal morphology which cannot be at all understood without some previous knowledge of the other branches of zoology. And yet comparative anatomy and the history of development are the indispensable preliminary steps to a true scientific comprehension of human anatomy, that most essential foundation of all medical knowledge. Without the vivifying idea of development, mere anatomical knowledge is an empty and lifeless cramming of the memory.

In the place of morphology, thus degraded from its office, a detailed study of physiology was introduced, but always in a one-sided direction. Now these two great branches of biology, which are equally important and have an equal claim on our attention, are so dependent the one on the other, that a real scientific understanding of organic life can never be obtained without due relative study of both. The masterly and incomparable teaching of Johannes Mueller owed a great part of its captivating charm to his equitable regard for morphology and physiology, as well as to his comprehensive treatment, from the broadest point of view, of the enormous mass of details to be dealt with. I therefore have not the smallest doubt that the morphological training of medical students, as at present conducted at Berlin under the influence of Reichert and his colleagues, is as far behind that of Mueller's day, twenty or thirty years ago, in all general comprehension of the typical organism, as it is in advance of it in specialist acquirements.

In medical, as in all other scientific learning, the highest aim does not consist in seeking to accumulate a vast chaotic mass of isolated items of knowledge, but in a general comprehension of the science, its aims and problems. The teacher should, above everything, guide the pupil to this general knowledge, and then it will be easy to him, by the aid of proper methods, to acquire mastery in each individual and special branch. Thus in medicine, as in every other science, he is not the best qualified who, on Bastian's method, has loaded his memory with a confused mass of undigested facts, and has flung them all together into his brain without any order; but, on the contrary, he who has practically digested a considerable number of the most important facts, and has critically co-ordinated them to a harmonious whole. It is precisely under this aspect that transmutation is of such inestimable value to morphology; it enables us to rise from the bare empirical knowledge of numberless isolated facts to a philosophical conception of their efficient causes.

The aversion and contempt which the theories of descent and selection have met with at Berlin, more than in any other place, is in great measure to be explained by the circumstance that, during the last two decades, morphological studies have been more neglected in that university than any others. In no other city of Germany has evolution in general, as well as Darwinism in particular, been so little valued, so utterly misunderstood, and treated with such sovereign disdain as in Berlin. Nay, Adolf Bastian, the most zealous of all the Berlin opponents of our doctrines, has insisted on these facts with peculiar satisfaction. Of all the conspicuous naturalists of Berlin only one accepted the doctrine of transmutation from the beginning with sincere warmth and full conviction, being, indeed, persuaded of its truth even before Darwin himself. This was the gifted botanist Alexander Braun, who is lately dead—a morphologist who was equally distinguished by the extent of his comprehensive knowledge of details, as by his philosophical mastery over them. His firm conviction of the truth of the theory of descent is all the more remarkable because he was at the same time a spotless character, a pious Christian in the best sense of the word, and an extremely conservative politician; a striking example that these convictions can dwell side by side with the principles of the recent doctrines of evolution in one and the same person. But in comparison with the powerful influence of the rest of the Berlin naturalists who, for the most part, are decided opponents of transmutation, and who have only lately—a few of them, to follow the fashion—become converts to it, a man like Alexander Braun could have no effect in procuring that it should be taught.

However, this is not the first time that this very Berlin society of learned men has set itself with remarkable firmness against the most important advances of science. Virchow's former colleague, the deceased Stahl, with a similar purpose and with great success, preached this principle: "Science must turn back again." Just as at the present day the Berlin biologists have opposed the most obstinate and pertinacious resistance to the greatest scientific stride of this century, so did it happen in former times with regard to other doctrines of progress. We have only to recall Caspar Friedrich Wolff, the great inquirer, who in 1759 first detected the nature of the individual processes of development in the animal ovum, and founded on it his observations in his "Theoria Generationes," which marked an epoch in biological science. The Berlin savants, full of the prevailing prejudices, so contrived at that time that Wolff never once could obtain the permission which he craved, to lecture publicly, and in consequence found himself compelled to retire to St. Petersburg for the sake of peace. And yet in that instance there was no question of a "theory" properly so-called. For the fundamental theory of generation—the "theory of epigenesis"—as propounded by Wolff was nothing more than a simple, general exposition of embryological facts which he had been the first to recognise, and of whose truth every one might convince himself by direct observation. In spite of this, for another half century, the predominant error of the "Preformation-theory" continued to be universally accepted—the ludicrous and nonsensical doctrine, supported by the authority of Haller, that all the successive generations of animals exist preconceived and enclosed one within the other, and that no individual development ever takes place! Nulla est epigenesis! (Compare my "Evolution of Man," vol. i. p. 31.)

But it would appear that it is the fate of that most interesting of all sciences, the history of evolution, to find its most important steps and its greatest discoveries met by the firmest and most persistent opposition. For while Wolff's fundamental theory of epigenesis, which was promulgated in 1759, was not recognised until 1812, Lamarck's theory of descent, founded in 1809, had to wait fully fifty years before Darwin, in 1859, showed it to be the greatest acquisition of modern science; and during that period, in spite of all the progress made in empirical science, how persistently this most comprehensive of all biological theories was combated. We need only recollect how, in 1830, the celebrated George Cuvier silenced its most eloquent supporter, Geoffroy St. Hilaire, in the midst of the Paris Academy, and how almost at the same time its founder, the great Lamarck, ended his life in blindness, misery and want, while his opponent Cuvier was enjoying the highest honours and the greatest splendour. And yet we know now that the despised and contemned Lamarck and Geoffroy had already grasped truths of the highest significance, while Cuvier's much-admired and universally-accepted theory of creation is now on all hands neglected as an absurd and untenable delusion. But as neither Haller as against Wolff, nor Cuvier as against Lamarck, could permanently hinder the progress of free inquiry, neither will Virchow succeed in turning back the course of Darwin's admirable achievement; no, not even when he is supported by the discourses of his friend Bastian.

While we cannot but earnestly lament Virchow's inimical attitude in this great struggle for truth, we must not overlook the effects of his well-founded authority in a yet wider sphere. For instance, the hostile attitude which the greater part of the Berlin press persistently maintains towards the doctrine of development (particularly the Liberal "National-Zeitung") is to be referred to the influence of his authority. But much as this reactionary vein, in this and in other intelligent circles at Berlin, must be regretted on the one hand, on the other we must observe that by this evil we have been preserved from a far greater one. This greater evil—the greatest, in fact, which German science could have to encounter—would be the monopoly of knowledge at Berlin; a Centralisation of Science. The injurious fruits of this system of centralisation in France, for instance, the continual deterioration of French science through the Parisian "Monopoly of Knowledge," and its steady decline during half a century from the sublimest heights—these are all well known. From such a centralisation of German science—which would be especially dangerous if it occurred in the capital, Berlin—we may hope to be preserved; in the first place by the manifold differences and the many-sided individuality of the German national spirit, the much-abused German provincialism (Particularismus). While these provincial modes of thought can never have any permanent political value, nor be productive of a desirable form of government, it is beyond a doubt that their outcome has been fruitful and happy for German science. For it owes its splendid pre-eminence over that of other countries precisely to the many centres of culture which were offered by those numerous petty capitals of the minor German States which strove to outdo each other in eager emulation. It is to be hoped that this happy decentralisation of science in our politically united fatherland may continue to subsist!

And next to this centrifugal tendency of our German national mind nothing will so greatly contribute to it as a vigorous opposition to the free advance of science, such as is just now declaring itself in the metropolis. For by just so much as Berlin is dragged back by it in the mighty onward stream of free intellectual movement, by so much will it see itself outstripped by the other seats of culture in Germany, which follow the stream with enthusiasm, or at least without resistance. If Emil du Bois-Reymond raises the cry of "Ignorabimus," and Rudolf Virchow his still more audacious one of "Restringamur," as the watchwords of science, then, from Jena, let the shout be raised and echoed from a hundred other universities—"Impavidi progrediamur!"

THE END.

* * * * *

WORKS OF PROFESSOR ERNST HAECKEL.

FREEDOM IN SCIENCE AND TEACHING. From the German of ERNST HAECKEL. With a Prefatory Note by T. H. Huxley, F.R.S. 1 vol., 12mo.

THE EVOLUTION OF MAN. A Popular Exposition of the Principal Points of Human Ontogeny and Phylogeny. From the German of ERNST HAECKEL, Professor in the University of Jena, author of "The History of Creation," etc. With numerous Illustrations. In two vols., 12mo. Cloth. Price, $5.00.

From the London Saturday Review.

"In this excellent translation of Professor Haeckel's work, the English reader has access to the latest doctrines of the Continental school of evolution, in its application to the history of man. It is in Germany, beyond any other European country, that the impulse given by Darwin twenty years ago to the theory of evolution has influenced the whole tenor of philosophical opinion. There may be, and are, differences in the degree to which the doctrine may be held capable of extension into the domain of mind and morals; but there is no denying, in scientific circles at least, that as regards the physical history of organic nature much has been done toward making good a continuous scheme of being."

THE HISTORY OF CREATION; or, the Development of the Earth and its Inhabitants by the Action of Natural Causes. A Popular Exposition of the Doctrine of Evolution in general, and of that of Darwin, Goethe, and Lamarck in particular. From the German of ERNST HAECKEL, Professor in the University of Jena. The translation revised by Professor E. Ray Lankester, M.A., F.R.S., Fellow of Exeter College, Oxford. Illustrated with Lithographic Plates. In 2 vols., 12mo. Cloth, $5.00.

* * * * *

WORKS OF THOMAS H. HUXLEY, LL. D., F.R.S.

MAN'S PLACE IN NATURE. 1 vol., 12mo. Cloth, $1.25.

ON THE ORIGIN OF SPECIES. 1 vol., 12mo. Cloth, $1.00.

MORE CRITICISMS ON DARWIN, AND ADMINISTRATIVE NIHILISM. 1 vol., 12mo. Limp cloth, 50 cents.

A MANUAL OF THE ANATOMY OF VERTEBRATED ANIMALS. Illustrated. 1 vol., 12mo. Cloth, $2.50.

A MANUAL OF THE ANATOMY OF INVERTEBRATED ANIMALS. $2.50.

LAY SERMONS, ADDRESSES, AND REVIEWS. 1 vol., 12mo. Cloth, $1.75.

CRITIQUES AND ADDRESSES. 12mo. Cloth, $1.50.

AMERICAN ADDRESSES; with a Lecture on the Study of Biology. 12mo. Cloth, $1.25.

PHYSIOGRAPHY: an Introduction to the Study of Nature. With Illustrations and Colored Plates. 12mo. Cloth, $2.50.

ELEMENTS OF PHYSIOLOGY AND HYGIENE. By T. H. HUXLEY and W. J. YOUMANS. 1 vol., 12mo. $1.50.

* * * * *

RECENT EDUCATIONAL WORKS.

Principles and Practice of Teaching.

By JAMES JOHONNOT.

1 volume, 12mo. Cloth. 396 pages. Price, $1.50.

CONTENTS.

I. WHAT IS EDUCATION?

II. THE MENTAL POWERS: their Order of Development, and the Methods most conducive to Normal Growth.

III. OBJECTIVE TEACHING: its Methods, Aims, and Principles.

IV. SUBJECTIVE TEACHING: its Aims and Place in the Course of Instruction.

V. OBJECT-LESSONS: their Value and Limitations.

VI. RELATIVE VALUE OF THE DIFFERENT STUDIES in a Course of Instruction.

VII. PESTALOZZI, and his Contributions to Educational Science.

VIII. FROEBEL AND THE KINDERGARTEN.

IX. AGASSIZ; and SCIENCE IN ITS RELATION TO TEACHING.

X. CONTRASTED SYSTEMS OF EDUCATION.

XI. PHYSICAL CULTURE.

XII. AESTHETIC CULTURE.

XIII. MORAL CULTURE.

XIV. A COURSE OF STUDY.

XV. COUNTRY SCHOOLS.

Extract from Preface.

"Experience is beginning to show that teaching, like every other department of human thought and activity, must change with the changing conditions of society, or it will fall in the rear of civilization, and become an obstacle to improvement.... In this volume an endeavor has been made to examine education from the standpoint of modern thought, and to contribute something to the solution of the problems that are forcing themselves upon the attention of educators. To these ends, a concise statement of the well-settled principles of psychology has been made, and a connected view of the interdependence of the sciences given, to serve as a guide to methods of instruction, and to determine the subject-matter best adapted to each stage of development. The systems of several of the great educational reformers have been analyzed, with a view to ascertain precisely what each has contributed to the science of teaching, and how far their ideas conform to psychological laws; and an endeavor has been made to combine the principles derived from both experience and philosophy into one coherent system."

ELEMENTARY LESSONS IN HISTORICAL ENGLISH GRAMMAR, containing Accidence and Word-Formation. By the Rev. RICHARD MORRIS, LL. D., President of the Philological Society, London. 18mo. Cloth, 254 pages. Price, $1.00.

WORDS, and how to put them together. By HARLAN H. BALLARD, Principal of Lenox High-School, Lenox, Mass. 18mo. Cloth. Price, 40 cents.

GENERAL HISTORY, from B. C. 800 to A. D. 1876. Outlined in Diagrams and Tables; with Index and Genealogies. For General Reference, and for Schools and Colleges. By SAMUEL WILLARD, A. M., M. D., Professor of History in Chicago High-School. 8vo. Cloth. Price, $2.00.

HARKNESS'S PREPARATORY COURSE IN LATIN PROSE AUTHORS, comprising four books of Caesar's Gallic War, Sallust's Catiline, and eight Orations of Cicero. With Notes, Illustrations, a Map of Gaul, and a Special Dictionary. 12mo. Cloth. Price, $1.75.

HARKNESS'S SALLUST'S CATILINE, with Notes and a Special Vocabulary. 12mo. Cloth. Price, $1.15.

THE LATIN SPEAKER. Easy Dialogues, and other Selections for Memorizing and Declaiming in the Latin Language. By FRANK SEWALL, A. M. 12mo. Cloth. Price, $1.00.

* * * * *

New Volume of "The International Scientific Series."

EDUCATION AS A SCIENCE.

BY

ALEXANDER BAIN, LL. D.,

PROFESSOR OF LOGIC IN THE UNIVERSITY OF ABERDEEN.

1 vol., 12mo. Cloth, price, $1.75.

"In the present work I have surveyed the Teaching Art, as far as possible, from a scientific point of view; which means, among other things, that the maxims of ordinary experience are tested and amended by bringing them under the best ascertained laws of the mind."—From Preface.

"Dr. Bain's renovated curriculum is certainly extensive enough, even if it omits Greek and Latin. According to this, higher education should embrace—first, science; second, the humanities, including history and the social science, and some portions of the universal literature; and, third, English composition and literature."—New York Evening Express.

"The work should become a text-book for teachers, not to be followed servilely or thoughtlessly, but used for its suggestiveness."—Boston Gazette.

"Professor Bain is not a novice in this field. His work is admirable in many respects for teacher, parent, and pupil."—Philadelphia North American.

"A work of great value to all teachers who study it intelligently."—Boston Advertiser._

"At once speculative and practical, entering largely into the philosophy of teaching, and manfully handling facts."—Philadelphia Press.

* * * * *

PRIMERS

IN SCIENCE, HISTORY and LITERATURE.

18mo. Flexible cloth, 45 cents each.

I.—Edited by Professors HUXLEY, ROSCOE, and BALFOUR STEWART.

SCIENCE PRIMERS.

Chemistry H. E. ROSCOE. Physics BALFOUR STEWART. Physical Geography A. GEIKIE. Geology A. GEIKIE. Physiology M. FOSTER. Astronomy J. N. LOCKYER. Botany J. D. HOOKER. Logic W. S. JEVONS. Inventional Geometry W. G. SPENCER. Pianoforte FRANKLIN TAYLOR. Political Economy W. S. JEVONS.

II.—Edited by J. R. GREEN, M.A., Examiner in the School of Modern History at Oxford.

HISTORY PRIMERS.

Greece C. A. FYFFE. Rome M. CREIGHTON. Europe E. A. FREEMAN. Old Greek Life J. P. MAHAFFY. Roman Antiquities A. S. WILKINS. Geography GEORGE GROVE.

III.—Edited by J. R. GREEN, M.A.

LITERATURE PRIMERS.

English Grammar R. MORRIS. English Literature STOPFORD BROOKE. Philology J. PEILE. Classical Geography M. F. TOZER Shakespeare E. DOWDEN. Studies in Bryant J. ALDEN. Greek Literature R. C. JEBB. English Grammar Exercises R. MORRIS. Homer W. E. GLADSTONE.

(Others in preparation.)

The object of these primers is to convey information in such a manner as to make it both intelligible and interesting to very young pupils, and so to discipline their minds as to incline them to more systematic after-studies. They are not only an aid to the pupil, but to the teacher, lightening the task of each by an agreeable, easy, and natural method of instruction. In the Science Series some simple experiments have been devised, leading up to the chief truths of each science. By this means the pupil's interest is excited, and the memory is impressed so as to retain without difficulty the facts brought under observation. The woodcuts which illustrate these primers serve the same purpose, embellishing and explaining the text at the same time.

* * * * *

APPLETONS' SCHOOL READERS,

CONSISTING OF FIVE BOOKS.

BY

W. T. HARRIS, LL. D., Superintendent of Schools, St. Louis, Mo.

A. J. RICKOFF, A. M., Superintendent of Instruction, Cleveland, O.

MARK BAILEY, A. M., Instructor in Elocution, Yale College.

RETAIL PRICES.

APPLETONS' FIRST READER $0.25 APPLETONS' SECOND READER .40 APPLETONS' THIRD READER .52 APPLETONS' FOURTH READER .70 APPLETONS' FIFTH READER 1.25

CHIEF MERITS.

These Readers, while avoiding extremes and one-sided tendencies, combine into one harmonious whole the several results desirable to be attained in a series of school reading-books. These include good pictorial illustrations, a combination of the word and phonic methods, careful grading, drill on the peculiar combinations of letters that represent vowel-sounds, correct spelling, exercises well arranged for the pupil's preparation by himself (so that he shall learn the great lessons of self-help, self-dependence, the habit of application), exercises that develop a practical command of correct forms of expression, good literary taste, close critical power of thought, and ability to interpret the entire meaning of the language of others.

THE AUTHORS.

The high rank which the authors have attained in the educational field and their long and successful experience in practical school-work especially fit them for the preparation of text-books that will embody all the best elements of modern educative ideas. In the schools of St. Louis and Cleveland, over which two of them have long presided, the subject of reading has received more than usual attention, and with results that have established for them a wide reputation for superior elocutionary discipline and accomplishments. Feeling the need of a series of reading-books harmonizing in all respects with the modes of instruction growing out of their long tentative work, they have carefully prepared these volumes in the belief that the special features enumerated will commend them to practical teachers everywhere.

Of Professor Bailey, Instructor of Elocution in Yale College, it is needless to speak, for he is known throughout the Union as being without a peer in his profession. His methods make natural, not mechanical readers.

* * * * *

A SHORT HISTORY

OF

Natural Science and the Progress of Discovery,

FROM THE TIME OF THE GREEKS TO THE PRESENT DAY.

FOR SCHOOLS AND YOUNG PERSONS.

By ARABELLA B. BUCKLEY.

With Illustrations. 12mo. Cloth, $2.00.

"During many years the author acted as secretary to Sir Charles Lyell, and was brought in contact with many of the leading scientific men of the day, and felt very forcibly how many important facts and generalizations of science, which are of great value both in the formation of character and in giving a true estimate of life and its conditions, are totally unknown to the majority of otherwise well-educated persons. This work has been written for this purpose, and it is not too much to say that it will effect its purpose."—European Mail.

"The volume is attractive as a book of anecdotes of men of science and their discoveries. Its remarkable features are the sound judgment with which the true landmarks of scientific history are selected, the conciseness of the information conveyed, and the interest with which the whole subject is nevertheless invested. Its style is strictly adapted to its avowed purpose of furnishing a text-book for the use of schools and young persons."—London Daily News.

"Before we had read half-a-dozen pages of this book we laid it down with an expression of admiration of the wonderful powers of the writer. And our opinion has increased in intensity as we have gone on, till we have come to the conclusion that it is a book worthy of being ranked with Whewell's 'History of the Inductive Sciences'; it is one which should be first placed in the hands of every one who proposes to become a student of natural science, and it would be well if it were adopted as a standard volume in all our schools."—Popular Science Review.

"A most admirable little volume. It is a classified resume of the chief discoveries in physical science. To the young student it is a book to open up new worlds with every chapter."—Graphic.

"We have nothing but praise for this interesting book. Miss Buckley has the rare faculty of being able to write for young people."—London Spectator.

"The book will be a valuable aid in the study of the elements of natural science."—Journal of Education.

* * * * *

FAIRY-LAND OF SCIENCE.

BY ARABELLA B. BUCKLEY,

Author of "A Short History of Natural Science," etc.

WITH NUMEROUS ILLUSTRATIONS.

12mo Cloth, price, $1.50.

"A child's reading-book admirably adapted to the purpose intended. The young reader is referred to nature itself rather than to books, and is taught to observe and investigate, and not to rest satisfied with a collection of dull definitions learned by rote and worthless to the possessor. The present work will be found a valuable and interesting addition to the somewhat overcrowded child's library."—Boston Gazette.

"Written in a style so simple and lucid as to be within the comprehension of an intelligent child, and yet it will be found entertaining to maturer minds."—Baltimore Gazette.

"It deserves to take a permanent place in the literature of youth."—London Times.

"The ease of her style, the charm of her illustrations, and the clearness with which she explains what is abstruse, are no doubt the result of much labor; but there is nothing labored in her pages, and the reader must be dull indeed who takes up this volume without finding much to attract attention and to stimulate inquiry."—Pall Mall Gazette.

"So interesting that having once opened it we do not know how to leave off reading."—Saturday Review.

"We are compelled to admit that there is indeed a fairy-land of science. This is the fairy-land upon which Miss Arabella Buckley lectured last year, and upon which she has now produced a child's reading-book, which is most charmingly illustrated, and which is in every way rendered especially interesting to the juvenile reader."—London Athenaeum.

* * * * *

THE EXPERIMENTAL SCIENCE SERIES.

In neat 12mo volumes, bound in cloth, fully illustrated. Price per volume, $1.00.

This series of scientific books for boys, girls, and students of every age, was designed by Prof. Alfred M. Mayer, Ph. D., at the Stevens Institute of Technology, Hoboken, New Jersey. Every book is addressed directly to the young student, and he is taught to construct his own apparatus out of the cheapest and most common materials to be found. Should the reader make all the apparatus described in the first book of this series, he will spend only $12.40.

NOW READY:

I.—LIGHT.

A Series of Simple, Entertaining, and Inexpensive Experiments in the Phenomena of Light, for Students of every Age.

By ALFRED M. MAYER and CHARLES BARNARD.

II.—SOUND:

A Series of Simple, Entertaining, and Inexpensive Experiments in the Phenomena of Sound, for the Use of Students of every Age.

By ALFRED MARSHALL MAYER,

Professor of Physics in the Stevens Institute of Technology; Member of the National Academy of Sciences; of the American Philosophical Society, Philadelphia; of the American Academy of Arts and Sciences, Boston; of the New York Academy of Sciences; of the German Astronomical Society; of the American Otological Society; and Honorary Member of the New York Ophthalmological Society.

IN ACTIVE PREPARATION:

III. Vision and the Nature of Light.

IV. Electricity and Magnetism.

V. Heat.

VI. Mechanics.

VII. Chemistry.

VIII. The Art of experimenting with Cheap and Simple Instruments.

* * * * *

LIGHT:

A Series of Simple, Entertaining, and Inexpensive Experiments in the Phenomena of Light, for the Use of Students of Every Age.

BY ALFRED M. MAYER and CHARLES BARNARD.

NEAT 12MO VOLUME, FULLY ILLUSTRATED. CLOTH, PRICE, $1.00.

"Professor Mayer has invented a series of experiments in Light which are described by Mr. Barnard. Nothing is more necessary for sound-teaching than experiments made by the pupil, and this book, by considering the difficulty of costly apparatus, has rendered an important service to teacher and student alike. It deals with the sources of light, reflection, refraction, and decomposition of light. The experiments are extremely simple and well suited to young people."—Westminster Review.

"This work describes, in simple language, a number of experiments illustrating the principal properties of light, by means of a beam of sunlight admitted into a dark room, and various contrivances. The experiments are highly ingenious, and the young student can not fail to learn a great deal from the book. As an example of the effective experimental method employed, we may specially mention the device for illustrating the refraction of light. This book is specially designed 'to give to every teacher and scholar the knowledge of the art of experimenting.'"—The Quarterly Journal of Science (London).

"A singularly excellent little hand-book for the use of teachers, parents, and children. The book is admirable both in design and execution. The experiments for which it provides are so simple that an intelligent boy or girl can easily make them, and so beautiful and interesting that even the youngest children must enjoy the exhibition. The experiments here described are abundantly worth all that they cost in money and time in any family where there are boys and girls to be entertained."—New York Evening Post.

"The experiments are capitally selected, and equally as well described. The book is conspicuously free from the multiplicity of confusing directions with which works of the kind too often abound. There is an abundance of excellent illustrations."—New York Scientific American.

"The experiments are for the most part new, and have the merit of combining precision in the methods with extreme simplicity and elegance of design. The value of the book is further enhanced by the numerous carefully-drawn cuts, which add greatly to its beauty."—American Journal of Science and Arts.

* * * * *

SOUND:

A Series of Simple, Entertaining, and Inexpensive Experiments in the Phenomena of Sound, for the Use of Students of Every Age.

By ALFRED MARSHALL MAYER,

Professor of Physics in the Stevens Institute of Technology; Member of the National Academy of Sciences, etc.

Uniform with "LIGHT," first volume of the Series.

Neat 12mo volume, fully illustrated. Cloth, price, $1.00.

"It would be difficult to find a better example of a series which is excellent throughout. This little work is accurate in detail, popular in style, and lucid in arrangement. Every statement is accompanied with ample illustrations. We can heartily recommend it, either as an introduction to the subject or as a satisfactory manual for those who have no time for perusing a larger work. It contains an excellent description, with diagrams, of Faber's Talking Machine and of Edison's Talking Phonograph, which can not fail to be interesting to any reader who takes an interest in the marvelous progress of natural science."—British Quarterly.

"The style of the book is very clear, and the experiments interesting. It can not fail to have an important educational influence."—Westminster Review.

"It would really be difficult to exaggerate the merit, in the sense of consummate adaptation to its modest end, of this little treatise on 'Sound.' It teaches the youthful student how to make experiments for himself, without the help of a trained operator, and at very little expense. These hand-books of Professor Mayer should be in the hands of every teacher of the young."—New York Sun.

"An admirably clear and interesting collection of experiments, described with just the right amount of abstract information and no more, and placed in progressive order. The recent inventions of the phonograph and microphone lend an extraordinary interest to this whole field of experiment, which makes Professor Mayer's manual especially opportune."—Boston Courier.

* * * * *

The Works of Professor E. L. YOUMANS, M. D.

Class-book of Chemistry.

New edition. 12mo. Cloth, $1.50.

The Hand-book of Household Science.

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APPLETONS' CYCLOPAEDIA OF APPLIED MECHANICS.

A DICTIONARY OF

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ILLUSTRATED BY 5,000 ENGRAVINGS.

Edited by PARK BENJAMIN, Ph. D.

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T. A. EDISON, PH. D. RICHARD H. BULL, C. E. SAMUEL WEBBER, C. E. PROF. DE VOLSON WOOD. CHARLES E. EMERY, C. E. JOSHUA ROSE, M. E. PIERRE DE P. RICKETTS, PH. D. HON. ORESTES CLEVELAND. W. T. J. KRAJEWSKI, C. E. S. W. GREEN, ESQ. JOHN BIRKINBINE, C. E. HENRY L. BREVOORT, C. E. LIEUT. A. A. BOYD, U. S. N. ABRAM L. HOLLEY, C. E. COLEMAN SELLERS, M. E. PROF. C. W. McCORD. IRVING M. SCOTT, ESQ. F. A. MCDOWELL, C. E. H. A. MOTT, JR., PH. D. W. H. PAYNE, C. E. GEORGE H. BENJAMIN, M. D. THERON SKELL, C. E. WILLIAM KENT, C. E. W. E. KELLY, ESQ. F. T. THURSTON, C. E. JOHN HOLLINGSWORTH, ESQ.

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