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look on while our million and a half is squandered by directors who now confessedly are to be men without business knowledge of the industry they control."

If we would take advantage of the great opportunity which this war affords for industrial and economic rearrangements, it is imperative that the ruling classes in this country should no longer continue in their present state of semi-education which passes as culture, and which permits them to go through life with little or no understanding

of the vital importance of science to the State. If after the war we are to recover some of the chemical industries which we have lost, and even maintain those which we still possess, it is essen tial that the individual undertakings should be controlled by men who have a real and expert knowledge of the business in which they are engaged, and that our legislators should have had sufficient scientific education to enable them to understand such problems connected with these industries as may be brought before them. The experience of the past thirty years points unmistakably to the conclusion that industrial success is becoming more and more dependent upon the co-ordination of industrial effort, and the embarrassing position in which we find ourselves at the present moment, in respect of the supply of a number of chemical products, is largely attributable to the almost entire absence of any such organisation. In both France and Germany we understand that councils of experts have been appointed to inquire into the effects of the war on the chemical industries of these countries, and to report to their respective Governments as to what legislative measures are desirable for promoting their welfare. As the present crisis is on a scale which we trust may never recur in the history of the world, so the opportunity for discarding mischievous traditions, effete ideas, and clumsy methods of procedure is of such an altogether exceptional character that it is to be hoped. we shall not allow it to pass unutilised through ignorance, lethargy, or divided counsels.

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and public circles, as several of the British food manufacturers of repute have availed themselves of scientific help for some years past, and it may be claimed that the high-not to say world-wide -repute of the products of some of these firms is to some extent due to the resource of, as well as the control exercised by, their scientific staff. In the United States, legislation has been very largely the cause of the awakening of the public interest in its food, and in this connection the with gratitude by present and future generations. name of Dr. H. W. Wiley will be remembered

Whatever the cause, the development of the investigation of the composition and value of food products has been exceptionally rapid during the past few years: it is manifested by such outward signs as the foundation of university chairs in food chemistry in America, and the publication of

informative text-books.

As the moment is ripe for reform, the wisdom of founding such a chair at our own Imperial College of Technology may be urged: there is much to be done, for example, in educating the public as to the food value of many low-priced products from our Colonial Empire, which are at present neglected, and in showing manfacturers how to make better use of the available raw material.

Dr. H. C. Sherman, who occupies the chair of food chemistry at Columbia University, has produced an exceptionally informative book, in which he combines an account of the production and preparation of the various food products for the market, with statistical data, details as to their chemistry and physiology, and an outline of the latest scientific research and opinions.

The book also contains a large number of upto-date tables giving the food values, protein content, and mineral constituents of all sorts of foods, and is, indeed, replete with information of every kind, so that it will be indispensable to All the every food chemist and manufacturer. principal food products are dealt with in turn, each chapter being concluded with a list of references to the literature. Though much of the information given is outside the ordinary scope of the college trained chemist, it corresponds exactly with the practical details which the actual worker requires, and we do not remember to have seen this given so succinctly anywhere else. The more advanced scientific sections are equally satisfactory, so that current views are expressed without undue dogmatism: this is especially the case in the more physiological sections.

A good deal of space is devoted both in an appendix and elsewhere to the rules and regulations for the enforcement of the Foods and Drugs

States, and how much each of these crops is worth; that America eats wheaten bread, and that the inhabitants of the "Old World" subsist on wheat, corn, and rice. Beside some useful general information, he will find a chapter on lawns, and a page or two on sand-binding grasses.

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Act in America. These are of great interest to the British reader in view of the possibility of more drastic food legislation here, though fortunately the sale of inferior food materials is not tolerated to anything like the extent that existed in America. It is commonly understood that the most drastic legislation was necessary there to combat the existing evils, although its severity has to some extent acted in restriction of trade. In any case, such movement here should be official and under the guidance of responsible scientific opinion, and not sponsored by irresponsible

"Pure Food Institutions."

The university courses of study are already so crowded that there is no time for the introduction of food chemistry into the degree course, nor, indeed, is such desirable. The would-be chemist, if he is to play his part in building up British industries, must be trained as a chemist first and as a specialist afterwards. Books such as this will be of the utmost service at the stage when the young chemist has to act on his own and to take responsibility. Prof. Sherman has done a great service to his colleagues. From the point of view here developed it is to be hoped that. he will compress rather than enlarge future editions, so that the book may be read and not consulted as a dictionary. E. F. A.

APPLIED BOTANY. (1) A Text-book of Grasses, with Especial Reference to the Economic Species of the United States. By Prof. A. S. Hitchcock. Pp. xvii +276. (New York: The Macmillan Co.; London: Macmillan and Co., Ltd., 1914.) Price 6s. 6d. net.

(2) A Manual of Weeds. By A. E. Georgia. Pp. xi+593. (New York: The Macmillan Co.; London: Macmillan and Co., Ltd., 1914.) Price 8s. 6d. net.

(1).

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LTHOUGH we are disposed to welcome any innovation in the planning of textbooks of applied science, we cannot congratulate the author of the work under review on the scheme which he has adopted. He divides his book into two parts, and treats first of economic agrostology, and subsequently, of systematic agrostology. As a consequence, the student who begins the book at the beginning reads of a considerable number of grasses, mostly called by their popular names, and if he be a novice, he must pause at each page to look up, in the systematic part, what these names signify. Moreover, whether he be novice or adept, he will find but little information of real value in the economic section. He will discover how much corn and wheat and barley and other cereals is grown in the United

It may be that this somewhat discursive treatment is all that is possible in the present stage of "economic agrostology"; but whether it be so or no, we feel convinced that the proper place for it is at the end and not at the beginning of the volume.

Part ii. opens with an account of the morphology of the vegetative and floral organs of grasses. The descriptions are terse and clear, but their value is reduced very materially by the fact that not one figure is given by way of illustration, neither of the vegetative organs nor of the somewhat difficult inflorescence and flower. This is the more remarkable in that the succeeding taxonomic chapters are well and copiously illustrated.

The experience of the reviewer convinces him that it is impossible to teach the systematic botany of grasses unless the student has first mastered thoroughly the floral morphology of typical forms, and doubt may be expressed whether such mastering may be obtained by merely following the written text.

The taxonomical section, which occupies nearly half the book, follows in part the classification adopted by Bentham and Hooker, and, with respect to the "tribes," that of Hackel. The code governing nomenclature is not that laid down in the Vienna rules, but is "The American Code of Botanical Nomenclature.” To criticise this decision scarcely becomes a non-American reviewer, but he may express a regret that systematists cannot come to a general agreement which will prevent these games of nine-pins with names. For example, all the gardens of Europe know Pampas grass by the name Gynerium argenteum. In this book it is called Cortaderia argentea, and no indication is given whether Gynerium argenteum is synonymous with C. argentea, or whether the latter is another plant under the same common name. Buffon said long ago that it was easier to learn botany than botanical nomenclature. The systematists seem to take a joy in maintaining the truth of the aphorism.

(2) M. Boutroux has insisted recently that sentiment no less than will and intellect must be reckoned with in the psychological make-up of mankind. No one who has fought with weeds, whether in the farm, the garden, or the golf-green will doubt it. The fight was stubborn and its fortunes varied, but whether won or lost, the

weeder left the field with a deep respect for his adversaries: so stubborn is the resistance that they offer, so various are the means by which they evade extermination.

Here they all are, hundreds of them catalogued and described in this book, and although the weeds treated of are those which trouble the American cultivator, the English farmer and gardener will recognise many of his old foes. He will also learn not a little of new ways of fighting them. For America takes its weeds seriously-more seriously even than the good farmer of this country. He tracks them to their lairs in the hedgerows and keeps a sharp lookout on them in his neighbours' plots. He even invokes legislation upon them. He needs be vigilant indeed, for field labour is not cheap or plentiful in his country, and the chief means of combating weeds-constant cultivation-cannot always be practised. We confess to a certain feeling of unmalicious pleasure, like that we have in the misfortunes of our friends, when we saw the weediness of the fields of certain parts of North America. Nevertheless, the American will win in his fight with weeds; for he threatens them with all the resources of organic chemistry. Not only are the sulphates of iron and of copper pressed into his service as weed-killers; but, and more recently, weeds are being attacked with fine sprays of kerosene or crude petroleum.

The author of this manual writes with sureness on her subject. She knows weeds well, describes them admirably, and gives much sound advice on the methods to be adopted for their eradication. In fact, this is the best book yet published on weeds and one that will prove of considerable service to cultivators in this country. High praise must be given also to F. Schuyler Mathews for the excellence of the 385 illustrations. Their value is enhanced by the fact that they face the page of text on which they are severally described.

One suggestion only would we offer in the interest of the busy reader of the book: that a new edition should include an appendix in which the means of control, and weeds controlled by these means, are classified.

LANTERN- AND MICRO-PROJECTION. Optic Projection Principles, Installation and Use of the Magic Lantern, Projection Microscope, Reflecting Lantern, Moving Picture Machine. By Prof. S. H. Gage and Dr. H. P. Gage. Pp. ix+731. (Ithaca, N.Y.: Comstock Publishing Co., 1914.) Price 3.00 dollars.

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tional treat to see a magic lantern entertainment, but now there are kinematograph theatres in all our main streets, and lanterns for the teaching of history, geography, and science in our schools, so that the younger generation look upon the fantern as a matter of course, and even the poorest of them go (perhaps too frequently) to the picture palaces.

The number of operators using the lantern has thus enormously increased in the last few years, and the lantern is acquiring quite a literature of its own. The volume under review treats the subject very fully, and collects into one volume a large amount of valuable information on every aspect of the subject. It is intended to be available to the ordinary unscientific rule-of-thumb operator, as well as to the manufacturer, and to the unscientific demonstrator or student. Το meet the needs of the first of these, plain, practical directions are given in the earlier part of the book for using the direct-current arc, the alternating arc, the miniature arc, the lime-light, etc.; also practical summaries of what to do and what to avoid are added to each chapter, and there are similar practical instructions for using sunlight with a heliostat, for projecting opaque objects, for micro-projection, the kinematograph, and many other applications of the lantern. sumably with the idea of making each section complete in itself, there is a great deal of repetition in these chapters. This will probably be of advantage to the practical man who is interested only in one form of projection, but it makes this part of the book tedious to read.

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In the later part of the book there are many valuable tables and curves giving, for instance, the relations between current, voltage, and candlepower of the different forms of arcs and their distribution of light intensity; also the light and the energy absorption of the various mediaglass, water, etc.-that are used in projection apparatus; and the reflecting powers and light distribution of lantern screens.

In the last chapter are some applications to physics. We should like to have seen this further developed; brief as it is, it explains how to demonstrate some beautiful experiments in advanced optics-experiments which are not often shown.

The instructions for adjusting the radiant are somewhat misleading. It is said that it should be placed at the principal focus of the first section of the condenser (§ 55), and it is said that there is a loss of light if the lamp is brought nearer. In almost every case this is not so, a bigger cone of light being embraced; in practice the second lens of the condenser is not made

a weak lens, but the lamp is pushed up within the focus of the first lens, and it is very rarely that an operator changes his condenser when he changes his objective, as laid down in § 89.

(2) The science of pedagogy is arousing increasing interest in this country, although, curiously enough, less among those engaged in teaching at our public schools than at primary and other secondary schools. But the literature of the subject has received comparatively few British contributions. The object of the author is, in his own words, to summarise the anthro

The only other criticism is that in projecting the rings and brushes in convergent polarised light, the objective does not focus the back lens of the second convergent system on the screen, but its back focal plane; this mistake is, how-pological, experimental, pedagogical, psychoever, generally made in the optical text-books. It should be added that there is a useful bibliography and a copious index.

MATHEMATICAL WORKS.

(1) Elements of Geometry. By S. Barnard and J. M. Child. Parts i.-vi. Pp. ix + 465. (London: Macmillan and Co., Ltd., 1914.) Price 4s. 6d.

(2) A Foundational Study in the Pedagogy of Arithmetic. By Dr. H. B. Howell. xi+328. (New York: The Macmillan Co.; London : Macmillan and Co., Ltd., 1914.) Price 5s. 6d.

net.

(3) Constructive Text-book of Practical Mathematics. By H. W. Marsh. Volume iii. Technical Geometry. Pp. xiv +244. (New York: J. Wiley and Sons, Inc.; London: Chapman and Hall, Ltd., 1914.) Price 5s. 6d. net. (4) Algebraic Invariants. By Prof. L. E. Dickson. Pp. x+100. (New York: J. Wiley and Sons, Inc.; London, Chapman and Hall, Ltd., 1914.) Price 5s. 6d. net.

(5) Plane Trigonometry and Tables. By G. Wentworth and D. E. Smith. Pp. v+188. Trigonometric and Logarithmic Tables. By G. Wentworth and D. E. Smith. P.p. v+104. (London: Ginn and Co., 1914.) Price 5s.

(1) Tauthors, well-known text-book entitled THIS

HIS is not a modified edition of the

"A New Geometry for Schools." In form, grouping, method, and to some extent, subjectmatter, it differs widely from their former work. The experience gained from eleven years' teaching on modern lines has led them to certain conclusions which they embody in the present volume. To some extent, they revert to older methods, as, for example, in the treatment of parallels, tangents, the early theorems of the second book of Euclid, and the grouping of cognate theorems. In other respects they adopt a more radical position by introducing trigonometrical ratios and sections on solid geometry (mainly numerical) at an early stage. They have compressed an immense amount of matter into a compact form, and the array of numerical and theoretical exercises is almost alarming in its

extent.

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genetic and phylogenetic resources now available, which bear on the part arithmetic should play in a scientific curriculum. His investigation is fourfold (1) genetic, (2) psychological, (3) statistical, (4) didactical. Not the least interesting and valuable part of the book is the account of experiments, arranged and conducted by the author on the determination of ability in number apprehension and fundamental processes.

(3) It is strange to pick up a text-book on geometry and fail to find a single diagram before page 150. The explanation lies in the fact that the author believes that each student should, by his own researches, write his own text-book. That such a mode of procedure as is indicated by the plan and structure of this book has been in operation for nearly twenty years is conclusive evidence of the enthusiastic personality of the author: that many teachers, however, could adopt his method seems to us highly improbable. His purpose is to enable each pupil to build up for himself a logical geometrical structure, by the aid of appropriate suggestions made at the right time. The form these are to take and the quality of the work expected of the pupil is set out in great detail. We doubt, however, whether the author will make many converts.

(4) This monograph provides a simple and admirable introduction to the theory of invariants of algebraic forms. It is divided into three parts. The first deals with linear transformation from the point of view of (1) change of axes of reference, (2) projective geometry. Jacobians and Hessians are discussed, the latter in connection with the solution of the cubic and the points of inflexion of a cubic curve. The second treats of algebraic properties, such as weight, annihilators, reciprocity, differential operators, etc. And the concluding section introduces the symbolic notation of Aronhold and Clebsch. Some carefully selected

sets of examples are provided.

(5) The form and plan of this text-book indicate that the changes in the teaching of elementary trigonometry have taken place along similar lines on each side of the Atlantic. The practical aspect of the subject is now regarded as requiring chief emphasis in the early stages and the abstract theory is postponed. Considerable space is de

voted to applications involving only the use of the right-angled triangle; and identities occupy a subordinate position. The final chapter deals with complex quantities, Demoivre's theorem, and applications to analysis. The last hundred pages of the book are taken up with logarithmic and other tables, calculated to five figures. The first-rate quality of the type employed deserves special mention.

OUR BOOKSHELF.

Experimental Studies in Electricity and Magnetism. By F. E. Nipher. Pp. 73. (Philadelphia: P. Blakiston's Son and Co., 1914.) Price 1'25 dollars net.

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THIS book consists mainly of descriptions of the author's experimental work, and summarises his reasons for accepting the one-fluid theory of electricity. Photographs of discharges across spark-gap, and traces on a photographic plate due to discharges over its surface, constitute the major part of the evidence. Much work has been done, and many interesting plates are reproduced, but it is doubtful whether the experiments are quite so conclusive as the author believes. Several novel ideas are introduced, such as the existence of conducting lines or "drainage channels" round the positive or "exhaust" electrode in every kind of discharge, though it might be pointed out that this idea of a well-conducting channel is scarcely compatible with the considerable potential-slope which exists in the positive column of a discharge tube. The suggestion that gravitational attraction is due solely to the puscular nebula" which permeates all matter is also novel; it is used to explain the explosive effect of discharging a Leyden jar through a wire.

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Loosely-worded expressions as "the corpuscular nebula is set into a rhythmical vibration" abound, and the phraseology generally is scarcely so precise as that usually found in scientific publications. It is possible that the case made out by the author suffers considerably from the manner in which it is presented, but certainly simpler explanations than those given would seem to suffice for some of the phenomena mentioned. The deflection of a magnetic needle due to a gust of wind might conceivably be due to a magnetic storm produced by the wind, but it would be advisable to see that the oscillation box is hermetically sealed or even evacuated, before accepting the magnetic storm hypothesis!

The Principles and Practice of Judging Live Stock. By Prof. C. W. Gay. Pp. xviii +413. (New York: The Macmillan Co.; London: Macmillan and Co., Ltd., 1914.) Price 6s. 6d.

net.

THIS volume is a very full compendium of all that belongs to a practice which has almost become a fetish in American agricultural colleges. To the student is given a card on which are printed the sections into which a horse, or some

other animal, may be divided, and the marks to be awarded to each section. A draught horse, for instance, is divided into forty sections, and, as the marks total to 100, most sections get very small and none very large marks. The marks for some of the most important parts are these, given shortly: hocks, 6; hind cannons, 2; hind fetlocks, 2; hind pasterns, 3; hind feet, 4; hind legs, 4; walk, 6; trot, 4.

Some of us who have tried it would have been exceedingly glad had this volume contained some evidence as to the educative value of the score card, because it may be doubted whether good judges are produced by its use; and because it fails to make sufficient distinction between the good and the supremely good, or the fair and the All this, however, is rather a criticism of the system, or at any rate, of the scale of marks.

useless animal.

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The Elements of Electro-Plating. By J. T. Sprague. Pp. vii+72. (London: É. F. N. Spon, Ltd., 1914). Price 1s. 6d. net. THE publication of this little volume brings home to us the sparseness of literature on the subject of electro-plating. Its publishers have have considered it worth while to re-publish, in this form, the intensely practical and well-written chapter dealing with the practice of the electro-deposition of metals which originally appeared in the late Mr. J. T. Sprague's "Electricity: Its Theory, Sources, and Applications." This classic was one of the best books of its kind when originally written, and the chapter on electro-plating was one of the best parts of the book. It is true that it is addressed "rather "rather to experimentalists, students, and general readers" than to those "mainly intent on business considerations," and it is also true that as good electro-plating was done twenty-five years ago as now; yet one cannot but feel that the publishers would have done better to publish a new book than to re-publish an old one when dealing with a practical application of electricity. The reprint bears the new date 1914, and not the date of original publication, but perhaps some of our older readers may be able to make a rough guess at the latter from the clue given by the following passage: "It is impossible to urge too strongly, alike upon the learner and the practical operator, the advantage of keeping in circuit a suitable galvanometer.. and galvanometers to show current in amperes are now easily obtainable." The book, old as it is, contains valuable directions and recipes, and if, instead of merely reprinting it, the publishers had employed a practical man of to-day to revise and re-write it, they would have deserved our unstinted commendation.

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