Industrial Plants_ Their Arrangement and Construction. By Charles ,Price Day, New York: Engineering Magazine, 1911. 8vo.; 294 pp. Price, $3. Careful study of the Jay-out and construction of industrial buildings is the prim wry step toward efficiency and economy in manufacture. “Industrial Plants” is the oUtCOllH of 11. Day's wide experience as consulting engineer in the construction of some of the most successful shops and faetories in the country. His analyses follow a scientific method which takes into account not only the mere material factors of the problem, but which also looks ahead to the complexities introduced hy the human element-the employees upon whom environment exerts so powerful an influence toward good or bad work, mental or physical. In this phase of the problem the field of the new “scientific management” is invaded. The discussion progresses from the broad general principles of lay-out and arrangement to a consideration of detail as required in specific instances. Charts, diagrams, and inserts point the lessons set forth. j'lrther chapters bear upon the relationship between client and engineer. In “charctcristic modern examples” s(veral la rge factories of varying types are pictured and described, and window-construction and painting arc shown in their relations to adequate lighting. A large insert of a hat factory has red and blue routing lines showing the sequence of operations in the manufacture of hats. Metal-worldng shops are given considerable space, and the considerations bearing on machine-drive are featured in diagrams. The work will wen repay a careful r(ading. The Mutation Theory. By Hugo de Vries. Vol. II. Chicago: The Open Court Publishing Company. 600 pp.; numerous illustrations, 6 colored plates. Price, $4. I was our privilege to review, Shortly after its publication, the first volume of this work, which is destined to take its place beside Darwin's “Origin of Species.” That first volume was devoted to an elaborate discussion of experiments made by Prof. de Vries with Lamarck's evening primrose, and froIn the cxperiments made the conelusion was deduced that species may arise suddenly rather than by that age-long process for which Darwin argued. In the second volume, De VI'ies shows where the accepted Darwinian theory is wrong and where it will be necessary to substitute his own mutation ideas. Darwin himself foresaw the mutation theory, for he distinguished between the multiplication of his “pangenes” Hnd their modification, and saw that without variation “natural selection could do nothing.” With Darwin, variability of any kind suIplies the field in which selection works and sinks to quite a subordinate position in compwrison. De Vries, on the other hand, holds that specific characters do not arise by selection. An old-fashioned biologist may not be inclined to accept the mutation theory (and the more modern biologists arc certainly in favor of it) he has at least shown the necessity of experimental study of species. BVilding for Profit. By Reginald Pel-ham Bolton. New York: The De Vinne Press, 1911. 124 pp.; 15 illustrations. In this book the reader will find an effort to present scientifically the conditions which surround the planning, construction, and operation of a wide variety of metropolitan buildings during the last fifteen years. IIere will be found the main features affecting and deciding values of improved real estate fronl the metropolitan standpoint, so that the investor may know what fundamental principles go to make or mar au investment, what conditions and methods will assist him in deciding upon the preliminary proportions of a structure in advance of expenditure, what factors must be considered in deciding on rates of depreciation, and what considerations must be weighed in rebuilding. The author has reduced his subject to mathematical relation to its parts, as far as possible, and has resorted to diagrams in order to afford ready reference to results. The subjects of the seven chapters which constitute the book are the following: I, Relation of Site and Building; II, Appreciation of Value of Land; III, Values Established by Building; IV, Depreciation of the Value of Buildings; V, Depreciation of Mechanical Equipments and Power; VI, Cost of Operating Buildings; VII, Manufacturing or Power Machinery. ConseIWa'ion by Sanitation. By Ellen H. Richards. New York: John Wiley&Sons, 1911. 8vo.; 305 pp. Price, $2.50. Compiled from the experiences of the past twenty years, “Conservation by Sanitation” takes the position that sanitation is as much a paying proposition as a railroad or a machine shop. It concerns itself with three of our greatest modern needs-good ail, good water, and the disposal of wastes. Under the present system of tight buildings, good air is by no means “free.” Air supply costs the modern householder one-fourth as much as his food supply, although its charges are disguised under the names of “went” and “fuel.” 'fhe average man perhaps finds it casier to !ealize the good and evil potentialities of water. The author's facts and figures in re- lation to water supply-its efficiency, protection, and regeneration—are abundant and convincingly marshaled. The interdependence of town and country is graphically shown in the panoramic view of a stream's pollution. Succeeding chapters are devoted to ways and means of purifying wat(r and disposing of contalninating ,astes. In conclusion we are given a series of laboratory notCH dealing with air and water tests and determination:, ' he volume is put forth as a lahoratory guide, but it has a simplicity, sinef'rHy and l'eadableness rarely found in the exposition of scientific snDjPcts, and the writer never loses sight of the vital relation of her mission to thc welfare and advancement of the masses. Science from an Easy Chair. By Sir Ray Lankester, K.C.B., F.R.S. New York: The Macmillan Company, 1911. 423 pp.; 84 illustrations. Price, $1.75 net. The volume before us is a collection of papers contributed by Sir Ray Lank"ster to the London Dally Telegraph. The modern thirst for scientific knowledge can UP no bettcr satisfied than by scientists themselves if they wlll only take the trouble to write down to the levd of the great reading public. 'o be sure, popular treatment usually means such simplification of expression that it is difficult to maintain sltlrict ,scientific acclll'ae'. It is given to but few mell to teach the multitude scientific trutbs in a way that the multitude can understand. If we may judge from this collection of essays, Sir Hay Lankestpr mlY be numbered among tb(He. His ('NSHYR a IP all of them so simply worded that any man with a high-sehOUl (ducation ean undprstund tllPl1l. Thc variety of subjects is great, ranging as it does from biology to astronomy, from meteorology to chemistry, from paleontology to 'dea t h Iltes." The Sugar Industry of Mauritius. A Study lin Correlation. Including a Scheme of Insurance of the Cane Crop Against Damage Caused by Cyclones. By A. “Walter, F.R.A.S. London: Arthur L. Humphreys, 1910. 8vo.; 228 pp.; illustrated. The work is in the nature of an iDvestigation into what the author terms the “conelative coefficients” between the cane crop of Mauritius and the meteorologieal elements. The investigation falls naturally under two headings: 1'irst, as to a m"thod of ,stimating the damage caused by cyclones, etc., and. second, a consideration of insurance against such damag(. Matters have now progressp( to the point where not only is an equitalJk insurance Of the crop possible, but also an insurance of the profits. A brief history of the agrieulture and cOlmeree of the island is included. How to Grow Vegetables and Garden Herbs. A Practical Handbook and Planting Table for the Vegetable Gardener. By Allen French. New York: The Macmillan Company, 1911. 8vo.; 312 pp.; illusLrated. Price, $1.75 net. This is a new edition of the bool, previously published under the title “The Book of Vegetables.” The writer confesses that at the earlier stages of his eareer as a rark(t gardener he might have avoided many costly mistakes and failures had such a reference book as this been in his possession. rJhe seasons and lthods given are for the northern United States and the latitude is that of New York. Each vegdahle or herb is first described and its uses given, after which such points as soil, moisture, proper planting distances, and methods of handling arc taken up. 'l'here is a table showing seed longevity and ounce values, and an index giving imnwdiatc access to any desired information. Modern Geography. By Marion 1. New-bigin, D.Sc. New York: Henry Holt&Co., 1911. 12mo.; 256 pp.; illustrated. Price, 75 cents net. “Modern Geography” is one of the issues of the “Home University Library of Modern Knowledge,” a commendable effort to continue the educative work of the serious magazine a rticle. After a short review of the beginnings of modern g(ography, surface relitf and the process of erosion is studied, together with ice and its action. Climate and weather is the subject of another chapter, followed by stUdies in plant geography and animal life. rhis brings us to the IlOst interesting division or the little volume-that dealing with the races of Europe and their origin. A discussion of minerals and their distribution in relation to industries and towns fittingly concludes the body of the work. A descriptive list of works of reference is an adjunct to be commended. Le Veri MeccanicIIe. Lora Calcolo e Costruzione. Manuale Teodco-Pratico ad Uso dei Cap i-offlcina me. Ind ustriali, Capitecnici, Ingegneri, Inseg-nanti di teenologie meccaniche nelle Scuole Industriali e d'arti e mestieri, Tornitori, Fabbri, Alunni di Scuole industriali. Milan: Ulrico Hoepli, 1911. 12mo.; 215 P].; 110 cuts; 48 tables. Tbe title and the suh-titles form a suff-ciently eloquent notice of tIl<' little work. which bas the clear print and profuse illustration that distinguish the Ioepli handbooks.