REVIEWS OF BOOKS. Stoichiometry. By SIDNEY YOUNG, D.Sc., F.R.S. (Textbooks of Physical Edited by SIR WILLIAM RAMSAY, K.C.B., F.R.S. (London : This book commences with an Introduction to the Study of Physical Chemistry by Sir William Ramsay, which takes up 50 pages. This Introduc- tion has already appeared and can be obtained separately, consequently it is not necessary to review it here. The book begins with a discussion of the Fundamental Laws of Chemical Combination, the first portion being more or less historical. Under the definition of an element the author remarks that from time to time it has been suggested that bodies now classed as elements have, in the first place, been formed by the condensation of one or a few primary forms of inatter- in other words, that the elements are either polymers or a very stable form of compound.It has been practically proved that radium emanations gradually become degradated into helium, and if radium is taken as an element, then it must either be a polymer of helium or else a compound of helium with some other yet undiscovered element. Of course, the idea that elements are built up from one primordial substance is not new. It will be strange if increased knowledge finally shows that the conception of the older chemists was more accurate than the theories of those who follow them. The chapter goes on through the Law of Definite Proportions to the Atomic Theory, which, to our minds, is written in an unnecessarily abbreviated form. The next chapter deals with the general properties of gases and then follows the determination of atomic weights.The author lays stress upon the experimental errors which, even when the greatest care is employed, almost invariably occur, and he remarks that no observer, however expert, can hope to obtain absolute accuracy in any measurement, however simple. Consequently one has to work in such a way that a large number of deter- minations are made and the arithmetical mean of the individual values is taken as the final result. Before anyone who has not already taken up the study of atomic weight determinations commences work of this kind he would be well advised to read this section. The next chapter deals with the periodic system of the elements, tables and diagrams being given to show the various relationships of the elements to each other.Thus there is one table which is not usually come across in textbooks on chemistry-the table of hydrides and. halides, and the electro- chemical character of the elements is also indicated by another table. The properties of liquids are dealt with very fully and also the kinetic theory of gases, the properties of solids, and the properties of dilute solutions. The freezing-point and boiling-point methods for determining the molecular weights are fully gone into, and the last part of the chapter deals with Osmotic Pressure. Chemistry). 1go8. Pp. lxi. + 381. Price 10s. Longmans, Green & Co). I43144 REVIEWS OF BOOKS In the last chapter the determination of molecular weights from chemical considerations is considered, the different methods by which the determina- tions are carried out being given.This book is a very useful addition to the series of textbooks of physical chemistry, and the author is to be congratulated upon the care which he has taken in compiling the matter and the success which has rewarded his efforts. Sir William Ramsay’s object in editing this series of books is to cover the whole field of physical chemistry thoroughly, and his hope is that by bringing the books out in the form of volumes under different headings and by different authors, instead of making one complete book, the final result will be less cumbersome, more thorough, and the subjects may be kept more up to date. Whether this is altogether an advantage to the average student who has an enormous amount of work to digest it is difficult to say.That it is of very great value to have such memoirs there is no doubt, but there is a tendency sometimes for disconnection, and may there not be a fear on the part of the authors that they are treading upon ground covered or to be covered by some one who is writing a different volume of the series ? As a rule we have not noticed this to any great extent, but it must be admitted that occasionally this tendency is noticeable. The Construction and Working of Large Gas Engines. BY P. R. ALLEN. This small octavo volume of 120 pages and 7 plates is the reprint of a paper read before the Manchester Association of Engineers on January 11, 1908, and it would have been better if the author had given this information on the title-page instead of burying it in an obscure part of the book where it can only be found after prolonged search.The reprint suffers also from the absence of any division into chapters and from the lack of an index. Having made these criticisms on the form in which the author has pub- lished his monograph, the writer can now devote himself to commendatory remarks. The contents of the book are described with exactness in the title, and the author has dealt in a most practical manner with details of the con- struction and working of large gas engines-that is, of engines of more than 500 h.p. The arrangement and size of cylinders for large powers on the Otto Korting and Oechelhauser systems, flywheels, stuffing-boxes, ignition apparatus, lubrication, starting the engine, silencers and exhaust heat apparatus, and gas-engine troubles are all dealt with, in considerable detail.An appendix gives details of the cost of power by steam and gas and also a tabulated statement of the dimensions of the principal parts of a 750-h.p. engine by various makers. The following paragraphs give the author’s views on the future of the large gas engine :- “The small gas engine occupies a sphere of usefulness of its own ; it is generally relatively economical compared with other motors and requires but little attention, but its strong point is its convenience. The large gas engine has to justify its exist- ence under much mcre onerous conditions, and in meeting the large steam engine has to compete with a machine which has had more than a century of close atten- tion from the most able engineers of the day.Although the large gas engine has developed in a phenomenal way during the past ten years, much remains to be investigated on the theoretical side, while no finality has yet been reached froin the point of view of the builder ; but even in its present condition the large gas engine has attained a sufficient degree of perfection to recommend itself not only to theREVIEWS OF BOOKS I45 manufacturer who wishes to cut his coal bill in half, but to the political economist on the broader ground that any prime mover which will tend to prolong the life of our chief national asset-the British coalfields- is a machine which will be of great assistance to the State.” It only remains to be added that the book is well printed, that the illustra- tions are good, and that it is well worth a place in the technical library of all interested, either as makers or users, in the modern gas engine.Monographien iiber angewandte Elektrochemie. Vol. XXX. Thermoelemente and Thermosaulen. By Dr. FRANZ PETERS. (Halle : Wilhelm Knapp, 1908. Thermo-elements are now so largely employed in electro-chemical and chemical industries that the introduction of a book upon the subject is a valuable addition to the Monographs on Applied Chemistry. The fact that two dissimilar metals when joined together will give an electrical current when heated at the junction was shown so far back as 1801 by Ritter. Seebeck in 1821 showed that when a copper plate and a rod of bismuth were soldered together on heating the junction a current was produced which caused a movement of a magnetic needle.The action of heat upon metals when joined together has been employed-- I. To form a thermo-battery from which electrical energy can be obtained. 11. As a means of measuring temperature, particularly high ones where an ordinary thermometer cannot very well be employed. Dr. Peters first describes the thermo-batteries. The first chapter deals with the history of thermo-electricity. In the next section the construction of the thermo-batteries is treated of. It is shown how different metals and different combinations of metals and alloys can be used, and it is likewise ex- plained which are the most satisfactory and which form of apparatus gives the best result. Although this part of the book is very interesting and is ably written, we are inclined to think that the final part, dealing with the employ- ment of thermo-elements for measuring temperatures, is the more valuable.Pyrometers were at one time very expensive because almost the only metals employed in their construction were of the platinum group-for example, platinum and an alloy of Rhodium-platinum or platinum iridium. Now, however, that cheaper alloys have been found to act satisfactorily-for example; those used in the Bristol pyrometer-this form of measuring instru- ment is being very widely employed. This book is a most useful addition to the already valuable series of volumes upon applied electro-chemistry. It is well illustrated, and the author has evidently been at great pains to make it a complete survey of the subject.Pp. vi. + 184.) Monographien uber chemisch-technische Fabrikations Meth- oden. Vol. XI. Der Dampf in der chemischen Technik. By W. MOMBER. The importance of steam in chemical manufacturing processes cannot readily be over-rated, and it is therefore a very good idea on the part of the publishers of these technical monographs to issue a volume dealing with this subject. The book before us commences with a note upon the various purposes for which steam is employed. The author then refers to the physical nature of (Halle : Wilhelm Knapp, 1908. Price M. 3, P. 60.)REVIEWS OF BOOKS steam, partly in rather an elementary manner and partly in a more advanced way. He then treats of fuel and gives a table showing the number of calories given off by various fuels, such as ordinary coal, peat, wood, petroleum, producer gas, and so on.The various forms of boilers are then described, and we notice-and perhaps it is to be expected-that the German plant are described in greater detail than those of other countries. I t is mainly in connection with boilers, such as are used for steam engines, that this part of the book is written. The next section treats of steam turbines, a subject which one would hardly have expected to have met with in a volume of this title. But a moment's consideration shows that this is not really out of place, because, of course for power purposes, steam turbines are now coming into very general use. The various evaporating plant are then dealt with, and heating with steam under pressure such as autoclave work.Methods of evaporation, of rectification, and distillation in currents of steam also find a place in this monograph. This will certainly be found very useful, but it would have been much more valuable if the author had supplied an index. Canada : Department of Mines-Summary Report of the Mines The Report, which is of considerable general interest, includes a short account of recent progress in Electric Smelting. Among lately-invented systems the Lash process for the direct production ,of steel, which is being tried at Niagara Falls, is described. The typical Lash charge consists of 5.1 per cent. iron ore, 27 per cent. cast-iron borings or granulated pig-iron, 4 per cent. sawdust (to make the mixture porous), 4 per cent.limestone, 3 per cent. coal-tar, and 8 per cent. coke. Successful results have been obtained, it is claimed, heating this mixture direct in the electric furnace. The Electro-Metal Company (Ltd.) are building a 500-h.p. Hkroult furnace at Welland, Ont., and if this is successful larger furnaces will be immediately built. At Nelson, British Columbia, a Snyder induction furnace for the produc- tion of lead bullion and spelter in one operation has been erected, power being supplied by the Bonniiigton Falls. The Report includes an Appendis by Mr. A. Gronwall on a comparison of the various induction furnaces (Kjellin, Frick, Rijchling, and Electro-Metal Co.) at present in use. Apropos of induction furnaces, reference is made in the Report to the observation of Dr.A. Schmidt that the desulphurisation in the Kjellin furnace is to be ascribed to the iron oxides added and to the specific influence of the alter- nating current, which produces, it is stated, molecular oscillations in the bath, rendering more active the combination of the sulphur in the bath and the oxygen of the added ore. Branch, 1907-8. (Ottawa : 1908. Pp. 100. Price 10 cents.) Laboratoriumsbucher fur die chemische und verwandte Indus- trien. Vol. 111. Laboratoriumsbuch fur die Industrie der Riechstoffe. By DR. OSKAR SIMON. (Halle : Wilhelm Knapp, 1908. Pp. vi+67. Price 3 marks.) This little monograph will be found very valuable in the laboratory, for which, of course, it has primarily been written. It commences with a general description of the methods employed in the examination of ethereal oils and perfumes.The section is divided up under the different headings : Physical Methods, Chemical Methods, Examination of some Ethereal Oils,REVIEWS OF BOOKS I47 Identification of some of the chief adulterants which are found in Ethereal Oils. The second part deals with the particular methods employed, and a short notice upon the most important perfumes. The sub-divisions of this part are : Ethereal Oils, Natural and Synthetical Chemical Individuals, Balsams and Resins, Animal Raw Products. The descriptions of the various individual products given and the physical constants lwill be found very useful for purposes of identification, and we congratulate the author upon his work. The N a t i o n a l Physical L a b o r a t o r y : Report for t h e Year 1907. There is much among this record of splendid work accomplished or promised that is of special interest to the electrochemist.In the Physics Department work on the silver voltameter and the electrochemical equivalent of silver has been carried on by Mr. F. E. Smith, in conjunction with Mr. T. Mather, F.R.S., and Dr. T. M. Lowry. It is concluded that an easily reproducible voltameter can be specified, and in this form the passage of a coulomb of electricity always causes the deposit of a definite mass of silver, and that therefore the ampere can be defined accurately to I part in IOO,OOO. It is interesting to note in this connection that the ampere (and not the volt) was chosen as the second primary standard at the recent Inter- national Conference.This work is being continued during the present year, especially with a view of elucidating the differences in the results obtained by other observers. In the same Department work on the Weston cadmium cell has been con- tinued, and it is concluded that this standard cell can be set up by different people with different materials and still have E.M.F.’s agreeing to a few parts in IOO,OOO. In the Photometric Department the reproduction of the Violle standard of melted platinum is in contemplation, and in view of this the valuable work of Dr. Harker, who is constructing large electric refractory-oxide tube furnaces of the cascade type, will prove of special importance. This brings us to the Thermometric Department, where Mr. W. A. Price has been im- proving carbon tube furnaces, and has evolved a form capsble of heating uniformly fairly large objects up to 2,500~ C.In this the melting and boiling points of a number of refractory substances are being studied, and this work is now being continued in the new fire-proof room specially erected for the purpose of high-temperature research. This will include investigatioiis into the pro&rties of fused silica ware and the strengths of other materials at high temperatures and a special electric furnace with automatic photographic temperature recorder has been installed for the purpose. Other high- temperature work is being carried out in the Moissan arc furnace and the Grondel-Kjellin furnace, in which the behaviour of metals and alloys can be studied in the absence of flame gases.The Metallurgical Department is now the permanent home of the investi- gations undertaken by the Alloys Research Committee of the Institution of Mechanical Engineers, whose work last year was concerned with the alloys of copper and aluminium, and of certain ternary alloys of aluminium. The latter investigations are being carried on, as are also the eutectic alloys researches of MI-. Rosenliain and Mr. Tucker. In the new building for metallurgical chemistry, which is now open, a modified form of Dr. Sand’s apparatus for the rapid electrolytic determination and separation of metals has been installed.REVIEWS OF BOOKS Introduction to Metallography. By Dr. PAUL GOERENS. Translated by FRED IBBOTSON, B.Sc., A.R.C.Sc.1. (London, 1908 : Longmans, Green & Co., 39, Paternoster Row, E.C. Price 7s. 6d. net.) This is an admirably clear exposition of the physico-chemical principles underlying the study of the minute structure of metals, the statement of general theory and its application to particular cases leaving little to be desired in the way of lucidity. An introductory chapter on Cooling Curves and their determination leads up to a discussion, first of Aqueous Solutions, then of Solid Solutions (fused salts), and finally of Alloys. This last chapter covers a very wide field, dealing, in brief, with practically all the binary and ternary combinations that have been studied up to the present. A useful chapter on the Practical Microscopy of Metals and a final chapter, well illustrated, on the Metallography of Iron and its Alloys complete the volume. The book contains a few faults of style incidental, perhaps, to the transla- tion, and some omissions due to the English version (except the last chapter) not having been brought quite up to date, but apart from this it will make an excellent text-book for men beginning the study of a difficult subject, which it tackles in a clear, interesting, and practical manner. Pp. 214.