# Popular Science Monthly/Volume 60/December 1901/Scientific Literature

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THE AGRICULTURAL YEARBOOK.
The Yearbook of the United States Department of Agriculture has taken rank as one of the important annuals of this country, and in point of circulation is hardly equaled. This is due to the munificence of the Federal Government in appropriating $300,000 annually for its publication, in an edition of half a million copies, and to the care which is given by the Department of Agriculture to the preparation of timely and interesting articles and appropriate illustrations. The Yearbook takes the place of the annual report of the Secretary, which was naturally a more formal document and less likely to attract the average reader's attention. In its present form it presents an attractive appearance, and its many illustrations and long list of short articles on a variety of subjects invite attention. The volume for 1900 comprises nearly nine hundred pages, and is illustrated by eighty-seven plates, nine of them colored, and eighty-eight text figures. In addition to the executive reports, which occupy less than eighty pages, it contains thirty-one articles on various phases of the Department's work or other subjects of direct interest to agriculture. Only a part of these can be mentioned, but enough to indicate the range of subjects and that the volume is not alone of interest and value to the farmers of the country. In an article on Smyrna fig culture in the United States, Dr. Howard describes the successful introduction by the Department of the Blastophaga, the insect which fertilizes the fig and has enabled the production of Smyrna figs of good quality in this country; and one on the date palm tells what has been done for the promotion of that industry by the introduction of the best I varieties into Arizona, where it flourishes even in soils heavily impregnated with alkali. Wheat growing in the semi-arid districts has been rendered less uncertain, it is thought, by the introduction of macaroni and several other varieties of wheat, which have already given promise. Articles on the food of nestling birds and how birds affect the orchard illustrate the practical bearings of a phase of work which is concerned with the food habits of birds under different conditions, to ascertain what kinds are beneficial and what injurious to the farmer and fruit grower; while one on the food value of the potato gives some practical results of the work of the Department in another direction. There are two articles on practical forestry and forest extension, several on injurious insects and their repression, a helpful one on practical irrigation, two on road building, in which subject the Department is taking an active interest, and two on meteorology. One of the latter, on hot waves, the conditions which produce them and their effects on agriculture, is of special interest even though it does not suggest any relief. The free rural delivery of mails, although in no way connected with the Department of Agriculture, comes so close to its farmer constituents that an account of the working of that system does not seem out of place in its Yearbook. The four thousand routes now in operation provide for the daily delivery of mail at the scattered homes of about three and a half million of rural population. The work done in a long life devoted to agriculture, horticulture and kindred subjects by the late William Saunders, who had been connected with the Department since its establishment in 1862, is the subject of a short sketch, ​and his portrait occupies the place of honor as the frontispiece to the volume. An appendix of over 200 pages contains a vast amount of condensed information on a variety of subjects, and bears out the inference that no effort has been spared to make this, like the preceding volumes, worthy of the large expenditure involved and the wide distribution it is given.
METEOROLOGY.
A well-arranged, readable and generally satisfactory presentation of the principles of meteorology may be found in the latest text-book on that subject, Börnstein's Leitfaden der Wetterkunde. The general plan of the book is conventional, but there are one or two features which deserve special mention. In the introduction an interesting figure shows the 'thermo-isopleths' for Berlin, these lines indicating, in one drawing, both the diurnal and the annual march of the air temperature. In the chapter on temperature all important matters are considered, including the recent work of Pettersson and Meinardus on long-range forecasts for Europe based on the special characteristics of the Gulf Stream, and a brief summary of the meteorological results of the international balloon ascents, in some of which the author took part. The physiological effects of atmospheric humidity receive some consideration, and a new table is given showing, for a number of stations, the probable fall of temperature below the wet-bulb reading of an afternoon hour, to be expected during the night. This table is useful in predicting frost. The much-agitated question of hail prevention by cannon firing is briefly taken up in the sections on rainfall. The chapter on weather is very complete. Thunderstorm charts and theories; the weather types of van Bebber and Köppen, and the weather services of the world, are all discussed, the weather types being fully illustrated. A noteworthy feature of the work is the nine colored views of cloud types, similar to those in the International Cloud Atlas. This is the first text-book to have such elaborate illustrations of clouds. A fairly good working bibliography is appended, which includes comparatively few works in English. The index is good, but the chapters are not numbered, and there are no section headings in the text.
PSYCHOLOGY.
'An Introduction to Psychology,' by Mary Whiton Calkins (The Macmillan Company), is one of the text-books in psychology that makes it obvious that psychology is to a great extent all things to all men. The books do not present the same body of accepted truth, varying only in such matters as arrangement and adaptation to students of different capacities and different practical needs. Changing your psychology book is not so much changing your coat as changing your skin. Miss Calkins, for instance, includes the study of 'the conscious relation of the human self to a divine self as a sample of certain mysterious relationships between selves apart from those due to physical agencies. She includes a sympathetic discussion of the phenomena of telepathy and veridical hallucinations. Many of her co-workers would rigorously exclude both these topics. She makes no mention of the instructive reactions which are the fons et origo of our later intellects and wills or of the law of habit which would seem to many to be the key to comprehension of mental processes. Yet Miss Calkins's book is as scholarly and fair an exposition of the elements of psychology as any of the recent books. Those who seek from psychology training in analysis and discrimination and approach the study from an interest in general philosophy will find it a particularly helpful manual.