mountains. He was, from the outset, a most energetic tion of Solanum tuberosum. An account of experi- ments in the cultivation of wild potato plants from Chile, Bolivia, and Peru. The tubers produced from the cultivated plants were edible, and contained a greater amount of starch than the wild plants. The tubercles from Bolivia showed the characters of muta- tion; those from other sources appeared to be in course of mutation.-W. H. Young: The summability of a function of which the Fourier's series is given.- B. Bianu and L. Wertenstein: An ionising radiation, attributable to the radio-active recoil, emitted by polonium. It was found to be necessary to use a polonium film in these experiments not exceeding 10μμ in thickness. The curves obtained with a silver disc covered with this thin polonium layer, in presence of a analogous with those obtained in the case of radium C, States. By Prof. S. J. Record. Pp. 6 plates. (New York: J. Wiley and Sons; London: Chapman and Hall, Ltd.) 5s. 6d. net. Forestry in New England. By Profs. R. C. Hawley and A. F. Hawes. Pp. xv+479. (New York: J. Wiley and Sons; London: Chapman and Hall, Dove Marine Laboratory, Cullercoats, Northumber land. Report for the year ending June 30, 1912. New Series. I. Edited by Prof. A. Meek. (New- castle-on-Tyne: Cail and Sons.) 5s. Catalogue of the Periodical Publications including the Serial Publications of Societies and Governments in the Library of University College, London. By L. Newcombe. Pp. vii+269. (Oxford: H. Hart.) Catalogue of the Periodical Publications in the Library of the Royal Society of London. Pp. viii- Results of the Magnetical and Meteorological Ob- servations made at the Royal Alfred Observatory, Mauritius, in the year 1902. Pp. xxii+lxxviii+ 5 plates. Ditto, 1903. Pp. xxi+lxxiv +7 plates. Ditto, 1908. Pp. xxv+lxxxviii+6 plates. (Mauritius.) An Introduction to the Study of the Protozoa, with Eugenics and Public Health. By Prof. K. Pearson. Pp. 34. (London: Dulau and Co., Ltd.) IS. net. Darwinism, Medical Progress, and Eugenics. The Instinct and Experience. By Prof. C. Lloyd Morgan. Pp. xvii+299. (London: Methuen and Lebensbild eines Naturforschers. By E. du Bois- Reymond. Zweite Auflage. Pp. 50. (Brackwede i.W: Dr. W. Breitenbach.) So pfennigs. The Boy's Playbook of Science. By J. H. Pepper. Revised, &c., by Dr. J. Mastin. Pp. x+680. (London: G. Routledge and Sons, Ltd.) 5s. Dana's Manual of Mineralogy. Thirteenth edition. By Prof. W. E. Ford. Pp. viii+460. (New York: Notes on Algebra. By A. F. van der Heyden. Ltd.) 2s. 6d. Exercises in Modern Arithmetic. By H. S. Jones. British Rainfall, 1911. By Dr. H. R. Mill. Pp. Life Understood from a Scientific and Religious Point of View, &c. By F. L. Rawson. Pp. xv+660. THURSDAY, SEPTEMBER 12, 1912. THERMODYNAMICS OF THE ATMOSPHERE. Thermodynamik der Atmosphäre. By Dr. A. Wegener. Pp. viii+331. (Leipzig: J. A. Barth, 1911.) Price 11 marks. tant both in the general circulation and in local disturbances, and it is usually put forward as the explanation of the Föhn. The cooling of the air which rises on the windward side of the mountains is influenced by the condensation and precipitation of the water which it contains. This air descends on the lee side, where there is no moderating effect on the vertical temperature Tintellectual calibre of the men who pursue HE progress of a science depends upon the gradient, and is consequently hot and dry. on it that determines what shall be written for them as well as by them. It is therefore significant for meteorology that a text-book on the thermodynamics of the atmosphere should be added to a collection recently enriched by treatises meteorological optics and on the foundations of dynamical meteorology. Special phases of the subject have been treated at some length by Helmholtz, Hertz, von Bezold, and others, but their papers are scattered among different scientific journals, rarely accessible in a single library. Dr. Wegener's treatise, which has been written. with the object of giving a systematic account of the existing knowledge and methods, should therefore be generally welcomed. In an introductory chapter the author deals with the constitution of the atmosphere, and discusses in interesting fashion the extreme heights at which various optical phenomena, aurora, meteors, and zodiacal light appear. He finds that in all cases the values lie roughly between 70 and 100 km., or in the layer in which the nitrogen atmosphere is changing to the hydrogen atmosphere. After an account of the thermodynamics of an ideal gas and its application to a consideration of the precise proportions in which different gases exist at different heights, he indulges in some speculation about the existence of a hypothetical gas, geocoronium, above the hydrogen atmosphere. Such speculation is out of place in a text-book, and the same criticism applies to the statement that the stratosphere extends from 11 to 70 km. There is no evidence as to the upper limit of the temperature conditions characteristic of the stratosphere. In the third section the different phases of water vapour, the condensation on nuclei, and the formation of crystals are discussed thoroughly and comprehensively. The fourth and fifth sections, which comprise rather more than two-thirds of the book, are undoubtedly the most valuable parts of the work. In them the author treats of the thermodynamics of adiabatic changes and of the physics of clouds respectively. The effect of the condensation of water vapour in diminishing the vertical temperature gradient for air rising adiabatically is impor Dr. Wegener deduces, from the fact that the average vertical gradient is less than that corresponding to the adiabatic gradient either for saturated or for dry air, that the rising of the air on the windward side actually exerts a moderating influence on the Föhn. A very full account is given of "inversions," i.e. cases in which the temperature remains constant or increases with increasing altitude. Their connection with waves and wave-clouds is discussed at length, and the form of the surface between currents of different densities and velocities is made the subject of mathematical investigation. A chapter is devoted to the stratosphere. The different types of the temperature-height curve between the troposphere and stratosphere are illustrated by an excellent diagram derived by Schmauss from a consideration of the results obtained at Munich. In the discussion of the meteorological conditions in the stratosphere itself it is assumed that the relative humidity at the base of the stratosphere, the region of minimum temperature, is 50 per cent. As there is no process by which the nitrogen-oxygen atmosphere is "dried" except by the precipitation of water condensed by cooling, it is not easy to see how a relative humidity of 50 per cent. could be obtained at the place of minimum temperature, where diffusion and convection would both tend to produce saturation. The discussion of clouds is excellent. It includes a note on the rate of fall of drops and its connection with the passage from cloud to rain. The photographs of the different forms of clouds, some of which were taken from balloons above the clouds, are well reproduced, and add considerably to the educational value of the descriptive matter and the theoretical discussion. Dr. Wegener has performed a signal service in producing a good book on a branch of the subject which had not previously been dealt with systematically. The work as a whole loses by the deliberate exclusion of radiation, which is fundamentally mentally and indissolubly connected with the application of thermodynamic considerations to the problems which confront the meteorologist every day. The author regards it, however, as a subject for separate treatment. THE STORY OF "EIGHT DEER." The Story of "Eight Deer" in Codex Colombino. By J. Cooper Clark. Pp. 33+ plates A-J (coloured). (London Taylor and Francis, 1912.) Price 215. net. A : MONG the papers presented to the International Congress of Americanists during the session held in London at the end of last June was a pamphlet by Mr. J. Cooper Clark entitled "The Story of ' Eight Deer' in the Codex Colombino." This is an attempt to throw some light into the obscurity of the pre-Columbian American manuscripts. Mr. Cooper Clark commenced his researches with a careful examination of the Codex Colombino, a picture-writing painted on prepared deerskin, folded like a screen, and measuring 6'80 metres in length when spread open, now preserved in the National Museum in the City of Mexico. In this manuscript Mr. Cooper Clark traced the history of a warrior chieftain named "Eight Deer." All the personages identified by Mr. Cooper Clark in this codex are named after days of the month, and the name "Eight Deer" is expressed by a deer's head with the numeral eight (that is, by eight round discs) attached to it, a deer's head (Maçatl) being one of the twenty day signs of the Nahua month, and according to the Nahua method of noting time, this date would occur only once in a cycle of fifty-two years. is not, however, explained why this particular day was chosen as the name of the warrior, although it is stated that it was not the day of his birth. It The life-history of Eight Deer is most ingeniously traced through the pages of the codex, but the most interesting fact established by Mr. Cooper Clark is that the history of the same individual is also told in five of the other extant pre-Columbian codices, namely, the Zouche (British Museum), the Vienna, the Bodleian, the Baker, and the Selden. By a careful comparison of these codices, Mr. Cooper Clark has not only been able to show that in part they tell the same story, but to supply incidents in the history of Eight Deer which are missing from the Codex Colombino owing to the destruction of a part of the manuscript. Mr. Cooper Clark has further come to the conclusion that Eight Deer can be identified as the glyph attached to the figure of a warrior carved on one of the stone slabs from Monte Alban in Oaxaca (in the Zapotec country), now exhibited in the National Museum of Mexico, and from this he argues that the codices dealing with the story of Eight Deer must be of Zapotec and not Aztec origin, adding, "Not many Nahua codices are likely to have survived the destruction by Archbishop Zumarraga of the temple libaries of Tenochtitlan, Texcoco, and the other cities around the lakes, whereas, warned by the example of Mexico, the Zapotecs would have had ample time to secrete their records." If There is no difficulty in fixing the dates mentioned in the Codex Colombino within the fifty-two year cycle; the difficulty arises in determining in which cycle of fifty-two years the dates occur. the events depicted are placed in the next cycle before the arrival of the Spaniards, the birth of Eight Deer would have taken place in the year 1491 A.D.; but Mr. Cooper Clark thinks that it more probably took place in the previous cycle, when the date would correspond to 1439 A.D. The pamphlet is illustrated with plates most carefully drawn and coloured from the original manuscripts, showing how the same events in the life of Eight Deer are depicted in the Colombino, Zouche, Bodleian, and Becker codices. Mr. Cooper Clark is to be heartily congratulated on his most painstaking achievement. The pamphlet was written for the few who are interested in ancient American civilisations, and can only be fully appreciated by those who have access to copies of the codices discussed; but even to the general reader it must be of interest as showing a native American method of recording historical events, and, moreover, as demonstrating how, by careful and intelligent examination and comparison, order and meaning may be evolved from the most obscure and unpromising material. SUBMERGED RIVER-VALLEYS. Monograph on the Sub-Oceanic Physiography of the North Atlantic Ocean. By Prof. Edward Hull, F.R.S. With a Chapter on the SubOceanic Physical Features off the Coast of North America and the West Indian Islands, by Prof. J. W. W. Spencer. Pp. viii+41 + xi plates. (London: E. Stanford, 1912.) Price 215. net. TH HIS is a folio publication with eleven excellent maps and nine short chapters of explanatory text, and an additional chapter by Prof. J. W. Winthrop Spencer. The author has based the work on a detailed study of the Admiralty charts showing the soundings over the continental shelf and the upper part of the continental slope off the western coasts of Europe and Africa, and this leads up to a statement of his views as to the cause of the Glacial Period. It is pointed out that there are two principal schools of geographical evolution, the one believing that the ocean basins and the position of the chief continental areas retain traces of their primeval structure and have undergone only slight modification, the other, to which the author belongs, believing that land and sea have changed places at various geological periods. The latter view, he considers, is upheld by a consideration of the distribution of geological formations on both Isides of the North Atlantic. A detailed description is then given of the submerged river-valleys occurring off western Europe and Africa and in the Mediterranean as traced from the soundings shown on the charts. These were formed not only by rivers, the greater part of the course of which is visible on land, such as the Loire and the Congo, but also by rivers which rose on land now completely submerged, such as the "Irish Channel River" and the "English Channel English Channel River." They all indicate a former great uplift of land. The Norwegian fjords also are regarded as river-valleys of great geological age. OUR BOOKSHELF. to The Elements of Statistical Method. By 66 The writing of a satisfactory elementary work on such a subject-a work that can be placed in the hands of the junior student with confidence that he will not have to unlearn at a later stage some of the notions that he has gathered—is an exceedingly difficult feat, much more difficult in many respects than the writing of a work for more advanced students, and we cannot say that, in our opinion, Mr. King has altogether succeeded. The style is simple enough, but some matters are very insufficiently explained-probable errors, for example and in other cases, notably in the In the final chapter Prof. Hull gives his explana- chapters dealing with correlation, extensive retion of the cause of the Glacial Period. As shown from a study of the submerged river-valleys, a general elevation of the earth's crust took place all round the North Atlantic, the date of which is concluded to be about the close of the Tertiary Period. This brought about a much colder climate and at the same time a great change in the direction and temperature of the Gulf Stream. When the Antilles were directly connected with the American continent this current could not enter the Caribbean Sea, where at present it gains vision and correction are required. A coefficient "of concurrent deviations" suggested on p. 208 does not fulfil the fundamental condition of becoming equal to zero if the deviations are independent. The student, in dealing with correlation, is repeatedly told to divide deviations by the mean, and the graph of regression obtained when the deviations have been divided by their respective means is termed the "Galton graph." What Sir Francis Galton did was to divide deviations by their respective quartile deviations-not their graphically in that way. The relation of regresmeans—and he obtained the correlation coefficient sion to correlation is never clearly exhibited, and Mr. King's use of the term is not in accordance with general usage. As it at present stands, the book cannot be recommended as a completely trustworthy guide. about 13° Fahrenheit of temperature; hence arose an additional cause for decreased temperature along all the coasts of the North Atlantic. The combined effect of these two factors, viz., the increased elevation of land on both sides of the Atlantic and the decrease of temperature in the Gulf Stream, would be sufficient, the author considers, to call into existence a rigorous glacial climate over the northern parts of America and Europe, which in its turn would affect a great part of the rest of Europe and western Asia, and more or less the entire northern hemisphere. Thus Dr. Hull shows that he belongs to those who regard purely terres-pology, the editorship of the series being assigned trial factors as the cause of the Glacial Period, in contrast to those who explain it on an astronomical basis. The book is useful to all who are interested in physical geography, whether they can agree with Dr. Hull's conclusions or not. Anthropologie Anatomique. Crâne-Face-Tête sur le Vivant. By Dr. Georges Paul-Boncour. Pp. xix +396. (Paris: Octave Doin et Fils, 1912.) Price 5 francs. (Encyclopédie Scientifique.) THE enterprising publishers of the "Encyclopédie Scientifique" have arranged for the issue of a series of forty-eight volumes dealing with anthro to Prof. Papillault, of 1' cole d'Anthropologie, Paris. This volume, by Dr. Georges PaulBoncour, forms the first of the series, and if its successors maintain an equally high standard, the "Bibliothèque d'Anthropologie is destined to become a standard work. Dr. Paul-Boncour's task is limited to a systematic study of the cranium, the facial part of the cranium, and the head of the living; his volume gives an accurate reflection of the methods and conclusions of the French school of anthropologists. The nature of his book is best indicated by a bare recitation of the subject-matter of its chapters. The volume commences with a discussion on the growth and evolution of the skull, and then passes on to a description of its various parts. The succeeding chapters are devoted to the formation of the cranial cavity, to the methods of measurement and estimation of indices and of angles. The mandible and brain cavity are the subject-matter of special chapters. The second part-the more valuable is devoted to the methods employed in registering the racial and individual characters as seen in living peoplethe form of the head, the development of muscles, the colour of the skin, the shape of the eyes, contour of the nose, form of ear, mouth, hair, and chin. Dr. Paul-Boncour's volume is a simple, explicit, and methodical presentment of methods and opinions which have been perfected by the three generations of men who have made Paris the Mecca of anthropologists. Science of the Sea. Edited by Dr. G. Herbert Fowler. Pp. xviii+452. (London: John Murray, 1912.) Price 6s. net. THERE is a large though scattered body of people interested in oceanography or fascinated by marine biology, but prevented from making any advance. by the want of practical direction and assistance: not only explorers and yachtsmen, but officers in the Navy with time on their hands in port or in foreign stations, medical officers on board ship or on coastal stations, and gentlemen who have retired from active service. To all such who wish to learn the methods of oceanographic inquiry, this book will be gladly welcomed, for it brings together instructions that otherwise are hard to find, given with the greatest care, and tested by the practical experience of many lives. The handbook is, in fact, the collective wisdom of the most active members of the Challenger Society, a body that has met quarterly in an unobtrusive fashion in London for some years, and now expresses its interest in oceanographic research by this publication. The book begins with a chapter on meteorology by Dr. Mill and Capt. Wilson Barker, whose names, like those of the succeeding contributors, are guarantees of soundness and fulness of knowledge, and then proceeds to a well-illustrated account of hydrography, the joint work of Prof. H. N. Dickson and Mr. D. J. Matthews, of Plymouth. A very interesting and practically helpful account of tropical shore-collecting and outfit is given by Prof. Stanley Gardiner, whose methods, with a little adaptation, are applicable to similar work in temperate seas. Then follow four chapters on marine biology, including one by Sir John Murray on oceanic deposits and the organisms of the seafloor. Fishing, whaling, and sealing are referred to in a rather summary fashion. Finally, the editor gives valuable counsel on methods of notetaking, whilst yacht-equipment, dredging, trawling, and the preservation of specimens are dealt with in a most helpful manner by the Director of the Marine Biological Association and others. We congratulate the editor, Dr. Fowler, on the manner in which he has correlated and brought together such a valuable elementary compendium, and we can recommend this handbook as a trustworthy and practical guide to travellers, and not less a book of great interest to all biologists. F. W. G. LETTERS TO THE EDITOR. [The Editor does not hold himself responsible for opinions expressed by his correspondents. Neither can he undertake to return, or to correspond with the writers of, rejected manuscripts intended for this or any other part of NATURE. No notice is taken of anonymous communications.] Practical Mathematics. I WAS particularly sorry to be absent from the meetings of the International Mathematical Congress at Cambridge, because an address was expected from me upon the teaching of practical mathematics, and because Sir Wm. White, in his address on the relation of mathematics to engineering practice, referred to practical mathematics in a most contemptuous way. Twenty years ago mathematics continued to be taught in what may be called the orthodox way, a way that succeeded fairly well with students who were fond of abstract reasoning, 3 per cent. of all students, and quite failed with the other 97, per cent. At the British Association discussion of 1901 (verbatim report published by Messrs. Macmillan), most of the great mathematicians and teachers of mathematics spoke or sent remarks in writing. In opening that discussion, I published my proposed Science and Art Department syllabus on practical mathematics. There was essential agreement with my views; there was scarcely one dissentient remark. A committee was formed, and recommended methods of teaching which are now extensively adopted. It is perhaps a pity that I gave such a misleading name as practical mathematics to the reformed methods, but I wanted to differentiate them from the orthodox methods of twenty years ago, and I did not dream that the new methods would be adopted so quickly. They are in use now in all the public schools where natural science is taught; they are in use in all science colleges and in all engineering colleges. In evening schools it used to be that when a class of thirty apprentices was started in elementary mathematics, the attendance dwindled to ten in November, and in May it was usual to find only one or two faithful students. Now, in such schools, there is almost no teaching of the kind we used to call orthodox, but some hundred thousand apprentices study practical mathematics. The class of thirty formed in September remains in good attendance all the winter, and remains an excited and interested class of thirty in May. The new method suits the boy of great mathematical promise, but it is really arranged to give the average boy a love for computation and the power to use mathematical reasoning with pleasure and certainty. It recognises that every boy, every man, already possesses the fundamental notion of the infinitesimal calculus, and that it is quite easy |