In the following section Dr. Draper shows how, by means of Lord Kelvin's "harmonic analysis," which separates the tide-generating forces of each kind into a number of ideal components, results of practical value are obtained. In Chapter XIII a very ingenious instrument for tide prediction which has been in use for some time by the Indian Government is described. The recording part of the machine is simply a paper-wound drum, on which a pencil point makes a graphic record. When the tides of a given port are desired, it is only necessary to set the instrument according to the tidal components, obtained by harmonic analysis and the time chosen for the beginning of the tide table, and then start it at the proper moment. It takes about four hours to run off the tidal curve for a year. This curve is then measured, and the year's tide table readily made out. Dr. Darwin informs us that a very similar instrument is now in course of construction for the United States Government. The remainder of the work consists of a more detailed discussion of the various disturbing influences which interfere with the simplicity of tidal movements—displacement of the earth's axis, earthquakes, etc, a long discussion of tidal friction, a study of the laws of rotating liquid masses, the nebular hypothesis, and finally a chapter on Saturn's rings. The text in many places will be found difficult to understand by the general reader, despite the author's efforts to fully and simply explain every point, and it seems questionable whether a thorough discussion of tidal phenomena can be made simple enough for the layman's comprehension. The volume can not be read by any one, however, without instruction, and is much the best general discussion of tidal phenomena which we have seen.
GENERAL NOTICES.
The Elementary Zoölogy of Frank E. Beddard[45] contains an account of a few types selected from the chief groups of the animal kingdom, followed and accompanied by a consideration of some of the more general conclusions of biology. A type system has to be used, but the author has endeavored to obviate the great fault of that method—the liability of the students conceiving that the characters of the species selected for description are distinctive of a wider assemblage of forms—by emphasizing here and there the differences between allied groups. The question arises whether to begin with the higher forms and go down to the lower, which some authorities believe to be the course easier of comprehension by the student, or to follow the inverse method. The author prefers to begin with the lower forms and gradually work to the higher as the course having the undoubted advantage of presenting the facts in a logical sequence. He accordingly begins with the amœba and proceeds upward. The treatment is simple and lucid. Novelty has not been sought in the illustrations, though there are several new ones, but selections have been made from the best already drawn.
An Introductory Logic[46] grew out of the lectures of the author, Prof. J. E. Creighton, to undergraduate classes in Cornell University; is intended primarily as a text-book for students, and aims at being both practical and theoretical. The broad view is taken in the definition of the subject that logic is the science of thought, or the science that investigates the process of thinking; and the author expresses himself convinced that, in spite of some difficulties, formal logic is one of the most valuable instruments in modern education for promoting clear thinking and for developing critical habits of mind. To doubters of the advisability of attempting to include a theory of thought or a philosophy of mind in an elementary course in logic, Professor Creighton replies that psychology having differentiated itself from philosophy and become a "natural" science, no longer undertakes to describe all that the mind is and does. "It belongs to logic to investigate intelligence as a knowing function, just as it is the task of ethics to deal with the practical or active mental faculties." Logic must first be a science before it can become an art, but it can not be regarded as an art in the sense that it furnishes a definite set of rules for thinking correctly. What it can do is to show the method by which new truths have been discovered and the general conditions that must always be fulfilled in reasoning correctly. The treatment in the text follows the usual order, except that the author, keeping clear of artificial diction, writes in talking English that is easy to be comprehended.
There are no more vital problems in the evolution of society than those connected with the point of view, the outlook, of the great masses of the "working people." These people form the backbone, the potential energy of society; an acquaintance with their views of ethics and life, and manner of living, is of the utmost importance, not only per se, but especially because of the efficient direction which such a knowledge can give the attempts at improving these latter, and through them society at large. Mr. Walter Wyckoff has, apparently actuated by some such view as this, in combination perhaps with a desire for a novel experience, made a two years' trip across the continent, living chiefly among the lowest and most improvident class of manual laborers; making his own living by their methods, and, by means of the close contact, studying them from a vantage point of unusual value. The account of this expedition[47] is, as it could not fail to be, no matter who the traveler might have been, of great interest and value. But in Mr. Wyckoff's hands the story has an added attraction through the literary ability of the author. There is much material of practical scientific value in the volume; it should prove especially suggestive and useful to some of our charity organization workers who apparently find it so difficult to govern their work by reason rather than emotion. There are one or two rather unpleasant lapses, the most marked of which advertises in a Chicago police station Mr. Wyckoff's great linguistic attainments, but the work is generally free from this sort of weakness, and is on the whole very well worth reading for instruction as well as entertainment.
The Manual of Determinative Mineralogy of Professors George J. Brush and Samuel L. Penfield[48] is intended primarily to be used in the identification of minerals, and that purpose has been kept prominently in view. The present edition is a complete revision of Professor Brush's original work, the value of which and the estimation in which it is held by its constituency are attested by the fact that fourteen editions of it have been issued since it first appeared in 1874. A revision of the parts devoted to blowpipe analysis and the chemical reactions of the elements was published in 1896. To the present edition a chapter is added on the physical properties of minerals, devoted chiefly to crystallography, in which the endeavor has been made to present the subject as simply as possible. Importance has been attached to the description of those forms which are of most frequent occurrence, and the examples chosen to illustrate the different systems represent, as a rule, the simple forms that prevail in specimens of common minerals, while rare and complex forms are treated very briefly. The introduction of a large number of species since 1874 has made a complete rearrangement necessary in the analytical tables; and they have been so developed that tests for characteristic chemical constituents furnish the chief means of identification. Stress is laid upon the importance of determining the chemical constituents as a factor in securing accuracy in identification.
Demonstrator G. S. Newth opens his Manual of Chemical Analysis[49] with a protest against the thought of "doing" analysis without learning more than the minimum amount of chemistry, and against teaching and practicing it in such a manner as to degrade it to the level "of a purely mechanical and often unintelligible series of rule-of-thumb operations." He says he has done his best to make it "as little of a cram book as possible," and has endeavored "to teach analytical chemistry as well as analysis"—that is, the theoretical as well as the practical side of the subject. He begins with emphasizing the importance of the student making himself practically familiar with certain simple operations he will have to perform constantly, and gives clear, concise definitions of such terms as filtration, solution, evaporation, fusion, precipitation, ignition, etc., which relate to those operations. He condemns slovenly formulas and mechanical notes, but commends real notes of the student's own observations. In his treatment he excludes merely descriptive details that have no bearing on analysis; and in quantitative analysis, prefers describing fully a few typical methods and processes to covering much ground slightly.
The Ingersoll Lectureship at Harvard University is constituted on a legacy by Miss Caroline H. Ingersoll, carrying out the wishes of her father, George G. Ingersoll, for the foundation of an annual lectureship on the "Immortality of Man," to which no conditions as to doctrine or method of treatment are attached. The purpose of the lectures, or perhaps their operation, as defined by Prof. William James, is that out of the series may emerge a collective literature worthy of the theme. Professor James took as the special subject of his lecture[50] the answer to two objections to the doctrine of immortality: first, the absolute dependence of our spiritual life, as we know it here, on the brain; and the second relating to "the incredible and intolerable number of beings which, with our modern imagination, we must believe to be immortal, if immortality be true." To the former objection the author replies that thought is not a productive but a permissive or transmissive function of the brain; when the brain decays, the sphere of being that supplied the consciousness is still intact, and the stream still goes on; to the second, that spiritual being is not as material being, that each new mind brings "its own edition of the universe of space" along with it, that there is no crowding or interference, and that the supply of individual life in the universe can never possibly exceed the demand.
The first number of In Lantern Land, a monthly journal "devoted to literature, the fine arts, the play, with some discussion of passing events," Charles Dexter Allen and William Newnham Carleton, editors, gives promise of a literary journal of elevated tone. It holds its aim to be unprejudiced and independent. (Published at Hartford, Conn., by Charles Dexter Allen, for one dollar a year.)
Mr. Henry Carr Pearson presents in his Greek Prose Composition (American Book Company, 90 cents) results of his own experience in the class room. The aim of the book is to combine study of the essentials of Greek syntax with practice in translating connected English into Attic Greek, and to afford convenient practice in writing Greek at sight. The work is in three parts: Part I, containing, in graded lessons, the principal points of Greek syntax, designed for use at the beginning of the second year's study of Greek; Part II, short simple English sentences modeled after sentences in Xenophon's Anabasis, for daily use in connection with reading of the text; and Part III, connected English prose, graded, also based on the Anabasis. Review lessons are introduced, and a Greek-English vocabulary is provided.