determined by assuming that the rate of seaward advance of the delta as determined for the past 60 years has been uniform during the time of formation of the delta, and dividing the rate into the distance of advance of the delta. The average distance from the inner edge of the delta along the highland below New Westminster to the seaward front of the delta is about 80,000 feet. Dividing this by 10 feet gives 8,000 years as the age of the Recent delta. It is possible, however, that the rate of advance has varied in the past and that part of the delta above New Westminster was formed in Recent time. Hence these figures have little absolute value, but they seem to show, nevertheless, that the relationship of sea and land in the Fraser delta region has been nearly if not quite stable for several thousand years and that the last uplift of the land or lowering of sea-level took place probably not more than 10,000 to 12,000 years ago. The writer is indebted to the late Commander Musgrove of the Department of the Naval Service of Canada, under whose direction the soundings in the strait of Georgia were made in 1919, for records of the soundings; and to Mr. W. H. Boyd, Chief Topographer of the Geological Survey, Canada, who correlated the soundings in 1859 and in 1919 and determined the rate of advance of the delta. SCIENTIFIC INTELLIGENCE. I. CHEMISTRY AND PHYSICS. 1. The Separation of Gallium from Indium and Zinc by Fractional Crystallization of the Casium-Gallium Alum.-The separation of gallium and indium by this method was briefly described by Uhler and Browning in this Journal in 1916 (42, 389). This method has now been studied quantitatively by PHILIP E. BROWNING and LYMAN E. PORTER. Starting with 7.5 g. of mixed hydroxides containing 26.5 parts of gallium oxide to 73.5 parts of indium oxide, they dissolved this in sulphuric acid, added a little more than the theoretical amount of cæsium sulphate, neutralized most of the free acid with sodium hydroxide, ad then crystallized from a volume of 250 cc. The first crop gave a product with 85.1 parts of gallium oxide to 14.9 parts of indium oxide. After five recrystallizations, the crystals at the least soluble end consisted of pure cæsium-gallium sulphate, while the fifth mother-liquor contained gallium and indium oxides. in the ratio of 0.6 to 99.4. It was found that when 1 g. of pure cæsium-gallium alum was mixed with 0.2 g. of zinc oxide dissolved in sulphuric acid and with 0.1 of cæsium sulphate a single crystallization gave a product with 98 parts of gallium oxide to 2 of zinc oxide, while a recrystallization of this gave a crop in which zinc could not be detected. The results show that the method is an excellent one for the purpose.-Jour. Amer. Chem. Soc., 43, 126. H. L. W. 2. A Text-Book of Practical Chemistry; by G. F. HOOD and J. A. CARPENTER. Large 8vo, pp. 527. Philadelphia, 1921 (P. Blakiston's Son & Co. Price, $5.00 net).-This is intended to be a reference book for students in connection with experimental laboratory courses. It embraces inorganic preparations, qualitative analysis, quantitative analysis, organic preparations, organic analysis, and physical chemistry, and in each of these main sections there is a careful classification of the matter presented, so that by means of suitable chapter-headings easy reference is assured. The book gives a favorable impression as a very useful one for students and teachers in laboratory courses, for it gives a vast amount of accurate information in regard to laboratory experiments in various courses of study. Naturally there are differences of opinion in regard to the best methods of procedure in certain operations. For instance, this book states that it is undesirable to use the Gooch crucibles for precipitates that have to be ignited, it recommends the use of gentle suction only in employing it, and it advises the introduction of a perforated porcelain filter plate between two layers of asbestos when preparing it for filtration; whereas, there is no doubt that precipitates may be ignited to redness in the Gooch crucible with the most satisfactory results, that strong suction is desirable to prevent the displacement and running through of the asbestos, and that the filter plate is superfluous when strong suction is used. In view of these facts it appears that some, at least, of the British chemists are not taking full advantage of the important American device, the Gooch crucible. A good feature of the book is the introduction at the end of each main section of references to the literature of the subject, such as monographs and text-books. H. L. W. 3. A Dictionary of Chemical Solubilities, Inorganic; by ARTHUR MESSINGER COMEY and DOROTHY A. HAHN. 8vo, pp. 1141. New York, 1921 (The Macmillan Company).-This work is to be welcomed as an exceedingly important addition to chemical books of reference. The first edition, by Dr. Comey alone, appeared 23 years ago, and much material has accumulated since that time, as is shown by the fact that this second edition has more +1 twice as many pages as the earlier one. Comey's dictionary gives full quantitative data regarding the solubility of inorganic substances, as well as the specific gravities of solutions in many cases, but the unique feature of the work is the fact that it attempts to mention and give the formula of every inorganic compound that has been analyzed. This last feature gives the book a particular importance and usefulness as a book of reference, for it affords an alphabetically arranged list of all the inorganic compounds with references to the original literature. In many cases little is known about the solubility of the compounds, but even the statements given in such cases, showing that they are soluble or insoluble in water, soluble or insoluble in certain acids, decomposed by water, etc., are frequently very useful items of information to chemists. Comey's dictionary is based in plan upon that of Professor Storer, published in 1864, which some of our older chemists remember as an interesting and important source of reference before the time of the appearance of the more modern work under consideration. The great amount of labor involved in the preparation of this dictionary deserves much praise, and it appears that the effort was well worth while in producing a book of such usefulness. H. L. W. 4. Inorganic Chemistry for Schools and Colleges; by JAMES LEWIS HOWE. 8vo, pp. 443. Easton, Pa., 1920 (The Chemical Publishing Co.).-This text-book now appears in its revised second edition, thirteen years after its first publication. In the presentation of the subject much attention is paid to the Periodic Law. For instance, separate chapters are devoted to the elements, the hydrides, the halides, etc., in each case with arrangements according to the periodic groups. There are undoubtedly some advantages in this plan, but it brings the descriptions of the metals and their various compounds into several different parts of the book. The book presents the fundamental principles and facts of chemistry very clearly, and it is admitted that there is much intentional repetition in order to facilitate thorough teaching. The practical applications of chemistry are rather fully treated and at the end of the book three is an excellent chapter on metallurgy. A course of simple but instructive laboratory experiments is given by means of concise directions in small print at the bottoms of the appropriate pages. The author states that he has made no attempt to incorporate many of the recent advances in chemistry into his elementary book, but, nevertheless, in view of its importance in connection with the atomic theory, it is somewhat unexpected to find no reference to radioactivity when radium is mentioned and to find niton omitted from the periodic table. H. L. W. 5. Luminous phenomena in the Lilienfeld tube.-The peculiarity of the Lilienfeld X-ray tube is that the electrons emitted from the hot filament after passing through a small hole in the main cathode are accelerated in a strong field and may be brought to a very sharp focus on the target which is inclined at an angle of 45° to the path of the beam. The authors of this paper, J. E. LILIENFELD and F. ROTHER, report the formation of a luminous ring of light, blue-gray in color, and of elliptical form, just at or above the surface of the anticathode. The size of the ellipse increases with higher potential discharges but remains similar in form. Examined with a polariscope the light is almost completely plane-polarized with the electric vector parallel to the line of intersection of the plane of symmetry of the tube with the surface of the target. The spectrum was similar to that which would have resulted from a high temperature but with limits dependent somewhat upon the conditions of excitation of the tube. The intensity of the short wave end compared to the long wave end was so very much greater than with ordinary light sources as to imply an exceedingly high temperature. It is their idea that the radiation arises in an electron layer just at the front of the anticathode, which is excited by the cathode rays and that the connection between this layer and the electrons lying a little deeper in the plate is so close that the visible spectrum probably passes over uninterruptedly into the continuous Roentgen spectrum. The paper is illustrated with photographs of the spot and its spectrum together with comparison spectra from helium and a metal filament. Phys. Ztschr. 21, 249, 1920. F. E. B. 6. Observations on Soaring Flight.-Although the exact nature of soaring flight still remains an unexplained problem of physics a summary of observations by DR. E. H. HANKIN extending over a period of ten years and recently communicated to the Cambridge Philosophical Society is deserving of attention. The observations were carried on in a tropical country where the meteorological conditions are more stable than in temperate latitudes, and were made not only upon birds, but also upon dragon flies and flying fishes. The two points of novelty in the author's view are, (1), that the wing sections of the best soaring birds and in the soaring dragon flies are characterized by transverse ridges projecting on the under side of the wing. A similar feature is significantly present in the puttung, a form of Indian kite which flies vertically over its string; (2), that the slow soaring flight in all three classes of animals is seemingly dependent upon the presence of sunshine, while fast soaring flight is always dependent upon the presence of wind. That soaring flight is not due to undiscovered wing movements is a conclusion drawn from the means used to brake the flight in the case of dragon flies and of flying fishes. Arguments are presented that soaring flight is neither due to lateral gusts of wind, to ascending currents nor to turbulencies whose presence could be detected by the motion of small masses of discrete cloud material, the behavior of numerous floating seeds, or small floating feathers. It is the author's conclusion that since the most attentive observation has failed to suggest a solution of the problem, the only hopeful method of attack is by way of direct experimental investigation. A list of twelve articles detailing the author's observations is appended to the communication.-Proc. Camb. Phil. Soc. 20, 227, 1920. F. E. B. 7. Elementary Calculus; by WILLIAM F. OSGOOD. Pp. ix, 224. New York, 1921 (The Macmillan Co.).—A new text on Elementary Differential Calculus which aspires to attention in this well-occupied field should present some special claim to recognition. The author's aim to present the subject with emphasis on the ideas and methods of the calculus and their use in solving problems in physics and geometry, is well maintained. The tendency of the student to regard differentiation as a mechanical process whereby an answer is to be obtained is strongly deprecated and the illustrative examples are so selected that they should seem to him as of interest and value. More than usual pains has been taken to make the logic rigorous, which will doubtless appeal to the mathematicians. On the other hand the illustrations used are so concrete and physical that they afford the very kind of mathematical training which the physics teacher desires his students to have had. Of the eight chapters, one describes the character of the simple functions, and five are devoted to the manner and result of their differentiation. Chapter II discusses the application of derivations to curves, to maxima and minima, to velocity and to rates. Chapter VII is the most unusual in a book of this scope. In it is presented a valuable discussion of the methods of graphical solution and approximation for numerical equations which do not come under the standard rules of algebra and trigonometry. It is a book which merits the attention of teachers of Freshman courses in colleges and technical schools. F. E. B. 8. Space, Time and Gravitation; by A. S. EDDINGTON. Pp. vii, 218. Cambridge, 1920 (Cambridge University Press).The author is one of the most prominent of the English protagonists of the relativity theory. The purpose of the book is to expound the theory and its implications without the use of much technical mathematics, but with strong emphasis upon the rightness of the author's view. The polemical character of the book is evident in the introductory chapter which is cast into the form of a dialogue between a physicist, a mathematician, and a relativist, in which the physicist becomes somewhat involved in a metaphysical fog. The first three chapters are devoted to the Fitz-Gerald contraction and the geometry of the space-time manifold. The next three chapters show how on the equivalence theory all the forces |