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NEW BOOKS Trait6 de Physique. B y 0. D . Chwolson. Ouvrage traduit sur les Editions russe et allemande par E. Davaux. Edition revue et considdrablement augmentbe par l’Auteur, suivie de Notes sur la Physique thdorique par E . Cosserat et F . Cosserat. Tome troisikmr, second fascicule. 16 X 25 cm; p p . vii 336. Paris: A. Hermann, 1910. Price: paper, 11 francs.-This section of the third volume contains general thermodynamics, fusion and vaporization. On p. 476 we find an interesting discussion of the theorem of LeChatelier. “As introduction to our further studies we will take up the theorem of LeChatelier-Braun. It tells us less that1 the second law of thermodynamics because i t gives no information as to the quantitative laws governing physical phenomena; but what it has in common with the second law is very interesting. It indicates the direction in which a physical change will go under given conditions. One might think that the theorem of LeChatelier-Braun would be of no importance in comparison with the second law of thermodynamics which tells us so much more, but this is not the case. The application of the second law to physical phenomena calls for adva.nced knowledge in making the analysis and for great care in drawing the conclusions. The conclusions are also in a mathematical form and may not be readily applicable. On the other hand the theorem of LeChatelier-Braun appears as a simple rule, which is easily remembered and which therefore may render great service. ’It enables us to keep clear the regular but complex sequence of phenomena, to straighten out difficult cases, and even t o predict new facts. The theorem ought to be much more widely known than it is and it ought to be introduced into the elementary teaching instead of the second law of thermodynamics because this latter cannot be made easily applicable.” On p. 502 the author apparently takes quite seriously Ostwald’s formulation that “of all the possible transformations of energy, that one will take place which causes the greatest change in a given time.” It is not possible for this to be true and a t the same time to accept Ostwald’s so-called law of the primary formation of the instable phase. The phenomena of liquefaction and evaporation are treated, as they should be, from the phase rule point of view. The author accepts Tammann’s view that amorphous substances are supercooled liquids but he falls into the usual error, p. 616, that superheating of a solid is practically unknown. It is quite easy to superheat acetaldoxime 30’ and the phenomenon is a general one in all cases IV. D. 8 . where a second modification is formed slowly in the melt.

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Trait6 de Physique, B y 0. D. Chwolson. Ouvrage traduit sur les &ditiorzs russe et allemande fiar E . Davaux. gditions revue et considdrablement augmentde par I’Auteur, suizie de Notes sur la Physique thkorique par E . Cosserat et F . Cos430. P a r k : serat. Tome quatrikme, premier jascicule. 16 X 25 cm; p p . vii A . Hermann, 1910. Price: paper, 12 francs.-This section deals with the phenomena connected with a constant electric field. I n the introduction, p. 3, there is an interesting account of the present state of our knowledge. “ I n order to form a truly scientific judgment on any part of physics, it is

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New Books necessary to have a cleav uizderstatiding of the significance a t that moment of a given theory or given hypothesis. Let us suppose that there is a conflict between different hypotheses or theories, that people defend each obstinately as applied to some part of the subject, and that i t is necessary to substitute the reascnings, deductions and conclusions of one of these hypotheses or theories for those of another when passing from one part of the subject to another. In such a state of things, anybody, who thought that the struggle might end, t h a t one of the theories might prevail, and that i t was possible to present all parts of the subject from a single point of view, would be considered as not having a clear understanding of that branch of science. “This is exactly the state of things with regard to the electrical and magnetic phenomena. Without exaggeration we may say that, in the part of this science which deals with the explanation of the phenomena, there is no solidly established theory on which one can rely with absolute safety and which will take account of all the phenomena.” The author distinguishes the electrostatic phenomena, the magnetic phenomena, the phenomena connected with the electric current, the phenomena of electrical radiations, the phenomena of the electrical discharge and the phenomena of radioactivity. He points out that there is no single theory which takes account satisfactorily of all these phenomena. On p. 205 the author discusses the problem of the voltaic cell. In a cell of the Daniel1 type he calls e4 the potential difference between the metals: c3 and e,, are the differences of potential between zinc and zinc sulphate, copper and copper sulphate respectively ; while P~ is the potential difference between the two solutions and the sum of the four is E, the electromotive force of the cell. “Where are we to look for the source of the difference of potential which we observe in a cell on open circuit? Is it where the metals are in contact, where the electrolytes are in contact with the metals, or in both sets of places? Many authors of high standing believe that e, is very small in comparison with e, and e3 and that it does not exceed a few thousandths of the value of E. Consequently the contacts between the metals and the electrolytes are the chief sources of the electromotive force of a cell and are the only ones that need ordinarily be considered. This is the view held by the German school of electrochemists: Ostwald, Nernst, Jahn, LeBlanc, Liipke and others. There are other scientific men, especially in England (Lodge for instance) who believe that e, = o and that the contact between two metals gives rise to no electromotive force. [This is scarcely a fair statement of Lodge’s view.] At the same time we see physicists, no less distinguished, measuring the values of ed for different pairs of metals and finding that e4 may be half, three-quarters or even a larger fraction of E, so that e4 may run up almost to a volt. We find innumerable experiments and measurements by both sets of partisans and also criticisms of the experiments, which appear sometimes to have nothing to do with the subject and almost to demonstrate ignorance on the part of the objectors as to what they are trying to prove. It is not for us to take sides with either party nor to adopt one opinion on the other as to the value of e,. Our business is simply to present a sketch of the actual state of the science and to show what has been done by both sides. Although the fundamental problem bas not yet been solved, that will not interfere with a presentation of the facts because the

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really important thing is the value of E, the sum of the disputed single potential differences, and there is no disagreement as to the value of E.” The last chapter is devoted to atmospheric electricity. Of general interest is a paragraph on p. 423. “Brillouin (1900) found that when ice is electrified negatively it loses its charge rapidly under the influence of ultraviolet radiations and that this does not take place when we have water instead of ice. From this he deduced the following theory. If there is an electric field in the atmosphere at any moment, the needles of ice in the cirrus clouds are electrified positively a t one end and negatively at the other. If the negatively charged ends of the ice needles are exposed t o solar ultraviolet radiations, the needles thus illuminated lose all their negative charge and become electrified positively. Brillouin assumes that the negative electricity lost by the needles of ice is taken up by the surrounding air. When the needles separate from the surrounding air, the ivhole of the cloud appears positive. When cirrus clouds are formed by mixing, there are frequent independent movements of neighboring masses of air, some of which are cloudy and some of which are clear. The negatively charged air separates from the positively charged cirrus. If the mass of negatively charged air descends until it reaches the ground, the innumerable leaves and blades of grass facilitate the transfer of electricity from the air t o the soil. The ground becomes charged negatively with respect t o the air. At the surface of the ocean it is quite different. The air remains negative and becomes saturated with water vapor. When this vapor, on expansion, condenses to fine drops, these latter act like fine points and take the charge from the air. The cumulus clouds near the ocean are therefore negative. At the surface of the earth no direct action of ultraviolet radiations can be detected because almost no such radiations get thus far and because water is not sensitive to them. Wilder D. Bancroft Trait6 de Chimi6 g6n6rale. B y IF. Nernst. Translated from the sixth German edition by -4. Corvisy. Part I . 17 X 2 j cm; j I o p p . Paris: A . Hermanu et Fils, I ~ I I . Price: paper, 12 francs.-This French edition is translated from the sixth German edition, ivhich is very different from the earlier ones. This first volume only includes the general properties of substances and the special facts connected with atoms and molecules. The headings of the chapters are : introduction; gases; liquids; solids; physical mixtures; dilute solutions; atomic theory; kinetic theory of molecules; determination of molecular weights; constitution of molecules; physical properties and molecular structure; dissociation of gases; electrolytic dissociation; physical properties of salt solutions; atomic theory of electricity; metals; radioactivity; colloids; absolute size of the molecules. Nernst defines a crystal, p. 84, as a homogeneous substance in which the physical properties vary in different directions from any point inside the crystal. In this definition no mention is made of the geometrical form of the limiting surface because this form is only the outward sign of the crystalline state. The definition thus includes the liquid crystals and excludes amorphous substances, which is as it should be. Stress is laid, p. 309, on the fact that the molecular weight of the liquid solvent does not appear in the van’t Hoff-Raoult formula. On the other hand,

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i t is rather implied, p. 137, that melted isomorphous mixtures may coexist over the whole range with crystals of identically the same composition as the melt. This is theoretically impossible and it has been shown that Kuster’s assumption to the contrary was due to the lack of sufficient accuracy in the experiments. The paragraph on dualistic and monistic theories, p. 323, is very good and so is the next one on variable valence. The chapter on colloids is not up to what it should be. Nernst believes that vapor pressure measurements, pp. 480-483, enable us t o determine the true molecular weights of colloids; the treatment of peptonization and pectization is absurdly inadequate ; and the whole chapter has been written in a purely perfunctory way. The translator has done his work well biit he has not furnished a name index or a subject index. It may be that these will appear in the second part. Ii‘ildo. D. Baiicroft Electro-Analysis. B y Edgar F . Snrith. Fifth edition. 19 X 15 cin; p p . Philadelphia: P. Blakiston’s Soli & Co., 1911. Pi.icc: $2.50 viet.-In the preface the author says: “The greater portion of the new material, presented in the pages which follow, refers to the rapid precipitation and separation of metals, the use of a mercury cathode with rotating anode and the employment of a new cell in the determination of cations and anions. To give this material the space it so abundantly deserves suggested the elimination of the minute directions found in the various electrolytes used with stationary electrodes, but it developed that beginners in electro-analysis learn much from the execution of details, the handling of deposits and other points which arise constantly in work of this character. Further there will always be persons who, from preference or from the lack of facilities to carry out the newer methods, will make determinations and separations with stationary electrodes. Indeed, these earlier methods constitute a fundamental step in the development of analysis through the agency of the current, and are therefore retained in their original forms except where experience has recommended alterations. So long as the time factor continues to be of no moment the older procedures will appeal to the analyst. “ I t may be stated that the rapid methods of analysis set forth in detail in this text, including those in which the mercury cathode plays an important r61e, have been subjected to rigorous tests in this laboratory and have invariably brought success to all working with ordinary care. “The section describing the determination of cations and anions cannot fail to excite interest and inquiry. That the estimation, for example, of barium and chlorine, in barium chloride, may be made in an hour or less, while hours would be required by the time-honored methods, will naturally lead one t o pause. The neatness and accuracy of such determinations also recommend them. The determination of the ferro- and ferri-cyanogen and other anions indicates still greater possibilities in the application of the current to analysis. “The very latest proposals regarding the value of graded potential in separations and the possibility of effecting organic combustions by means of the electric current receive ample consideration. The paragraphs on theoretical considerations will throw much light upon the deportment of metals in solution and assist in explaining many heretofore obscure reactions.” 328

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Some people may take issue with the last paragraph quoted; but that has no real bearing on the merits of the book. Mr. Smith is recognized as the leading authority in the world on the practice of electrolytic analysis. We also owe t o him more new and varied methods of analysis than to any other man. The only criticism that the reviewer has ever heard in regard to the previous editions is that i t has sometimes been difficult to duplicate results obtained with great ease in the Pennsylvania laboratory. The test of a set bf directions is not that they shall work well in the laboratory of the inventor of the methods; but that they shall be proof against the marvelous ingenuity of the students in making mistakes when there is no possible justification for so doing. The reviewer hopes that the new edition will stand even this test. W'ilder D. Bancrojt Die Theorie des Farbeprozesses. B J , L. Pelet-Jolivet. 16 X 25 cm; 224 Dresden: Theodor Steiitkopff, I ~ I I . Price: paper, 7 marks; bound, 8 marks._ The subject is discussed under the following heads: general properties of dyes; adsorption; contact electrification; relations between adsorption and contact electrification; different observations on contact electrification and dyeing; relative permanency and fastness of dyes; the nature of the combinations formed during dyeing. There is a great deal that is interesting in the book. Under general properties the author discusses: classification of dyes; solubility of dyes; composition and nature of basic dyes; electrical conductivity of dyes; conductivity of dyes for cotton; relations between solutions of dyes and colloidal solutions; mutual action of basic and acid dyes; quantitative determination of dyes. Under contact electrification we find, among other sections, one on the effect of salts on dyeing, one on fixing different derivations of the same dye, and one on the mechanism of fixing basic and acid dyes on the fibers. In the fourth chapter thc author discusses the adsorption of dyes in presence of electrolytes and also the capillary rise of dyes. The chapter on the fastness of dyes is a bit disappointing because one does not get anywhere. In the last chapter the author expresses the conviction that, in the majority of cases, adsorption is the most important factor in causing the fixing of the dye on the fibers. The author has given a great number of facts and the book will prove of great value. It has just one serious defect. The author has been so much interested in details that he has nowhere given any presentation of the theory of dyeing. If he would add a final chapter in which he told what we now know about dyeing, it would double the usefulness of the book. I Vilder D . Bancroft

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Die Anlauffarben: eiize iieue Methode ziir C'iitersuchung opaker Erze a n d Erzgcniengt.. l j y M a x Leo. 16 X 25 cm; 7 2 p p . Dresdeii: Theodor Steinkopfl, I ~ I I . Price: 2 marks.-Owing to the difficulty in polishing ore surfaces, the author claims that one cannot use the methods of etching which prevail in metallography. This would seem to be largely a question of knowing how to polish a rock surface. Unless one knows how, it is not easy to polish and etch an alloy containing two soft metals. However that may be, the author has developed a method of coloring different portions of a rock surface by heating, by treating with chemicals, by making the one sample anode or cathode. In

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the last case metallic copper is often precipitated on the surface. The method has been tested for sulphide ores and apparently works very well. While the method seems to be a good one, the presentation is extremely bad, the author stating his facts in so confused i~ way that it is very difficult to make out exactly what he has done. Wilder D . Bancrofl

A Laboratory Manual of Inorganic Chemistry. B y Eugene C. B.inghnni and George F . IVhite. 14 x ZI cm; v 146 P P . New I‘ork: John Il.ilcI, and Sons, 1911. Price: $I.oo.-In the preface the author says: “The first year’s work in chemistry is inevitably concerned with a large number of chemical facts among which the properties of acid radicals and metallic radicals play a prominent rale. The interest and reality of these facts must ever be in direct proportion to the intimacy of the student’s contact with them. Information from text-books, or even the best lecture demonstrations cannot compete with laboratory experimentation in making the facts real. It seems to the authors, therefore, that a course in inorganic preparations and systematic qualitative analysis, with a few carefully chosen quantitative experiments afford the best background for the theoretical development of the science. “In the study of a rapidly expanding subject, like Chemistry, there is danger of superficiality. Writers are tempted t o cover the whole field with many short experiments. The result may be that the teacher comes t o feel that the student is not grasping the fundamental facts in the multiplicity of experiments, and he may allow the student to yield to the temptation to hurry. Hence the number of experiments has been cut down to a minimum, necessary for the understanding of the s,ubject in its elementary phases. On these experiments the student may confidently linger until they become a part of himself. Experiments in Organic Chemistry and Physical Chemistry, which may properly be taken up in later years of work, have been studiously avoided. If the student’s interest is developed by studying intensively those phenomena which are essential to the thorough development of the subject, he may be intrusted to obtain later those things which naturally follow, but which he might only imperfectly understand if treated in his first year. Their novelty will then add to the student’s zest. “On the other hand, the principles of Physical Chemistry have been freely introduced wherever they seemed necessary to the understanding of the subject in hand, but with as little technical language as possible. Likewise a few quantitative experiments have been introduced which relate directly to the laws which must be mastered during the first year. “The instructions have been made full, so that no good excuse may be offered for slovenly work, and that a t the beginning the student may gain that invaluable technique which can scarcely be lcarned after bad habits have been f ormed .” Ii‘ilder D . Railcroft

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Pure Foods. By j o h n C. OlseM. 13 X I 9 cm: 210 p p . Gii7n and Companj,: New I’orL.-In the preface the author says: “This volume is the outgrowth of a series of public lectures on foods, which have been given by the author for a number of years. The interest shown by audiences of widely different character, as well as frequent requests for the substance of the lectures in printed form, has led to their publication. The

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experimental illustrations which accompanied the lectures are given in the form of a series of experiments a t the end of each chapter. Some of these experiments are so simple that they may be carried out with ordinary household utensils, others require a few chemicals and simple apparatus which may be purchased a t any drug store. Many of them require a fairly well equipped chemical laboratory, while others have been included which can be performed only by those who have considerable chemical training and facilities a t their command. Most of the descriptive matter can be understood by the average intelligent reader although even here a knowledge of chemistry will enable the reader to comprehend the subject much more fully.” “Of the great need of a wider and fuller knowledge of the nature and functions of the food which is of such vital necessity to us, the author has the keenest realization. In an age when intelligence and knowledge are recognized as essential to the most efficient performance of even very simple tasks, i t is S U P prising that most of us eat what we like, with very little thought of the ultimate result. “The steel for our bridges and buildings is bought and sold on the chemist’s certificate of its composition to the thousandths of percent. Foods are manufactured and sold on flavor and appearance, utterly regardless of composition or food value. The coal for our engines must be tested and analyzed, but the far more precious human organism is loaded with a heterogeneous mixture of fuel of unknown composition, We should not be surprised a t low efficiency, inability to work, sickness, even the premature death of an organism which is given so little intelligent care. When an intelligent, well-informed public demands analyzed, tested foods, they will be better served by the food producer, manufacturer, and salesman; and if such food is consumed in the physiologically proper quantity and variety, there will be far less inefficiency, sickness, and mortality. ” The subject is treated under the following heads: What is food?; what is pure food?; standard rations and the cost of food: milk; bacteria in milk; fats and oils; butter and its substitutes; meats; carbohydrates; candies; aniline dyes and other food colors; preservation of foods; fruits, jams, and jellies; fresh and canned vegetables; bread and the cereals; leavening agents; spices and condimental foods; flavoring extracts. The author has written a very interesting book and one that can be recommended. The reviewer is a little sceptical as to the great importance of the calorific value of foods: but the author is quoting from standard authorities, so he cannot be held responsible. One wishes also that the author might have given some explanation of the following paragraph, p. 61. “If an oil is kept a t a low temperature for some time, it separates into two constituents, one of which is solid and the other liquid. The solid constituent can be separated by filtration from the liquid fat or oil. If the two constituents are allowed to remain together and the mixture warmed, the solid melts so that the oil resumes its original appearance. Its properties are not quite the same as before. I t is a well-known fact that olive oil which has been frozen will not make as good a salad dressing as the unfrozen oil.” Il’ildev D. Bancrojt