RECENT BOOKS PROUT'S HYPOTHESIS.ALEMBIC CLUB R ~ P R I N T NO. 20. Papers by William Prout, M.D. (1815-16). I. S. Stas (1860). and C. Marignac (1860). Edinburgh: Published by the Alembic Cluh. Edinburgh Agents: Oliver and Boyd, Tweeddale Court. London Agents: Gurney and Jackson, 33 Paternoster Row. 1932. 58 pp. 18.2 X 12.2 cm. $0.65. Prout's Hypothesisthat the atomic weights of the elements are multiples of that of hydrogeu--dates from the papers which Prout published anonymously in 1815 and 1816 in Thomson's A n m k of Philosophy. The first of these, entitled "On the Relation between the Specific Gravities of Bodies in th& Gaseous State and the Weights of their Atoms," contains more than a suggestion of Avogadro's Principle. The second paper is shorter and was written for the purpose of correcting an error in the first. Both are reprinted in the present Alembic Club Reprint, along with extracts from a paper of Stas (1860). which denies the views of Prout, and a paper of Marignac (1860) which aiticizes the paper of Stas and defends the hypothesis of Prout. The extracts from Stas end as follows"1 conclude then by saying: as long as we hold to experiment for determining the laws which regulate matter, we must consider Prout's law as a pure illusion, and regard the undecomposahle bodies of our globe as distinct entities having no simple relation by weight to one another. The incontestable analogy of properties observed amongst certain elements must be sought in other causes than those originating in the ratio of weight of their reacting masses." In spite of the experimental results of Stas. Marignac was convinced that the fundamental prin&iple of Prout's Hypothesis was valid. His paper contains a prophetic passage foreshadowing the idea of a ''packing effect" which Aston has recently stated as follows. "In the nuclei of normal atoms the packing of the electrons and protons is so close that the additive law of mass will not hold and the mass of the nucleus will be less than the sum of the masses of its constituent charges." Marignac argued in 186&"Could we not suppose that the cause (unhown but probably different from the physical and chemical agencies familiar to us) which has determined certain groupings of the atomq of rimo or dial matter so as to rive rise to OW -~ the sole -~~ chemical atoms, by imprersing on each of thew groups a special chnncter and particular properties, should not at the same time have exercised an intluence on the manner according to which these groups of primordial atoms would obey the law of universal attraction, in such wise that the weight of each group might not be exactly the sum of the weights of the primordial atoms composing it?" The present Alembic Club Reprint contains a feature which is an innovation in this series of reprints, an Historical Introduction, pp. 5-24, which greatly inaeases its interest and value. We think that the Introduction ought to carry the name of the scholar who wrote it, but we are grateful for it neverthelessas we are grateful to the Alembic Cluh for the publication of this latest addition to its series of the classics of chemistry. L. DAVIS TENNEY
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AN INTRODUCTION TO CHEWSTRY.Frank B. Kenrick, Professor of Chemistrv. Universitv of Toronto. The Universitv of 434 pp.. 33 Toronto ~ r e &Toronto, Canada, 1932. viii Figs. 14.5 X 22.75 cm. 8.00. The oumase of this book. as stated in the Preface. is "to interpret in loborolor) terms n numtm of the commoner wards such as constituent, dissolved constituent, compositmn, solution, pure substance, element, atomic weight, molecular weight, chemical formula, ion, dissociation, and same others." A great deal of emphasis is placed on the language of chemistry. The book is divided into nineteen chapters, entitled as follows: "the manufacture of salt, chlorine and caustic soda, meaning of the term constituent substance; composition; the refining of
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crude sugar, unsaturated solutions, supersaturated solutions. solubility, adsorption; the refining of crude sugar (continued). vapour pressure, boiling paint, partial pressure, and partial vapour pressure; mechanical mixtures, solutions, and pure substances; the elements; law of reacting weights, chemical symbols and formulas; water as a type of pure substances; the chemistry of water and of aqueous solutions; the constituent substances of water (oxygen and hydrogen), oxides and salts, valency; aqueous solutions; wood; the mass law, esterification, synthesis of ammonia, dissociation, electrolysis; air; rocks; methods of preparation--general; methods of manufacture, applications of rules of reactions, electrolytic processes; the periodic system of elements, Mendelejeff's table; chemical literature." The order and treatment are a radical departure from that in other textbooks. "A great deal of the traditional descriptive matter has been omitted, and the usual order of presenting it has been modified." We find in Chapter I that brine is pumped into an enormous tank called an evaporator, in which a "slurry" is obtained. Every 100 tons of slurry yield about 40 tons of salt and 60 tons of brine. The latter is subjected to electrolysis, chlorine, hydrogen, and "cell liquor" being obtained. The electrolysis of caustic soda is also discussed, as well as the manufacture of hydrochloric acid; also, the formation of water from hydrogen and oxygen. A great deal of stress is laid on quantitative relations, many equations being given, such as: 92.0 g. cell liquor ---3-
+ 8.78 g. caustic soda + 70.05 g. water.
13.17 g. salt
The author has much to say about a set of constituent substances On p. 18 one finds: "A set of constituent substances of a material is either a set of substances into which the material cm be turned quantitatively or a set from which it can be made quantitatively." His use of the term "constituent substances" does not correspond to general usage, nor to the derivation of the word constituent staluerel. Dr. Kenrick savs: "The term 'a con(Latin constituent substance' may be uscd for one or more substnnccs of a set of constiturnt substanccs." In Chapter 11.32 page. are devoted to compositiou. Raw materials, elementary composition, etc., receive attention. Composition of mechanical mixtures is also discussed. A page (43) is devoted to an alloy of copper and gold; and, long before symbols, nomenclature, etc.. are mentioned, the author speaks of "solid solutious of copper auride and copper." Indeed, symbols of elements are not given until page 170 is reached; brief mention of nomenclature is made on page 205, and valency is discussed on page 256. The author (p. 92) defines a mechanically mixed constituent as follows: "If the solubility of a conslituent of a material is the same as the solubility of the constituent substance, determined a t the same temperature and pressure and with the same solvent that constituent is a mechanically mixed constituent." Dr. Kenrick places pure substances and solutions under the head of non-nziztures (p. 96). He says that air, far example, is not a mchenical mixture of gases. He defines (p. 106) a solution as "an intermediafa member of a continuous series of mn-miztures." Reacting weights (p. 166) are used instead of atomic weights, and the term equivalent or combining weight is not mentioned in the index. The constituents of water (oxygen and hydrogen) are discussed in Chapter X (p. 224). Steel is not listed in the index. Chemical arithmetic is neglected. Enough has been presented to show that "An Introductiou to Chemistry" is unique both as to content and arrangement. While the author clearly shows that he is a scholar. he has given us a book which is somewhat fantastic. A better title would be "Selected Chapters in Chemistry."
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The reviewer regrets that he cannot recommend this book for use as a text. It is not systematically arranged, well-balanced, nor teachable. Indeed, the author says: "The student specializing in chemistry should, of course, read in conjunction with this book mauv others." He also savs: "This will not be found to be a 'teachable' book; a teach;ble book is a learnable hook. and that is a most dangerous educational weapon. Chemistry is not a teachable suhjcct; it is a thing to be struggled with."
CHEMISTRY. J. S. Long. Ph.D., E X P E ~ N TINS INORGANIC Professor of Inorganic Chemistry, and R. D. BiUinger, Ph.D., Assistant Professor of Chemistry, Lehigh University. Times 298 pp. Publishing Co., Bethlehem, Penna., 1932. viii 26 Figs. 13.5 X 21.5 cm. $1.75.
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The number of pages given in the above description is same what misleading. The printed pages number only 149; one side of each sheet is left blank. This laboratory book is designed for one semester's work but a sufficient number of experiments is given to require almost one and onehalf semesters for the average student. It is intended that beginners might omit some of the more difficult experiments and the student from a good high-school course might omit the simpler dnes. Hence this manual will snit both types of students. All of the work usually included in an elementary course is covered here with the exception of that on the metals. Some of the experiments found here and not often in other manuals are: velocity of chemical change illustrated by the HzSO. HIOa time reaction; chamber process for HSO.; preparation of AsH8; a measure of catalysis by the decomposition of HZ%; preparation of Hg(CNS)%. The book is well written and in s~fficientdetail so that it should he easy to follow. It might be better if a few more illustrations were given. Each experiment is followed by an excellent series of questions. C. E. WHITE
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umms1ru 0s M*FSL*ND COGLEG& P A R K , M D .
E X P E R I ~ N T ACHEMISTRY L FOR COLLEGES.J . Allen Harris and William Ure, Assistant Professors of Chemistry in the University of British Columbia. McGraw-Hill Book Co., Inc., New York and London, 1932. x 192 pp. 21 Figs. and 9 tables. 20.5 X 26.5 cm. $1.25.
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The exercises are drawn up for fust-year chemistry students. "The necessity of getting away from the methods of laboratory instruction in elementary chemistry in which the student is asked to perform a large number of short and chiefly qualitative experiments, ending in the sink, is becoming apparent to most laboratory instructors. Such experiments are better suited to the lecture table, and it has heen our experience that the interest of the student can hest be aroused and maintained by giving him a definite objective to attain during each laboratory period, whether it be the quantitative testing of some chemical principle or the careful preparation of some interesting compound. The experiments have also been carefully chosen so that during their execution the student absorbs a considerable knowledge of the chemistry of the process along with valuable experience in technic (such as fractional crystallization and distillation), without the need of separate experiments purporting to illustrate these operations but giving no indication of their importance or value in general chemistry." To the best of the reviewer's knowledge, the hwk is probably the 6rst of its kind lo appear on the market for all first-year chemistry students. He does know of two other manuals with the same numose in mind. hut intended -- for sophomore stndents or students who have had one year of high-school chemistry. Nevertheless there is a need for this kind of manual. The boak contains 22 exercises, each "preceded by an iotrodnctory section which discusses the field illustrated by the experiment, together with the theoretical considerations involved."
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These discussions are of excellent quality and make possible the use of this hook with any standard textbook for first-year chemistryalthough it should be pointed out that there are no textbook references in the hook. The reviewer's estimate of the amount of laboratory time required for the completion of these exercises is about 90 hours. A list of 38 typical chemical prohlems is also included. In these days of economies, it is of interest to note that the authors "have found it quite feasible t o subdivide a laboratory section into four groups of 20 each, each group working on an entirely different experiment." The principle involved is sound, hut the opinion of other experienced teachers is that a group of as many as 20 students working together with one set of apparatus is anything hut wholesome. The leaves are perforated far ready removal from the book and triple-pnnclied for re-filling in any standard notehwk rovera convenient feature. Same of the diagrams are extremely formal in appearance. For example, the student may find a second look a t Figure 17 necessary in order to assure himself that one item in the set-up is t o be of rubber tubing and not glass tubing. The diagram of the common gas burner appears to have been made by fallowing the cut-out design found in s celluloid Harcourt stencil. The beakers have an unusual angularity at the top. The amount of glass tubing required in Figure 14 is uneconomical. The instructions in the diagrams are excellent with a few exceptions, such as found in Figure 17 which calls for sulfuric add whereas the descriptive matter requires hydrochloric acid. The exercises are divided into three groups illustrating: (a) "principles of chemistry"; (b) "preparation of elements and compounds"; and (c) "reactions of electrolytes." In the main the exercises are well chosen. From the discussion it is a little dEcult to understand why there are two adjacent "high-temperature reactions," preparation of potassium permaganate and chromates and dichmmates. Quite a few statements are misleading to the discerning student. On p. 3, "By concentration, we mean the amount of substance present per unit volume." "Two kinds of apparatus are to be used far weighing," yet the two kinds described are merely balances of different sensitivity. "Check your weight by counting the weights." The concept of mlal as found on pp. 3 and 160 in particular is certainly not that of mast chemists. The reader might easily believe that a mrmal solution is the only kind of standard solution. The symbol E representing an electron is first used on p. 92 and the legend is given on p. 100. The use of Arabic instead of Roman numerals for representing valence is to he commended, although there is a reversion on p. 76. In several instances the valence is placed a t the side of the symbol. It is quite comfortine - to 6nd the concentration of acetic acid as the illustration of frmtional distillation instrod of the time-honorrd nlcohol. The use of Na9C02 instead of NaCHOa fur standardization work is perhaps not so good, considering the fact that the remaiudcr of the exercise is to be done with considerable accuracy. The hook should be on the desk of evetv teacher havine laree groups o' students who hove had at least onc year of high-school chcmistrv, e t e n though a number of the pracedurcs arc doubtlers quite familiar to many teachers of first-year students.
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ELEMENTARY QUALITATIVE ANALYSIS. J. H.Reedy, Associate Professor of Chemistry in the University of Illinois. Second edition, McGraw-Hill Bwk Co.. Inc., New York City, 163 pp. 13 Figs. 20.5 X 14 cm. $1.50. 1932. x
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The purpose of the author in the second edition of this boak appears to be to place in the hands of the student a set of reliable laboratory directions and, a t the same time, leave ample opportunity for interpretation of results. Part I takes up the analysis of the cations. Directions far preliminary tests are first given which are followed by directions
