摘要:

118 ELECTRICAL THEORY OF ADBORPTTON The writer considers the double layer as consisting of a swface of rigidly fixed atoms under continuous bombardment of positively and negatively charged ions, any particular point on the rigid surface becoming in turn negative, neutral and positive, these conditions arisdg in any order. The observed contact difference is the average effect of these conditions. Where several kinds of atoms are present in the solution the average number of any one of them at the surface will depend on their concentbration, valency and mobility. The variation of contact Werence from negative to neutral and positive was observed with cotton and aluminium sulphate near the neutral point. These variations occurred during the same experiment, the readings being direct measurements of E.1I.F.s developed by filtration under pressure.This point would be covered by putting n2 = 1 and = 2 or 3 in Mukherjee’s equation No. 13.118 ELECTRICAL THEORY OF ADBORPTTON The writer considers the double layer as consisting of a swface of rigidly fixed atoms under continuous bombardment of positively and negatively charged ions, any particular point on the rigid surface becoming in turn negative, neutral and positive, these conditions arisdg in any order. The observed contact difference is the average effect of these conditions. Where several kinds of atoms are present in the solution the average number of any one of them at the surface will depend on their concentbration, valency and mobility. The variation of contact Werence from negative to neutral and positive was observed with cotton and aluminium sulphate near the neutral point.These variations occurred during the same experiment, the readings being direct measurements of E.1I.F.s developed by filtration under pressure. This point would be covered by putting n2 = 1 and = 2 or 3 in Mukherjee’s equation No. 13.118 ELECTRICAL THEORY OF ADBORPTTON The writer considers the double layer as consisting of a swface of rigidly fixed atoms under continuous bombardment of positively and negatively charged ions, any particular point on the rigid surface becoming in turn negative, neutral and positive, these conditions arisdg in any order. The observed contact difference is the average effect of these conditions. Where several kinds of atoms are present in the solution the average number of any one of them at the surface will depend on their concentbration, valency and mobility.The variation of contact Werence from negative to neutral and positive was observed with cotton and aluminium sulphate near the neutral point. These variations occurred during the same experiment, the readings being direct measurements of E.1I.F.s developed by filtration under pressure. This point would be covered by putting n2 = 1 and = 2 or 3 in Mukherjee’s equation No. 13.118 ELECTRICAL THEORY OF ADBORPTTON The writer considers the double layer as consisting of a swface of rigidly fixed atoms under continuous bombardment of positively and negatively charged ions, any particular point on the rigid surface becoming in turn negative, neutral and positive, these conditions arisdg in any order.The observed contact difference is the average effect of these conditions. Where several kinds of atoms are present in the solution the average number of any one of them at the surface will depend on their concentbration, valency and mobility. The variation of contact Werence from negative to neutral and positive was observed with cotton and aluminium sulphate near the neutral point. These variations occurred during the same experiment, the readings being direct measurements of E.1I.F.s developed by filtration under pressure. This point would be covered by putting n2 = 1 and = 2 or 3 in Mukherjee’s equation No. 13.118 ELECTRICAL THEORY OF ADBORPTTON The writer considers the double layer as consisting of a swface of rigidly fixed atoms under continuous bombardment of positively and negatively charged ions, any particular point on the rigid surface becoming in turn negative, neutral and positive, these conditions arisdg in any order.The observed contact difference is the average effect of these conditions. Where several kinds of atoms are present in the solution the average number of any one of them at the surface will depend on their concentbration, valency and mobility. The variation of contact Werence from negative to neutral and positive was observed with cotton and aluminium sulphate near the neutral point. These variations occurred during the same experiment, the readings being direct measurements of E.1I.F.s developed by filtration under pressure.This point would be covered by putting n2 = 1 and = 2 or 3 in Mukherjee’s equation No. 13.118 ELECTRICAL THEORY OF ADBORPTTON The writer considers the double layer as consisting of a swface of rigidly fixed atoms under continuous bombardment of positively and negatively charged ions, any particular point on the rigid surface becoming in turn negative, neutral and positive, these conditions arisdg in any order. The observed contact difference is the average effect of these conditions. Where several kinds of atoms are present in the solution the average number of any one of them at the surface will depend on their concentbration, valency and mobility. The variation of contact Werence from negative to neutral and positive was observed with cotton and aluminium sulphate near the neutral point.These variations occurred during the same experiment, the readings being direct measurements of E.1I.F.s developed by filtration under pressure. This point would be covered by putting n2 = 1 and = 2 or 3 in Mukherjee’s equation No. 13.118 ELECTRICAL THEORY OF ADBORPTTON The writer considers the double layer as consisting of a swface of rigidly fixed atoms under continuous bombardment of positively and negatively charged ions, any particular point on the rigid surface becoming in turn negative, neutral and positive, these conditions arisdg in any order. The observed contact difference is the average effect of these conditions. Where several kinds of atoms are present in the solution the average number of any one of them at the surface will depend on their concentbration, valency and mobility.The variation of contact Werence from negative to neutral and positive was observed with cotton and aluminium sulphate near the neutral point. These variations occurred during the same experiment, the readings being direct measurements of E.1I.F.s developed by filtration under pressure. This point would be covered by putting n2 = 1 and = 2 or 3 in Mukherjee’s equation No. 13.118 ELECTRICAL THEORY OF ADBORPTTON The writer considers the double layer as consisting of a swface of rigidly fixed atoms under continuous bombardment of positively and negatively charged ions, any particular point on the rigid surface becoming in turn negative, neutral and positive, these conditions arisdg in any order.The observed contact difference is the average effect of these conditions. Where several kinds of atoms are present in the solution the average number of any one of them at the surface will depend on their concentbration, valency and mobility. The variation of contact Werence from negative to neutral and positive was observed with cotton and aluminium sulphate near the neutral point. These variations occurred during the same experiment, the readings being direct measurements of E.1I.F.s developed by filtration under pressure. This point would be covered by putting n2 = 1 and = 2 or 3 in Mukherjee’s equation No. 13.118 ELECTRICAL THEORY OF ADBORPTTON The writer considers the double layer as consisting of a swface of rigidly fixed atoms under continuous bombardment of positively and negatively charged ions, any particular point on the rigid surface becoming in turn negative, neutral and positive, these conditions arisdg in any order.The observed contact difference is the average effect of these conditions. Where several kinds of atoms are present in the solution the average number of any one of them at the surface will depend on their concentbration, valency and mobility. The variation of contact Werence from negative to neutral and positive was observed with cotton and aluminium sulphate near the neutral point. These variations occurred during the same experiment, the readings being direct measurements of E.1I.F.s developed by filtration under pressure. This point would be covered by putting n2 = 1 and = 2 or 3 in Mukherjee’s equation No.13.118 ELECTRICAL THEORY OF ADBORPTTON The writer considers the double layer as consisting of a swface of rigidly fixed atoms under continuous bombardment of positively and negatively charged ions, any particular point on the rigid surface becoming in turn negative, neutral and positive, these conditions arisdg in any order. The observed contact difference is the average effect of these conditions. Where several kinds of atoms are present in the solution the average number of any one of them at the surface will depend on their concentbration, valency and mobility. The variation of contact Werence from negative to neutral and positive was observed with cotton and aluminium sulphate near the neutral point. These variations occurred during the same experiment, the readings being direct measurements of E.1I.F.s developed by filtration under pressure.This point would be covered by putting n2 = 1 and = 2 or 3 in Mukherjee’s equation No. 13. REVIEWS OF BOOKS. The Structure of the Atom. By Professor E. N. DE C. ANDRADE, D.Sc., Ph.D. (London, 1923 : G. Bell & Sons, Ltd. Pp. 314. Price 16s.) On the one hand there exist several more or less popular accounts of the present position of atomic theory, while in more specialised books, such as those by Aston or Crowther, atomic structure is dealt with incidentally. On the other hand there is the English version of Sommerfeld’s great work. There, however, not only is the treatment too full for the average student of physics, but that book deals primarily with the Rutherford-Bohr atom and it is based almost entirely on spectroscopic evidence.Professor Andrade has dealt with his subject on broad lines and he approaches it from the chemical as well as from the physical side. The book is not always easy to read, for the reasoning is close and steps in the argument often omitted ; but it is intended for advanced students and not for beginners and such readers will find the book suggestive and highly stimulating. The statement of the rival dynamical and statical conceptions is fair and well- balanced, while occasional flashes of ironic humour will be found helpful to the formation of a balanced judgment in that borderland of scientific thought which lies between theory and speculation.The book is divided into two main parts dealing with the Nucleus and with Extranuclear Structure. It is well to be reminded that the modem nuclear atom rests on the sure foundation of Rutherford’s brilliant work on the scattering of a and B particles and was not primarily conceived to explain chemical action or spectra. Highly suggestive sections in Part I. are those containing some fascinat- ing speculations on the mechanism (p. 5 2 ) and the shape (p. 70). of the nucleus. Part I. proper ends with a general discussion of the evidence at present available bearing on the Structure of the Nucleus-admirably stated-and then follows an intermediate chapter (VIf I.) dealing with Optical Spectra, an extremely good summary of a subject exceptionally difficult of summarised treatment.This chapter is important in that it provides the evidence utilised in Part 11. in support of Bohr’s orbits, but a revision of this chapter will soon be called for, in view of much recent work on fine structure by Millikan and others. In his discussion of the Dynamic Model of the Atom, the author points out that the Bohr atom has been evolved by considering the characteristic radiations and the Langmuir-Lewis and other statical models have been elaborated from the chemical point of view. Nevertheless, he considers that the adhoc character of the statical model renders it far less acceptable than the dynamical atom, for the quantum theory, which is the essence of the Bohr scheme, was put forward quite independently of atomic theory, and it has proved its worth in many branches. of physics.It is true that the correspondence principle, by which Bohr has generalised his hypothesis, offers no physical explacation on the choice of orbits, yet on the whole it is justified by its results, in spite of numerous outstanding difficulties which are not shirked (pp. 174, 186, etc.). Indeed thereis no a #viuvi reason why we should ever arrive at a “mechanical” explanation of atomic structure. A refusal to be bound by logic, says the author in another place 402 This book fills a gap in English literature on sub-atomic physics.REVIEWS OF BOOKS 403 (p. 295), always characterises fruitful imaginative work. The book ends with an excellent chapter, highly condensed, on Magnetic Properties and Atomic Structure, in which the attempts-not yet altogether successful-to fit magnetic phenomena into the orbital atom are summarised.The author, while rejecting Whittaker’s magnetic atom model, considers that it foreshadows the possibility of a reconcilia- tion of the quantum theory and classical wave theory. In his concluding re- marks (Ch. XIV.) an ingenious way to a reconciliation between the dynamical and statical models is suggested. The references given at the end of each chapter will be found extremely useful in leading up to a detailed study of matters necessarily condensed in the text, while the concluding remarks, already referred to, indicate clearly which portion of our theory is-to use Platonic phraseology-definite ‘‘ knowledge ” and which is speculative ‘( opinion.” The book is altogether admirable, for it envisages the subject with a rare combination of breadth of outlook, sound judgment and stimuIating suggestiveness.A Dictionary of Applied Chemistry. Edited by SIR EDWARD THORPE, C.B., LL.D., F.R.S. Assisted by Eminent Contributors. Revised and Enlarged Edition. Volume V. Oxygen-Rye. (London, 1924 : Longmans, Green & Co. Pp. viii + 722. Price 60s. net.) The fifth volume of the new edition of this important work presents a vast amount of useful information. Among the larger contributions are several dealing with subjects which are either of very recent development or are but now receiving commercial application. Some of these are worthy of special mention, namely the articles on Radiology, Photosynthesis and Precipitation (electrical).The importance of refractories is, for the first time as far as the Dictionary is concerned, recognised by the inclusion of a short, though useful, article from the pen of Dr. Mellor. As was the case in the earlier volumes of the present edition, many of the articles have been copied from the former edition with but very slight alteration. The excellent article on Photography is a notable exception and has been carefully revised and greatly extended. A curious instance of lack of CO- ordination and careless revision is met with in the case of pyrogallol which is dealt with in two articles written by different contributors. The boiling point of the compound is given as 210’ in the article on Phenol and its homologues and as 292-294’ in the article (‘ Pyrogallol.” The latter is, of course, the correct value. Among other subjects which are dealt with at relatively great length may be mentioned Oxygen, Paints, Paraffin, Petroleum, Phosphorus, Platinum, Polarimetry, Potassium, Quinoline, Quinones, Resins and Rubber.The discrepancy was a feature of the previous edition also. H. M. S. Chemistry in the Twentieth Century. An Account of the Achievement and the Present State of Knowledge in Chemical Science. By Various Con- tributors and Edited by Dr. E. F. ARMSTRONG, F.R.S. (London, 1924: Ernest Benn., Ltd. Pp. 251. Price 15s.) The aim of this volume, as stated in the Preface, is to present, by means of a series of monographs, a statement of the present position of chemical science in Great Britain, as illustrated by the exhibits in the Chemical Hall at the recent British Empife Exhibition.It has been prepared under the guidance of a Com- mittee representing the Scientific Societies with Dr. Armstrong as Chairman and404 REVIEWS OF BOOKS Editor. The distinction of the authors of the separate chapters is sufficient indication of the high standard that has been aimed at and attained, but while most of the chapters are short accounts of specialised branches of chemical science and industry some three or four are of a more general character and the treatment is correspondingly on broader lines. It is, perhaps, invidious to point to particular articles where all is excellent, but special mention should be made of “The R61e of Chemistry in Physical Science” by Professor Irvine Masson, ‘‘ The Structure of the Atom ” by Professor E.W. de Costa Andrade, ‘‘ Crystallo- graphy” by Mr. T. V. Barker, “The Chemistry of Carbon Compounds” by Professor J. F. Thorpe, and ‘( The Chemistry of the Soil and of Crop Production ’’ by Mr. H. J. Page. Some of the slighter chapters are equally admirable and the Editor’s Introduction gives a vivid glimpse, which even the general reader will be able to appreciate, of the present state of cultivation of the great field of chemical science. The work is a worthy permanent record of the state of chemical achievement in 1924 portrayed in the Chemical Hall at Wembley. Spectroscopy. By E. C. C. BALY, F.R.S. In two volumes. Vol I. (London, As with many other works, the rapid march of events has caused a corre- sponding expansion of Professor Baly’s well-known treatise, which now appears in two volumes.It has more than once happened that such expansions have been attended with unfortunate results, a well-balanced book becoming a mere jungle of facts and theories, in which one with difficulty sees the wood for the trees. Professor Baly’s book has escaped this fate and, as far as a work of science can have permanent value, we may say of his treatise that, like the History of Thucydides, it should prove a K+LU i s &i-a possession for all time. The first volume, which now lies before us, exhibits a happy combination of mathematical and experimental knowledge. After a well-balanced historical introduction [but surely Grimaldi should not be credited with observations on interference .PI, the author proceeds to consider in detail the prism spectroscope, the ruled grating in theory and in practice, the resolving power of the spectroscope, and the infra-red and ultra-violet regions of the spectrum-all discussed with that wealth of experimental lore and disinterested enthusiasm for science which we have learned to associate with the name of Professor Baly.It is almost impossible to open the book at random without encountering some shrewd precept or piece of useful practical knowledge. Compare for example the hints given (p. 182) on cleaning a ruled grating by taking a collodion cast of it. But the work is much more than a collection of workshop or practical hints, and workers in the field of spectroscopy, conscious of the debt which they owe to the author, will anticipate with interest the appearance of his second and con- cluding volume.. 1924 : Longmans, Green & Co. Pp. 298. Price 14s.) A. F. Principles of Electroplating and Electroforming. By WILLIAM BLUM and GEORGE B. HOGABOOM. (New York and London, 1924: McGraw-Hi1 Publishing Co. Ltd., 6 and 8 Bouverie Street, E.C. 4. Pp. 356. Price 20s.) (London, 1923 : Oxford Technical Publications, Henry Frowde and Hodder & Stoughton, I Bedford Street, W.C. 2. Pp. 160. Price 16s.) These two books admirably supplement one another. The former is a complete text-book on the subject, covering a wider field than most and intended Modern Electroplating. By W. E. HUGHES, B.A., D.I.C.REVIEWS OF BOOKS 405 to assist men engaged in the industry to understand and apply the results secured in the various research and educational institutions. The authors are among the leading American authorities on electroplating, and they have been responsible for the important researches carried out at the Washington Bureau of Standards.The second book is of a somewhat different type. It is not a text-book, but a series of chapters on the deposition of metals of interest to engineers-silver and gold are excluded. The treatment is individual and the style conversational, and while the intention is to assist foremen platers, works chemists and engineers to meet their difficulties or to give them information, the help thus gven is not in the form of cut and dried categorical statements, but of a reasoned discussion of the principal problems arising in industrial work.Mr. Hughes, too, has been responsible for some noteworthy researches, and during the war he was chief research chemist to the Electrometallurgical Committee of the Ministry of Munitions. Consequently these two books between them give us the best knowledge and experience at present available in America and here, and this fact gives point to two or three general conclusions that emerge from their study. In the first place one is led to realise that the apparently simple processes utilised by the electroplater are really highly complex. This, no doubt, accounts for the paucity of our knowledge. Certainly much empirical information has been acquired, but little of it is true scientific knowledge, and we are still largely ignorant of what is really fundamental, namely the relation between the physical properties of an electrodeposit and the conditions under which it is produced- using the word “conditions” in its broadest sense.It is, therefore, not surpris- ing to meet on almost every page of both books a statement to the effect that ‘‘ much research is called for to clear up these difficulties ’’ or “ to fill these gaps in our knowledge.” More unfortunate than our ignorance is the small organised effort being made to dispel it. A certain amount of systematic research work is being carried out at the Northampton Institute in London and in Sheffield and Birmingham, but we have nothing here comparable with the school of Forster in Germany, or the Bureau of Standards at Washington. In innumerable directions possibilities exist for the improvement of existing processes (the silver plating process is practised substantially as it was 60 years ago), for the invention of new ones, and for the extended application to the arts of the electrodeposition of (‘ engineering ” metals such as iron, lead and tin, and the time has surely come for some organised effort to be made here to introduce science and the spirit of progress into the electroplating industries.Messrs. Blum and Hogaboom deprecate the short-sighted policy of the plater only studying such topics in chemistry and electricity which may be immediately applicable to electrodeposition. This is sound doctrine, but in spite of it nearly one quarter of the book is utilised in explaining the principles of chemistry, chemical analysis, electrochemistry and electricity.No student of electrochemistry will be ignorant of the elements of chemistry and physics, and platers without such fundamental knowledge should surely be encouraged to acquire it from independent sources. ‘‘ Ad hoc ” science has little value. The sage advice, born of much experience, given in the chapters on the character of the deposits and on the technique of plating and the equipment necessary wlll be found useful by practical platers, although, generally speaking, there does not appear to be much difference between American practice in these matters and our own. Of the chapters on the separate metals that on nickel is quite the best. The reasons given for the failure of cobalt plating to realise expectations (p.253) will be read with interest. Much detailed comment on these books will not be necessary.406 REVIEWS OF BOOKS One or two omissions may be noted. The excellent work of Field on the deposition of alloys is not referred to, and the chapter on this subject is somewhat slight. The short chapter on (‘ Experiments in Electrodeposition ” may stimulate some platers to make observations and records in a systematic manner, but real research workers will not be made in so easy a fashion. The book as a whole is decidedly good, but we must confess that the names of the authors led us to expect rather more originality in treatment and more information in substance. Mr. Hughes has been very successful in referring problems to first principles.He thus encourages the operator to think for himself and try and solve his own difficulties. We have found his book most stimulating and suggestive. He has not attempted to exhaust his subject, but he is at his best when discussing the structure of electrodeposits and their physical properties. These parts of the book are enriched by numerous fine photomicrographs. In an otherwise excellent chapter on copper, something might have been said about the mechanial properties of thick deposited plates, such as are used by the printer-engraver. The combined toughness and ductibility here required-as indeed in other instances and other metals-is by no means easy of attainment and writers usually ignore the problem. In the section on so-called “ steel-facing ” the ferrous-ammonium chloride solution is not referred to, although this is a favourite one in English practice.Useful features worthy of mention are the Tables of Defects given in the cases of several metals and the references at the end of each chapter. F. S. S. A Treatise on Electrometallurgy. By WALTER G. MCMILLAN. Revised by W. R. COOPER, M.A., B.Sc. Fourth edition. (London, 1923 : Chas. Griffin & Co., Ltd. Pp. xv + 449. Price 21s.) In preparing a new and revised edition of this well-known book on Electro- metallurgy, which has been out of print for about four years, Mr. Cooper has carried out the revision so as to keep the plan of the work on the lines conceived by the original author. The book is intended as a textbook for the whole range of electrometallurgy, by which term the authors denote the application of electrical methods to the separation or the solution of metals from substances containing them and also the treatment of metals for specific purposes in the arts.The greater part of the book, however, deals with the electro-deposition of metals and this part contains much valuable information. In other directions, the accounts are much briefer, the use of the electric furnace for the melting of metals, for example, being dealt with in the merest outline. As a whole, the revision appears to have been well carried out, though in some respects more information might have been given, e g . with regard to the deposition of chromium, and the book will without doubt continue to enjoy the reputation it already has as a textbook on electrometallurgy.Theoretical Metallurgy. By REGINALD S. DEAN. (London, 1924 : Chapman & Hall, Ltd. ; New York: John Wiley & Sons. Pp. viii + 246. Price This volume really takes the place of a second edition of the author’s translation of Dr. Schenck’s (( Physical Chemistry of the Metals.” The original German book appeared in 1909 and the English translation in 1919, and apparently the original German text was not revised to any great extent before 15s.)REVIEWS OF BOOKS 407 the English translation was made. Hence, as would be expected, very drastic revision of the existing text, in addition to the incorporation of a great deal of new matter, was found to be necessary in preparing a new edition. I n the review in these Transactions of the earlier edition, the opinion was expressed that the book was a convenient summary of the application of physical chemistry to the problems of metallurgy.This applies to the new volume and speaking generally its greatest value consists in indicating to metallurgical students the great help which may be obtained by such application. It has also a considerable sphere of usefulness from the opposite standpoint of making easily available to the physical chemist a mass of information obtained by the scientific metallurgist which is of great interest to the former but liable to be overlooked by him since it is scattered through metallurgical literature. Unfortunately, however, the book is open to rather serious criticism. As in the earlier edition there are quite a number of inaccuracies in the data given while some of the text is misleading.This applies particularly to the sections dealing with iron and its alloys. In addition to this the treatment is in general too brief; in many parts the text would have been much improved and made of greater value to the student had considerably more detail been given. It is a pity that the text is marred in this way, as the idea of emphasising the use of physico-chemical methods for metallurgical problems (and incidentally the value of metallurgical material for the needs of the physical chemist) is excellent, while the general arrangement of the book has been well thought out. I t is to be hoped that in any future edition the shortcomings noted above will be rectified. J. H. G . M. Practical Microscopical Metallography.By R. H. GREAVES, D.Sc. and HAROLD WRIGHTON, B.Met. (London, 1924: Chapman & Hall, Ltd. Pp. x + 125. As its title implies, this book deals with that part of metallographp which is concerned with the structure of metals as revealed by the use of the microscope. The metals dealt with comprise iron, steel (both ordinary carbon steels and alloy steels) and some of the more commonly used non-ferrous alloys, and in each case the structural changes produced by varying conditions of treatment are briefly but clearly described, the text being illustrated by a large number of photo- micrographs which, besides being well chosen for this purpose, are themselves remarkably good specimens of the art of photomicrography. For some rather obscure reason the authors regard macroscopic examination as outside the scope of the book and hence this essential preliminary to microscopic work is very scantily treated.As a whole, however, the contents of the book are good, though criticism could be given on a few minor points, and there is no doubt that it will prove very useful not only to students of metallography, whom the authors prob- ably had primarily in mind when writing it, but also to engineers and others employed technically in works who wish to gain some insight into the changes produced during the working and treatment of metals, but find the larger text- books on metallography too complex for their liking. Price 16s.) J. H. G. M. The Corrosion of Metals. By ULICK R. EVANS, M.A. (London, 1924: Edward Arnold & Co.Pp. xi. + 212. Price 14s.). The practical importance of the corrosion of metals is so obvious to those The problem, however, is one who have to use them as to require no emphasis.REVIEWS OF BOOKS of great complexity and although a vast amount of investigation has been carried out, the knowledge of the mechanism of the initiation and progress of metallic corrosion is far from being complete. Probably owing to the fact that most ferrous alloys are more susceptible to corrosion than other alloys used in engineeering work, more attention has been devoted to their behaviour to various corroding media than to the other alloys and there has been a tendency to develop theories regarding the corrosion of iron and steel which depend on attributes of iron not possessed by other metals and which therefore will not apply to these.Such theories may eventually prove to be necessary but, as they obviously complicate the subject of corrosion, it would be preferable if the theory of corrosion could be developed on a basis which would include all metals unless such a standpoint is proved to be untenable. Mr. Evans is one of those who believe that corrosion is electrochemical in character and that the principles governing it apply to metals generally, and in his book, recently published, he has set out his views in a very able manner. In a book of about 200 pages it is not possible to deal in detail with all phases of corrosion but in endeavouring to get down to basic principles, Mr. Evans has undoubtedly taken a step in the right direction of evolving order out of the con- fusion which at present exists.One of the difficulties with regard to the corrosion of most metals has been the fact that rapid attack is very liable to take place at those points, e.g. the bottom of the pits, or under dirt and dtbris, where oxygen has least direct access. By his conclusive proof that differences of oxygen concentration in the corroding fluid may set up concentration cells, and that in such cells the part of the metal bathed by the fluid with lower oxygen content functions as the anode, the author has supplied a really convincing explanation of why the localised corrosion mentioned above takes place. The book is well written and there can be no doubt that it will be exceedingly useful both to the metallurgist and the engineer, and will provide them with much food for thought.It equally marks a definite step forward in the solution of the problem of corrosion. Cadmium : Its Metallurgy, Properties and Uses. By NORMAN F. BUDGEN, Ph.D., M.Sc. ; with Foreword by Professor T. TURNER, M.Sc., A.R.S.M., F.I.C. (London, 1924 : Charles Griffin & Co., Ltd. Pp. 239, eleven plates, and 57 figures in text. Price 21s.) Twenty years ago, the world’s supply of cadmium came from the zinc- smelting district of Upper Silesia. Since 1906, an important cadmium industry has sprung up in the United States, the main sources of supply being the dust from the bag-houses of lead and copper-works ; only those ores of lead and copper which contain zinc minerals yield a cadmiferous dust.Cadmium is now manufactured also in Tasmania, and smaller amounts are produced else- where. The growth of the cadmium industry may be attributed in part to the fact that the zinc sulphate solution used in the electrolytic production of zinc, as well as that employed in the manufacture of white lithopone, must, of necessity, be freed from cadmium. Although descriptions of these new industrial processes have occasionally appeared in technical journals, it has remained to Dr. Rudgen to write what Professor Turner describes as the ‘‘ first comprehensive treatise ” on the subject. This difficult task-which must have involved a far greater expenditure of labour and thought than would be required for a new book on an ‘‘ established ” metal,REVIEWS OF BOOKS 409 such as copper or lead-has been accomplished with great success, and all who are concerned with cadmium or its compounds will be grateful to Dr.Budgen for the appearance of this work. The early chapters dealing with the metallurgy of cadmium are excellently written. In view of the manner in which the extraction of cadmium is interwoven with the technology of other metals, it can have been no easy task to deal with the subject clearly. The author has prepared, however, a large number of diagrams on the pattern of works “flow-sheets” which show at a glance the sequence of the operations, and the disposal of the different products ; these diagrams are a great help in reading the text. In the next edition of the work, the subject might be made even clearer by a more systematic use of the various kinds of type available for the heading of sections and sub-sections.A useful chapter follows giving statistical tables of the production of the metal ; the statistics available in most cases include the year 1922, and in some cases 1923 also. Next come three chapters devoted respectively to the Physical Properties, Chemical Properties and Analysis of the metal ; these contain a vast quantity of information, and are provided with some hundreds of references to journals where still fuller details can be obtained. In discussing the question of Allotropy, however, the author has-no doubt, unintentionally-given only one side of the case. The views of Cohen and Helderman, founded on changes of density observed when turnings of cadmium or other soft metals are heated with a salt solution, are accepted without reserve ; the variability of the so-called ‘‘ transformation temperature,” as found in different samples, is explained on the comfortable assumption that there are probably “more than two modi- fications ” present.But, as Rosenhain-although himseif a supporter of the view that more than one allotropic modification exists in cadmium-has pointed out, Cohen and Helderman’s method is open to grave objections, since they used cold-worked material ; the density-changes observed might have been due to causes other than allotropy. Moreover, in the analogous case of copper, Burgess and Kellberg, as a result of careful work, have been unable to confirm the allotropic change postulated by Cohen and Helderman.Dr. Budgen reproduces practically the whole of Greenwood’s paper on the effect of cold-work on cadmium, in which the notion of several allotropes is supported ; the two researches on recrystallisation and grain-growth in worked and unworked cadmium carried out by M. Cook, who interprets his results without recourse to allotropy, receive no mention. There are two useful chapters devoted to the alloys of cadmium, binary, ternary and quarternary. No less than 22 constitutional diagrams of alloy- systems containing cadmium are reproduced in full, besides other diagrams correlating physical properties with composition ; there are also some excellent photographic reproductions of micro-sections and fractures. One notes with interest the references to Dr. Budgen’s own researches on the copper-cadmium and lead-cadmium alloys and on the aluminium-zinc-cadmium system.After a chapter on the electrodeposition of the metal, the book finishes with an interesting chapter on the uses of cadmium. Much space is rightly devoted to the employment of the metal as an addition to copper ; the cadmium increases the strength and resistance to abrasion without greatly diminishing the electrical conductivity ; several engineer’s reports of the good wearing properties of the copper-cadmium copper wire employed in electric traction are incorporated. The use of cadmium in the new tarnish-resisting silver only receives brief mention, but the employment of the metal as a deoxidiser for410 REVIEWS OF BOOKS silver is treated at some length in the chapter on alloys.Among the compounds of cadmium, reference is made to the use of the sulphide as a pigment, whilst attention is drawn to the possibility of employing cadmium lithopone for the same purpose ; mixtures of this body with ordinary zinc lithopone are stated to give a pleasing cream-yellow when rubbed out with oil. U. R. E. Analytical Mechanics. By E. H. BARTON, F.R.S. Second Edition, revised and enlarged. (London, 1924 : Longmans free No. Pp. 593. Price zrs.) Good wine needs no bush, and Professor Barton’s Analytical Mechanics now appearing in a second edition demands no detailed notice. The standard is avowedly that of the final degree of the University of London, but the student who has assimilated the contents and has worked intelligently a selection from the 1x00 examples scattered through the book will possess a knowledge of the fundamentals of Applied Mathematics considerably ahead of that of the average degree candidate.The section on Kinetics traverses the beaten path, and culminates in a sound (and thoroughly physical) discussion of the motion of a top. The section on Statics deals, inter atia, with Attractions, Potential, Machines, Graphical Statics, Virtual Work, and the Theory of Wrenches. Sections on Hydrostatics and Hydrokinetics, and a brief chapter on Elasticity which might well have been expanded to contain some account of simple cases of spherical and cylindrical strains, close the volume. Throughout the whole work the requirements of the student of physics have been borne in mind.The discussions of mechanical principles are refreshingly alive, and are illustrated by the action of actual machines (as opposed to the idealised levers and screws of the Todhunter school). We hope that this aspect of the book will be further emphasised in the next edition and that, to take an example at random, room will be found for a discussion of such work as that by Conrady on the precision balance. A. F. Relativity. A Systematic Treatment of Einstein’s Theory. By J. RICE, M.A. In spite of the almost alarming dimensions attained by the literature of relativity, there is a decided place for this book. Previous works have been ad- dressed either to the general reader, with or without an elementary knowledge of physics, or to the mathematical physicist.This is a student’s text-book, intended to take its place in a normal cqurse of physics and mathematics and designed for the average undergraduate reading for an honours degree. None can dispute the need for such a work, for the basic ideas of relativity, whether or not one accepts Einstein’s formulation of them, must inevitably form part of the founda- tions of the physics of the future, and the sooner the student becomes acquainted with them the better. The author has adopted the method of building up the theory step by step-almost historically-and the mathematical equipment expected is such as should be possessed by the class of student he addresses. More advanced mathematical conceptions, such as tensor analysis or the Riemann analysis, are introduced as required and an intelligent student should find no great difficulty in following them. The method may be slow and some- times even laboured, but in the end we think the present-day student, schooled as he has been in Newtonian conceptions, will ‘‘ arrive ” with more certainty than (London, I923 : Longmans, Green & Co. Pp. 397. Price 18s.)REVIEWS OF BOOKS 411 if a more deductive method had been adopted. is the summary of each chapter given in the table of contents. A useful feature of the book Birkbeck College Centenary Lectures. (London, 1924 : University of London Press. Pp. 178. Price 5s.) The Birkbeck College, now a constituent of London University, was founded in 1823 as the London Mechanics’ Institute, and last year the centenary of its foundation was celebrated by the delivery of a series of memorial orations, in which were recorded the progress made in the principal branches of knowledge during the lifetime of the College. It was a happy idea to publish these addresses for they are well worth preserving in permanent form. The subjects dealt with were Philosophy (Lord Haldane), Economics (Sir William Ashley), Education (Sir Michael Sadler), Physical Science (Sir Joseph Thomson), Biology (Mr. W. Bateson) and Historical Studies (Dr. G. P. Gootch). The late Prime Minister, who speaks of the debt he owes the College, contributes in the form of a Preface a fitting eulogy of what the Birkbeck has done for higher education in London, and the epilogue to the volume is the Centenary Foundation Oration delivered by the present Prime Minister. The book is besutifully printed and produced by the University of London Press.

ISSN:0014-7672    

DOI:10.1039/TF9242000402

出版商:RSC    

年代:1924

数据来源: RSC

摘要:

118 ELECTRICAL THEORY OF ADBORPTTON The writer considers the double layer as consisting of a swface of rigidly fixed atoms under continuous bombardment of positively and negatively charged ions, any particular point on the rigid surface becoming in turn negative, neutral and positive, these conditions arisdg in any order. The observed contact difference is the average effect of these conditions. Where several kinds of atoms are present in the solution the average number of any one of them at the surface will depend on their concentbration, valency and mobility. The variation of contact Werence from negative to neutral and positive was observed with cotton and aluminium sulphate near the neutral point. These variations occurred during the same experiment, the readings being direct measurements of E.1I.F.s developed by filtration under pressure.This point would be covered by putting n2 = 1 and = 2 or 3 in Mukherjee’s equation No. 13.118 ELECTRICAL THEORY OF ADBORPTTON The writer considers the double layer as consisting of a swface of rigidly fixed atoms under continuous bombardment of positively and negatively charged ions, any particular point on the rigid surface becoming in turn negative, neutral and positive, these conditions arisdg in any order. The observed contact difference is the average effect of these conditions. Where several kinds of atoms are present in the solution the average number of any one of them at the surface will depend on their concentbration, valency and mobility. The variation of contact Werence from negative to neutral and positive was observed with cotton and aluminium sulphate near the neutral point.These variations occurred during the same experiment, the readings being direct measurements of E.1I.F.s developed by filtration under pressure. This point would be covered by putting n2 = 1 and = 2 or 3 in Mukherjee’s equation No. 13. REVIEWS OF BOOKS BOOKS RECEIVED. Colloid Symposium Monograph. Papers and Discussions presented at the First National Symposium on Colloid Chemistry. University of Wisconsin, June, 1923. Edited by J. Howard Mathews. (Published by the Depart- ment of Chemistry, University of Wisconsin, Madison, U.S.A. Pp 419. Price 18s. To be obtained from Messrs. H. K. Lewis & Co., Ltd., 136 Cower St., W.C. I . ) Shirley Institute Memoirs.(Published by the British Cotton Industry Research Association, Shirley Institute, Didsbury, Manchester. Pp. 394 with index.) An oration by ALEXANDER RUSSELL, M.A., D.Sc., F.R.S., delivered in the University of Glasgow at the Commemoration on 25th June, 1924, of the Centenary of Lord Kelvin’s birth. (Glasgow, 1924 : MacLehose, Jackson & Co. Pp. 22.) Vol. 11. 1923. William Thomson, Lord Kelvin, 1824=1907. Lord Kelvin as Professor in the Old College at Glasgow. BY DAVID MURRAY, M.A., LL.D. (Glasgow, 1924 : MacLehose, Jackson & Co. Pp. 22.) The National Physical Laboratory. Report for the year 1923. (London, 1924. H.M. Stationery Office. Pp. 225. Price 13s. 6d.) Report of the Committee of Privy Council for Scientific and Industrial Research for the Year 192344.(London, 1924. H.M. Stationery Office. Pp. 139. Price 3s.) Joint Committee for the Standardisation of Scientific Glassware. Report No. I. on Units of Volume. Members of the Faraday Society may obtain copies of this pamphlet at price 6d., post free, on application to Mr. G. S. W. Macleod at the Institute of Chemistry, 30 Russell Square, W.C. I.412 REVIEWS OF BOOKS The Power Resources of the Commonwealth of Australia and the Mandated Territory of New Guinea. A report to the World Power Conference, London, 1924. Compiled by the Institution of Engineers, 5 Elizabeth Street, Sydney, Australia. (Sydney, 1924. Pp. 131, with numerous maps, charts and illustrations. N.p.) Variations of Apparent Bearings of Radio Transmitting Stations. Part I. Observations on Fixed Stations.February 192 i-Marcb 1922. By R. L. ROSE-SMITH, Ph.D., M.Sc., D.I.C., A.R.C.Sc. (London, 1924. H.M. Stationery Office. Pp. 96, with charts and diagrams. Price 3s. 6d.) This pamphlet forms Special Report No. 2 of the Radio Research Board of the De- Experiments by EZRA GRIFFITHS, D.Sc (London, 1924 : H.M. Stationery Office. Pp. 55. Price 2s.) This is a revised edition of Special Report No. 5 by the Engineering Committee of the Food Investigation Board set up by the Department of Scientific and Industrial Research. The apparatus devised for the measurement of thermal conductivity of heat- insulating materials is described, as well as the results of tests made on various materials used or appropriate for use in cold storage. Abridged Scientific Publications from the Research Laboratory of the Eastman Kodak Company. Vol. VII., 1923. (Rochester N.Y., 1924 : Eastman Kodak Company. Pp. 139. N.p.) partment of Scientific and Industrial Research. First Report on Heat Insulators. Official Report of the Empire Textile Conference, 1934. (Manchester, Re- 1924 : The Textile Institute, St. Mary’s Parsonage. duced price 5s. to Members of the Faraday Society.) The greater part of this Report consists of Papers presented to the Conference held at Wembley last June dealing with the economic aspects of the textile industry, processes of manufacture and the research work of the principal Research Associations connected with the Industry. It also includes the Report of the General Discussion on ‘‘ Physical and Physico-Chemical Problems relating to Textile Fibres ” reprinted from pp. 223-322 of the present issue of Transactions. Pp. 267 + 100. ABERDEBN : THE UNIVERSITY PRESS

ISSN:0014-7672    

DOI:10.1039/TF9242000411

出版商:RSC    

年代:1924

数据来源: RSC