DR. H. STROUD'S Apparatus for DETERMINING THE The Resonance Tube is 3 ft. long, with a graduated scale fixed at the side. The sliding reservoir moves easily in a grooved frame, so that the water level can be quickly altered. Price, in Polished Mahogany Stand, 24/ SOLE MAKERS BRADY & MARTIN, LTD., Scientific Apparatus Makers, NEWCASTLE-UPON-TYNE. Makers and Dealers in all kinds of Chemical and Physical Apparatus for Schools and Colleges, Works' Laboratories and Special Research Work. CONSTRUCTION OF NEW FORMS OF APPARATUS UNDERTAKEN. Write for Circular. VOLUMETRIC Verified and Stamped NATIONAL PHYSICAL LABORATORY. JOHN J. GRIFFIN & SONS, Ltd., SARDINIA STREET, LONDON, W.C. The newest and best books of popular interest are added as published. The books are delivered to the Bookstalls to Subscribers' orders, carriage paid. Over 800 branches to which Subscribers can be trans. ferred. Special Travelling Subscriptions entitling Members to exchange at any branch without previous notice. Terms on application. Books exchanged by Parcels Post, Rail, or other means from the Head Office to any part of the United Kingdom. Boxes supplied gratis. Prospectus and list of recent books in circulation and any other information can be obtained upon application. A catalogue of Surplus Library and New Remainder Books, offered at greatly reduced prices, is published monthly, and supplied gratis on application. HEAD: 186 STRAND, LONDON, W.C. OFFICE: THURSDAY, JUNE 22, 1905. THE CHEMISTRY OF PLANTS. Biochemie der Pflanzen. Vol. i. By Prof. Friedrich Czapek. Pp. xv+584. (Jena: Gustav Fischer, 1905.) Price 14 marks. THIS HIS work forms a new type among those on physiological botany: in some degree it resembles "Die Pflanzenstoffe " of Husemann and Hilger, and "Die rohen Stoffe des Pflanzenreiches " of Wiesner; but whereas the bias of the former is pharmacological, and that of the latter economic, the subject is treated in this volume more from the chemical standpoint. The author states that his book is not to be regarded as a treatise or handbook for students, but as a work for reference, and that he has endeavoured to show in it what results the application of chemical methods to the problems of botanical physiology have yielded. The subject-matter is divided into three parts-a historical introduction of 19 pages; a general part of 62 pages; and a special part of 489 pages. The general part is divided into two chapters, dealing respectively with the substratum of chemical processes in the living organism, and with the processes themselves. The first chapter treats of protoplasm and its constituents, colloids. then protoplasmic structures and their biochemical import; the second of reactions from the standpoint of general chemistry, a survey of the conditions of reactions, ionic reactions in the living cell, the velocities of reactions, catalysis, the general chemistry of enzymes, cytotoxins, and similar substances being here made. The special part is concerned with the occurrence, metabolism, and metastasis of aliphatic substances in detail. The general arrangement of this part is in the first order chemical: the first section is devoted to fats, lecithins, phytosterins, and waxes; the second to carbohydrates, commencing with the simpler sugars, and ending with the substances forming the skeletal structure of plants. In the second order the arrangement is mixed; the chapters deal in part with the taxonomic, in part with the morphological, anatomical, and histological distribution of substances, and further with the physiology of the various bodies considered. Photosynthesis receives considerable attention, and is regarded in all aspects; in connection with it the physics and chemistry of chlorophyll are discussed at length, and other pigments are also dealt with. The treatment of the physics and chemistry of starch is also fairly extensive. An index of the subjects and authors will be given at the end of the completed work. The general nature and structure of the book having been reviewed, passage to criticism of it will now be convenient. A work of this kind, involving the two main ideas of chemistry and plants, requires, if it is to yield its full value, so to be arranged as to enable the composition or metabolism of a plant (in so far as this is known), as well as the distribution of a substance or a process, to be ascertained with equal ease. But this is not the case with this work owing to its arrangement; the mode of treatment is analytic rather than synthetic. In "Die Pflanzenstoffe" one volume deals with the material from the chemical, the other from the taxonomic standpoint; but this method, although very convenient, necessitates duplication. The difficulty could have been here met through use of a suitable and strictly methodical arrangement, had the divisions of various orders of magnitude been formed from different standpoints, and had those which constituted each order been of similar kind and value. The end can be still attained here by aid of a copious and well-arranged index of the subject-matter. Printers' errors are not very numerous, and occur chiefly in the earlier part of the book. Discrepancies and slips of the pen are noticeable here and there. For example, on p. 7 Priestley is given as the discoverer of oxygen, but on p. 12 Scheele; on p. 144 anaërobem should be aërobem; Bedeutung on p. 434 should be Beleuchtung. From the structure of a sentence on p. 39 one might suppose that ethyl-ether was insoluble in water. Further, the last paragraph on p. 313 is hardly consonant with the author's apparent acceptation of Meyer's hypothesis of the structure of starch-granules on P. 312. Since the work is one for reference, hence a com pilation, and since the author has intentionally almost entirely avoided critical remarks on the subject-matter, the reviewer can only consider the selection from a critical standpoint. It may be said, on the whole, that the selection has resulted in a very representative collection of diverse opinions on controverted questions, and in many cases almost an exhaustive one. As a result of this, condensation is, in the case of many papers, extreme, and at times there is omission; but this is almost a necessary consequence of the mass of literature consulted. One disadvantage, which is, however, common to all books of this class, is the slight indication of the relative values of the various works cited; all emerge with equal distinctness, except in so far as more space is given to some than to others; beyond this clue there is no guide to their relative worth. This is well shown in the case of the chemistry of starch and some of the pigments; a chemist or botanist who had not devoted any special attention to these substances would rise from a perusal of the epitome here given under the impression that there was only chaos. In connection with the chemistry of starch the author does not seem to have had at hand all the works of H. T. Brown and his collaborators, G. H. Morris and J. H. Millar, or to have grasped their views quite clearly. Enzymes are stated to be colloidal catalysors, and their colloidal state is said to be of import. In the opinion of the reviewer there is no sufficient evidence to show that any enzyme is a colloid, and, indeed, considerable reason why many should not be so. There is even no sufficient evidence that enzymes are chemical compounds; they may be essentially mixtures, or merely functions of special conditions. In the consideration of the action of accelerators and retarders on amylohydrolysis, there is no mention of Ford's recent work. to give a purely dynamical explanation of everything. A striking example of this tendency is Maxwell's Cytase is stated not to occur in resting seeds, but dynamical theory of the electromagnetic field. it is present in small amounts in some. of In giving directions for the preparation Schweizer's solvent for cellulose, the best method, that of dissolving metallic copper in ammonia through which a current of air is passed, is not mentioned. The function of a critic is to criticise; but he is human, and hence prone to eulogise-or blame. In this case the reviewer can only yield praise. The work fills a void that botanical physiologists have long felt. The wealth of material dealt with is surprising, and the expenditure of labour must have been enormous. There is very little evidence of partiality, whether national or of other kind. The compass of the work is wide, and it is thoroughly up to date. The reviewer was especially pleased with the general part. For the first time in a botanical work adequate stress is put on the importance of colloids as such, and on the necessity of knowledge of their nature for progress in physiology; and for the first time the principles of general chemistry are given the position due to them in a work of this class. To Prof. Czapek for having done this all botanical physiologists must remain indebted. In the opinion of the reviewer the value of the work would have been enhanced by incorporation in it of would have been enhanced by incorporation in it of curves illustrating the various processes described, and by citation of mathematical expressions wherever they have been proved or found to be applicable. If the work should run through subsequent editions, as is most likely, it would certainly be best for different authors to be delegated for various parts, since with the rapid accumulation of material it will be impossible for a single author to deal adequately with a work of such dimensions. F. ESCOMBE. soon Electro In 1881 it was shown by Prof. J. J. Thomson that a particle charged with electricity possesses some inertia due to its electric charge in addition to the As the result of ordinary inertia of the particle. Kaufmann's measurements, we now know that all the inertia of an electron is of this electromagnetic kind. It is now further suggested that all matter is composed of electrons, so that all inertia is electromagnetic. Density, according to this view, is simply number of electrons per unit volume. magnetic inertia, that is, all inertia, is due to the energy of the magnetic field produced by the moving charge of electricity. The energy of this magnetic field resides in the ether. According to Maxwell's dynamical theory, the electromagnetic energy of the ether is due to motion of parts of the ether, these parts possessing inertia. But the only kind of inertia which we really know is the inertia of matter, which is due to the electromagnetic action of the electrons of which matter is made up. If inertia is due to electrons, then if we ascribe to parts of the ether the property of inertia we ought to say that the ether contains so many electrons per unit volume. But the free ether is not supposed to contain any electrons; in fact, if we explain inertia by the energy of the magnetic fields produced by moving charges, then evidently to explain this energy by inertia in the ether is merely to argue in a circle. The position is, then, that inertia is explained in terms of the electromagnetic field, and that now some explanation of this field is required not involving inertia at all. far, no such explanation has been offered. Larmor has suggested that the ether has an enormous density or inertia per unit volume, and that it moves along the lines of magnetic force. This explanation must evidently be abandoned if matter is regarded as made up of electrons having only electromagnetic energy, or else we must say that the ether has a sort of inertia, not the same as the inertia of matter, but like the kind of inertia matter was supposed to have before the electromagnetic theory of inertia was put forward. So To say this, however, is merely to ascribe to the ether a property the definition of which is that it explains what it is required to explain; it is, in fact, merely the old process of " explaining" a thing by inventing a name for its explanation. The properties of the ether, then, expressed by Maxwell's system of equations are at present without any explanation, but they have taken the place of inertia as the funda mental thing in terms of which phenomena are to be explained. In these circumstances the appearance of Dr. Bucherer's small volume on "Elektronentheorie " is exceedingly opportune. It contains a concise and readable account of Lorentz's splendid theory and of the electromagnetic theory of inertia. The introduction gives a short account of the properties of kathode rays and radium radiation, which, of course, are the properties of electrons on which the electronentheorie is based. Chapters i. and ii. contain a short account of Lorentz's theory for bodies at rest, and chapters iii. to v. the theory for moving charges, vector analysis being used throughout. The remaining chapters deal with radio-activity, rotating charges, radiation from electrons, the Zeeman effect, the theory of Röntgen rays, aberration, and dispersion. The mathematical theory of the properties of electrons appears to be well and clearly dealt with on the whole, and the author has managed to compress a great deal of information into a small space. English readers will probably feel that sufficient credit is not given to some English physicists to whom the initiation of the whole theory is really due. The parts of the book dealing with experimental facts and the theory of things outside the electromagnetic theory are rather superficial and sometimes erroneous. example, it is stated that the radio-activity of radium emanation diminishes very rapidly with rising temperature, and that this can be deduced thermodynamically from the large amount of energy evolved. This glaring error shows conclusively that the author's acquaintance with the literature of radio-activity is of the slightest. The book will no doubt be welcomed by many anxious to learn about the new views on inertia and matter, and to such it should prove useful. (2) Dr. H. Starke's book on experimental electricity and magnetism contains a very up-to-date and excellent elementary account of the subject. The explanations of many of the experiments described seem scarcely full enough to enable students actually to work from them, but it is evidently not intended that they should do so without further help. Many good diagrams of modern forms of apparatus are given. It cannot be said that the author has succeeded in giving that warmth of colour to his account which characterises Mr. Casey's charming book. But since that impression was formed the present writer re-visited the Riviera, and the feature which he most noticed was how exactly every minute detail tallied with Prof. Strasburger's descriptions. The information contained in this book is just what is wanted to make a visit to the "Côte d'Azur " both enjoyable and instructive. A large proportion of the text is taken up with historical accounts of the various cultivated plants and trees growing in the district. The most characteristic vegetation of the lower valleys-the vine, orange, lemon, olive, fig, cypress, and palm-is largely the reForsult of "alien immigration." Before the hillsides were carefully terraced and cultivated they were overgrown with small scrub or "maquis (Italian "macchia ") consisting of pines, rosemary, myrtle, tree heath, three species of cistus, mastic, juniper, the characteristic spiked lavender (Lavandula stoechas), the remarkable spiny euphorbia (E. spinosa), and a number of other plants too numerous to mention. The aromatic perfume of many of these plants is one of the most salient features of the "maquis." In Prof. Strasburger's description of this characteristic undergrowth, the word " Duft " (perfume) occurs over and over again. It is only after walking through such vegetation that one realises that this very repetition makes the description all the more accurate and realistic, and readers of the book will do well to bear in mind the fact that each occurrence of the word usually refers to a different scent. Prof. Strasburger's descriptions of the "maquis " mostly refer to Antibes, where a considerable area of this primitive vegetation still remains untouched. In many places along the coast the "maquis" is being rapidly cut down to make room for unlovely vineyards, and the face of the country is being made less beautiful. (3) Dr. F. Bremer's book on physics for the upper classes in schools is a rather bad type of school textbook in which it is sought to make things suitable for school children by giving very short and scrappy accounts of everything. It looks like a book which might be useful to a student with a very good memory in cramming for an elementary examination in physics. He might get through the examination, but he would have learnt nothing worth knowing. HAROLD A. WILSON. A BOTANIST'S RECREATIONS ON THE Streifzüge an der Riviera. By Eduard Strasburger. THE HE Riviera has of recent years become regarded as the playground of wealthy people whose only idea of enjoyment consists in spending hours in the unhealthy atmosphere of the casino at Monte Carlo, raising dust with a motor-car, dining at separate tables, or sitting in an hotel lounge. But such people see nothing of the real Riviera, with its wealth of wild flowers, its charming rock villages perched on heights, its olive, orange, and lemon groves, and its torrent beds up which one scrambles from rock to rock, passing a succession of pretty pictures each prettier than the previous one. On first reading Prof. Strasburger's book, the reviewer formed the impression that the descriptions were too prosaic and wanting in sunshine. Considerable space is devoted to a description of the gardens at La Mortola, and the scent manufactories at Grasse also occupy many pages. In reading these descriptions one cannot help regarding the author somewhat in the light of a walking encyclopædia. He gives long digressions on the manufacture of chemical perfumes in connection with Grasse, and he makes his account of Sir Thomas Hanbury's garden the opportunity for giving much historical information about many economic plants such as the tea, coffee, and cocoa plants the sugar-cane-and, thence, the introduction of beet-sugar, the ebony and the camphor tree which can hardly be regarded as the characteristic vegetation of the district. On the other hand, several interesting features are mentioned which a casual visitor might overlook. The characteristic flora of Hyères and the comparative absence of dust in the Esterel mountains are associated with the remarkable difference of geological formation as compared with the more frequented and fashionable but dustier winter stations in the limestone districts. The nightly concert of green frogs to which the author alludes is a sound which brings the Riviera vividly back to everyone who has heard it. On the whole, Prof. Strasburger seems to have devoted most of his attention to studying the plants growing in gardens and near the towns, and he does not describe many scrambles up into the distant mountains. But of the wild flowers to be found on the hillsides or up the torrent beds no better guide could be afforded than the beautiful series of coloured illustrations distributed throughout the text. It is possibly a pity that the figures are mostly printed with black outlines, and it might be thought preferable to have them printed on plates instead of mixed up with the letterpress. In addition to flowering plants, a number of the characteristic seaweeds have also been illustrated, and several charming little sketches of Riviera coast scenery, in the form of headings to the descriptions of the five different holidays spent by Prof. Strasburger on the Riviera, are a welcome addition. All these illustrations have been tastefully drawn and coloured by Fraülein Reusch. G. H. BRYAN. INTERNATIONAL PHYSICS. Recueil d'Expériences élementaires de Physique. By Henri Abraham. Part ii. Pp. xii+454. (Paris: Gauthier-Villars, 1904.) Price 6.25 francs. WE have already reviewed the first part of this col lection of physical experiments, which has been gathered together under the auspices of the French Physical Society. A large number of physicists from all over the world have participated in the collaboration by sending both descriptions of experiments and bibliographical references, and the editor's work has consisted in giving as much homogeneity as possible to the products of this multiple collaboration. The present and concluding part embraces the subjects of acoustics, optics, electricity and magnetism. On the whole, the experiments in this part are of a more difficult and elaborate kind than those previously described. This is to some extent, no doubt, due to the nature of the subjects treated. General manipulation and mechanics required less reference to be made to complicated and expensive apparatus than the subjects considered here. As a consequence of this the private student who has no access to a properly equipped laboratory will find much greater difficulties in his way. He will still find a field for work in acoustics and light. With a few springs and wires a considerable amount may be done in sound; and, in the experiments on light, homely articles like pins and champagne bottles are freely made use of. But in electricity and magnetism he must be prepared for greater outlay in apparatus. We lay stress on this point, because in our previous reference we recommended the book strongly to the private student with a taste for practical mechanics. The present part will be found of greatest utility to the schoolmaster eager for hints in the arrangement of class and lecture experiments. One special feature in the descriptions is that in most cases the dimensions of the apparatus which have been found to work well are given. This will certainly save a teacher a great deal of time, which otherwise he would need to spend in experimenting himself in order to discover the suitable size and shape of his apparatus. We do not hesitate to say, however, that time so spent is never lost, and if in the busy workaday world of the teacher some means for saving of time is essential, it has its disadvantages. It is usually only by the somewhat laborious method of trial and error that one learns the conditions neces sary for success. There does not seem to be much in the volume which is absolutely novel as regards style of experiment. The aim, obviously, has been to describe as simple experi ments as possible illustrative of all the common laws of physics. This description is in all cases very brief. There is no introduction of theoretical considerations; nor is there any attempt to make the subject attractive to a general reader. A figure, a short account of the construction and mode of using the apparatus-that is all. In some cases the suggestions are open to criticism in minor details. Thus, vibrating springs, which ought to be attached to a fairly solid support, are shown screwed to a slender skeleton wooden box. But in the main the suggestions seem excellent, and there are few teachers who will be able to learn nothing from them. The diagrams are not always clear; nor are they such as to give the book an attractive appearance. Briefly, the collection is meant for the teacher and not for the student. To the former it is commended, with the hope that he will be able to give life to these somewhat dry bones by instilling his own individuality into them. LIGHT AND HEALTH. The Effects of Tropical Light on White Men. By Major Charles E. Woodruff. Pp. vii+358. (London and New York: Rebman, Ltd., 1905.) Price 10s. 6d. net. THE title of this book gives little idea of the enor mous field traversed by the author, or of the amazing conclusions at which he has arrived. We understand that the work is intended for laymen as well as for medical readers, and particularly for Americans about to reside in the Philippines. No exception can be taken to the advice given by Dr. Woodruff in his concluding chapters. The necessity for opaque white clothing, and of sufficient protection to the head; the paramount importance of the siesta, and of avoidance of work and social functions in the middle of the day are recognised by Europeans living in the tropics. The suggestions as to the selection of suitable recruits for the army in the Philippines are admirable. But it is impossible to accept many of Dr. Woodruff's deductions from the scientific observations which he so largely quotes. Even if we take it for granted that the "death-rate of a place is proportional to its sunshine and inversely proportional to its latitude, other factors being eliminated," does it follow that the deathrate is dependent upon the amount of light, and have the other climatic conditions, and especially the parasitic insect life, no influence? Dr. Woodruff would have us believe so. He informs us that light is like alcohol, tea, coffee, and other stimulants. In moderation, it is beneficial; in excess, it is harmful. 'We can do without it, but our metabolism is too sluggish or defective if we do not get it." Excess of 66 |