A Class of Functional Invariants. By A. R. Forsyth, M.A., F.R.S. Total Eclipse of the Sun observed at Caroline Island, on May 6, 1883. By Captain W. de W. Abney, C.B., R.E., F.R.S. On Evaporation and Dissociation; Part VIII. A Study of the Thermal Properties of Propyl Alcohol. By William Ramsay, Ph.D., F.R.S., and Sydney Young, D.Sc. The Radio-micrometer. By C. V. Boys, F.R.S. The Waves on a Rotating Liquid Spheroid of Finite Ellipticity. By G. H. Bryan, B.A. On the Magnetization of Iron and other Magnetic Metals in very Strong Fields. By J. A. Ewing, B.Sc., F.R.S., and William Low. Some Observations on the Amount of Light reflected and transmitted by certain kinds of Glass. By Sir John Conroy, Bart., M. A. On the Total Solar Eclipse of August 29, 1886. By Captain L. Darwin, R.E., Arthur Schuster, Ph.D., F.R.S., and E. Walter Maunder. Report of the Observations of the Total Solar Eclipse of August 29, 1886, made at the Island of Carriacou. By Rev. S. J. Perry, S.J., F.R.S. On the Determination of the Photometric Intensity of the Coronal Light during the Solar Eclipse of August 28-29, 1886. By Captain W. de W. Abney, C.B., R.E., F.R.S., and T. E. Thorpe, Ph.D., F.R.S. Report of the Observations of the Total Solar Eclipse of August 29, 1886, made at Grenville, in the Island of Grenada. By H. H. Turner, M. A., B.Sc. Revision of the Atomic Weight of Gold. By J. W. Mallett, F.R.S. Magnetic and other Physical Properties of Iron at a High Temperature. By John Hopkinson, M. A., D.Sc., F. R.S. The Diurnal Variation of Terrestrial Magnetism. By Arthur Schuster, F. R.S. With an Appendix by H. Lamb, F.R.S. 1889, SERIES B. With 29 Plates. Price 1 145. CONTENTS: On the Present Position of the Question of the Sources of the Nitrogen of Vegetation, with some New Results and Preliminary Notice of New Lines of Investigation. By Sir J. B. Lawes, Bart., LL.D., F.R.S., and J. H. Gilbert, LL.D., F. K. S. On the Secretion of Saliva, chiefly on the Secretion of Salts in it. By J. N. Langley, M. A., F.R.S., and H. M. Fletcher, B. A. On the Organization of the Fossil Plants of the Coal Measures; Parts XV. and XVI. By William Crawford Williamson, LL.D., F.R.S. On the Electromotive Changes connected with the Beat of the Mammalian Heart, and of the Human Heart in particular. By Augustus D. Waller, M.D. Researches on the Structure, Organization, and Classification of the Fossil Reptilia; VI. On the Anomodont Reptilia and their Allies. By H. G. Seeley, F. R.S. On some Variations of Cardium edule apparently Correlated to the Conditions of Life. By William Bateson, M.A. On the Descending Degenerations which follow Lesions of the Gyrus Marginalis and Gyrus Fornicatus in Monkeys. By E. P. France. With an Introduction by Prof. Schäfer, F.R.S. Sold by HARRISON & SONS, 45 and 46 St. Martin's Lane. Separate Papers from the above on Sale by LIGHT THE DOMINANT FORCE OF THE UNIVERSE. By Lieut.-Colonel W. SEDGWICK, R.. Engineers. Crown 8vo, Cloth, 7s. 6d. An endeavour has been made to work out the whole argument by ewe ment, avoiding all technicalities, and advancing step by step from principles in such a way that the whole statement may be intelligible rate non-scientific reader. POETRY OF THE ANTI-JACOBIN, com- An Edition de Luxe of 250 Copies for England and America, uual and signed, printed on hand-made paper, Crown 4to, Cloth Extra, Guinea nett. Full prospectuses on application. THE LANCASHIRE LIFE OF BISHOP FRASER. By JOHN W. DIGGLE, M.A, Vicar of Mossley PL Liverpool, Hon. Canon of Liverpool, also Edit of Bishop Fan Sermons. FIFTH EDITION. 1 Vol., Demy 8vo, Illastraindika 12s. 6d. "Many important and hitherto unpublished letters enrich a vas casts a flood of light on every phase of Dr. Fraser's career in Liscar This fascinating biography."-Standard. A NEW AND VALUABLE HISTORY OF AMERICA, JUST COMPLETED. AMERICA: FROM THE PREHISTORIC AGE TO THE MIDDLE OF THE PRESENT CENTUAL Narrative and Critical History of America. Edited by JUSTIN WINSOR, Librarian of Harvard University; Corresponding Sony Massachusetts Historical Society. 8 Vols, profusely Illustrated Maps, Views, Portraits, &c., 600 Pages each. Price of the Com; ** Work, Cloth Extra, Gilt, £12 nett. The Athenæum says of Vol. VI. :-"It is as good as any of the pr ing ones, and that is no small praise. The nearer this work reaches itse the greater is our admiration for it as a whole. It is an honour to use and his contributors, and is in all respects worthy of its subject." The book throughout is extremely readable, and there are p in it of deep feeling and rare imaginative insight. The closing epise the story are powerfully told, and the book grows in dramatic intensity nears its final page."-The Speaker. KIT AND KITTY: a Story of West Middle SEX. By R. D. BLACKMORE, Author of "Lorna Doane," "4" THIP Vaughan," "Springhaven," "Cripps the Carrier," &c. EDITION. Three Vols., Crown Svo, Cloth, 314. ed. "Kit and Kitty is a manly book, with a sort of fine, open deli Few or zove's sentiment, thoroughly wholesome and pleasing. have maintained so high a standard of excellence throughout." —. I then ca LONDON: SAMPSON LOW, MARSTON. SEARLE, & RIVINGTON, L491 * St. Dunstan's House, Fetter Lane, Fleet Street, E.C. THURSDAY, MARCH 20, 1890. A NATURALIST IN NORTH CELEBES. A Naturalist in North Celebes. By Sydney J. Hickson, M.A. (Cant.), D.Sc. (Lond.), M.A. (Oxon. Hon. Caus.). With Maps and Illustrations. Pp. 392. (London: John Murray, 1889.) 'HIS book is the outcome of the residence of a THIS specialist for nearly a year upon a small island off the extreme north point of Celebes. Of books of travel there is in these days no lack, and so beaten are the paths along which authors for the most part lead us, that the reader in search of amusement or instruction not infrequently arrives at the index without having met with either. But Dr. Hickson's is not a book of travel: it is a record of a naturalist's life with an almost boundless submarine field for observation close at hand-albeit terrestrially somewhat limited-and when he leaves his coral-girt island, it is to wander in that little-known archipelago which links Celebes to the Philippines, the Sangir, Nanusa, and Talaut groups, whither few but adventurous Dutchmen have penetrated. Of the fourteen chapters, three are devoted to Talisse, the island on which Dr. Hickson conducted his observations. Four are descriptive of his wanderings in the groups just mentioned, and the remainder for the most part treat of the Minahassa district, its natives, and their mythology and customs. Of these, the author tells us in his preface that "the greater part of the ethnological portion of the book is borrowed from the valuable writings to be found in many of the reports of missionary and other societies, and in Dutch periodicals." Dr. Hickson owing his voyage almost entirely to a desire to study the corals of the Malay Archipelago, it is naturally to that part of the book which treats of them that we first turn. No one has ever yet done justice to the wonderful beauties of coral-land, and the author, in common with his predecessors, has failed-as everyone must fail-to convey to the untravelled reader an adequate idea of the appearance of a vigorous reef. Perhaps the very fact of being an authority has lessened his chance of success. The description is nevertheless a good one, and the chapter (vi.) the most important in the book. Dr. Hickson has wisely relegated his technical work to the publications of the various learned societies, but he tells us much of interest. The first sight of a coral reef at close quarters astonished him-specialist as he was :— "I could not help gazing with wonder and admiration on the marvellous sight. . . . I had expected to see a wonderful variety of graceful shapes in the branching madrepores and the fan-like, feather-like alcyonarians, ...but I was not prepared to find such brilliancy and vanety of colour" (p. 15). That vexed and most important question, the growth of coral reefs-a question upon which it was to be hoped that Dr. Hickson might be able, from the length of his stay and his varied opportunities, to enlighten us is left pretty much where it was. We should be able to predict with certainty the direction and the rapidity of VOL. XLI.-No. 1064. growth. As it is now, charts of coral islands and reefs become almost valueless in the course of a few years. But the causes both of growth and erosion are still undetermined. Much, no doubt, depends upon the rapidity of the tides. In strong tide-races no true coral reef is ever formed. "Flowing water, which is neither too swift nor too stagnant, bearing the kind of food necessary for the proper nourishment of the corals," is, as Dr. Hickson justly remarks, a strongly predisposing element to vigorous growth. Yet this is not always the case, neither does the converse always hold good; and we cannot agree entirely with the author when he says, "in deep bays or inlets, where tidal and ocean currents are scarcely felt, there is but little vigour in the reef." The inner harbour of Amboyna displays as rich a "sea garden," perhaps, as any in Malayan seas. Dr. Hickson's daily work on the reefs led him to the certain conclusion that but one true species of Tubipora exists. The size of the tubes and the character of the septa-upon which most of the species are founded-are shown to be utterly without specific value; these differences depending entirely upon the position of the coral on the reefs. The following remarks upon a fact which must have struck most naturalists in tropic seas, but which we do not remember ever to have seen in print before, are worthy of quotation. Talking of sunrise and early morning, he says: "Not only are the birds and insects, which disappear as the sun becomes more powerful, particularly visible at that hour, but it is the time of day above all others when the surface of the sea teems with animal life. I remember well my disappointment when I first got into tropical waters at finding that my surface-net invariably came up almost empty. It was not until I had been at work some time that I made the very simple discovery that in the early morning hours every sweep of the net brings up countless pelagic forms of all sizes and descriptions" (p. 58). The question of the food of corals is yet unsettled; but the author, after careful examination of polypes of various kinds, is inclined to the belief that many of them may be, partially at least, vegetable feeders. No doubt the water with the debris of leaves and fruit and wood, some of in the vicinity of mangrove-swamps is very largely charged which, sinking to the bottom, must enter the mouths of the polypes. Upon the mesenterial filaments of the Alcyonarians, indeed, particles of vegetable fibre are frequently found. It is suggested that the vigorous reefs frequently seen near extensive swamps, may be explained by such an hypothesis. Upon Darwin's theory of the formation of atolls, Dr. Hickson had little opportunity of forming an opinion-little, at least, until he visited the archipelagos already mentioned. He ultimately came to a disbelief in the general subsidence theory, and is not opposed to Mr. Murray's view-that coral reefs can, under favourable circumstances, grow out into deep seawater upon the talus of their own débris. Among many references to birds occurs an account (p. 41) of the existence of the maleo, or brush-turkey, in Ruang Island. Unfortunately, we are not told whether this is Megacephalon maleo, or the smaller Megapodius gilberti. They were most probably the latter; but it would be interesting to know, for the true Megacephalon of Celebes has never, we believe, been recorded as X occurring in the smaller islands. Meyer's story of the whimbrels nesting on trees (probably Numenius uropygialis, Gould, by the way-not N. phæopus) is quoted, but without comment, and it is worthy of remark that no naturalist has as yet confirmed it. Dr. Hickson is not quite accurate in his statement that there are only two Celebean birds which are likewise English. He must often have noticed, in his rambles along shore, not only the common sandpiper, but also the wide-ranging Strepsilas interpres and one or more of the genus Totanus, which are not unfamiliar to us at home. Perhaps one of the best passages in the book is that describing a mangrove-swamp, where the extraordinary conditions of life obtaining within its limits, and the interdependence of that tree and the coral reef, are well illustrated. The scenery of Talisse Island is not particularly beautiful, although the author does not tell us so; but that of the district of Minahassa on the main land is strikingly lovely, and he describes the view of the Tondano Lake as one without an equal. It was unspoilt to him even by the thought of the "heerendienst”—that system of compulsory service which has acted as a red rag to so many Englishmen. Dr. Hickson is not so prejudiced, and is wise enough to recognize-as did Wallace -the enormous advantage which it has conferred upon the people. "I cannot help thinking," he says (p. 208), "that everyone who is really acquainted with the circumstances of these colonies and the character and condition of the people must admit that it is a service both necessary and just. The Dutch Government has brought to the people of Minahassa not only the blessings of peace and security, but also the possibilities of a very considerable civilization and commercial prosperity. . . . In return for all this, it is only just that every able-bodied man should be compelled to lend a hand in maintaining this happy condition of affairs. In a land where the necessities of life are so easily obtained, . . . it would be impossible for the Government to obtain a sufficient number of them to labour on the roads at a reasonable wage." The consequence is that they would be neglected. The heerendienst, then, as Dr. Hickson shows, is the only system possible, without overburdening the Exchequer, or increasing the taxation beyond the endurance of the people. We have not space to dwell upon the description of the Sangir Islands, or on the mythology and customs of the natives of Minahassa, which Dr. Hickson has done well to put within the grasp of those who are unacquainted with the Dutch language. Among the folk-lore it is interesting to notice (p. 241) the story of Lumimuüt's impregnation by the west wind-a story which, if we mistake not, is almost identical with one of Egyptian source. The "swan-maiden" tale-which, perhaps, has as wide a distribution over the surface of the globe as any other again occurs in Celebes. Enough has been said to show that "a naturalist in North Celebes" had a varied interest in his surroundings, which he has contrived to communicate to his readers with success. A little more care, perhaps, would have purged the volume of several misprints, and one or two instances of involved diction. The woodcuts with which the book is furnished are well enough. We wish that anything could be said in UR fears lest this "History of the Theory of ElastiO city" should, like Thomson and Tait's "Natural Philosophy," remain a magnificent mathematical torso have been agreeably falsified by the early appearance of this instalment of the second volume. It is devoted entirely to the work of Saint-Venant, the distinguished French mathematical engineer. Saint-Venant is one of the rare examples of a writer who is equally popular with the mere mathematician and with the practical engineer. To quote from the author's preface to this part of the "History of Elasticity," " we live in an age when the physicist awaits with not unreasonable excitement for greater revelations than even those of the past two years about the ether and its atomic offspring; but we live also in an age when the engineer is making huge practical experiments in elasticity, and when true theory is becoming an absolute necessity for him, if his experiments are to be of practical as well as of theoretical value." This is the opinion of the theorist; but the engineer points to his work as magnificent experiments on a gigantic scale, to which he invites the theorist to an inspection, for him to deduce his theoretical laws. So far as pure theory is concerned, the engineer trusts only to Hooke's law, and Euler's theory of the beam, which neglects the warping of the cross-sections. But Hooke's law is shown by the testing-machine to be only a working hypothesis within very narrow limits of extension and compression, after which the baffling phe nomena of plasticity make their appearance, and destroy all the simple mathematical harmony; while as to Euler's theory of the flexure of the beam, the editor, Prof. Pearson, is at present engaged on the mathematical discussion of the permissible limits of the application of the ordinary theory, and, so far, the result of his investigations (in the Quarterly Journal of Mathematics) is such as to strike dismay in the heart of the practical man who would be willing to apply his conclusions. The purely mathematical theory of Elasticity is, at the present moment, in a very curious condition, for a subject in the exact science par excellence. Not only are elasticians divided into opposite camps of multi-constancy and rari-constancy, but we find a war of opinion raging among the most recent investigators-Lord Rayleigh, Chree. Love, Basset, and others. All are compelled to violate apparently the most fundamental rule of mathematical approximation; and, in considering the elasticity of a curved plate, to begin by neglecting the terms depending on the stretching of the material, which involve the first power of the thickness of the plate, in comparison with the terms depending on the bending, involving the cube of the thickness; thus apparently neglecting the first power compared with the third power of small quantities. But, if we take a thin sheet of brass or iron in our hands, we shall find it quite easy to bend, but apparently impossible to stretch or shear in its own plane, showing that the stretching stresses may be considered as nonexistent, by reason of requiring such large forces to produce them. Before pure mathematical treatment can make much progress in Elasticity, much more experimental demonstration is required of the behaviour of pieces of metal of mathematical form under given applied forces; and such experiments can be carried out in testing-machines, now forming an indispensable part of a physical laboratory. Saint-Venant's memoir on torsion, analysed in Section I., is familiar to us through its incorporation by Thomson and Tait, and shows that Saint-Venant carried out, with the comparatively crude methods at his disposal, valuable experiments, from which much theoretical deduction has been made; the analogues of the mathematical analysis in the problem of the torsion of the cylindrical beam of given cross section, and of the flow of viscous liquid through a pipe of the same section, or of the rotational motion of a frictionless liquid filling the cylinder being very striking. Prof. Pearson introduces great elegance and interest into the series which arise by a free use of the notation of hyperbolic functions, and we think there is still some interesting work for pure mathematicians in the identification of those series which are expressible by elliptic functions. But it certainly looks curious to find in § [287] the old familiar polar co-ordinates treated as mere conjugate functions, without reference to their geometrical interpretation. Section II. is occupied with the analysis of SaintVenant's memoirs of 1854 to 1864, in which he attacks such questions in practical elasticity as the longitudinal impact of bars, illustrated by very ingenious graphic diagrams, and also the conditions of stress of a cylindrical shell, in equilibrium under given applied internal and external pressures. This is the problem required in the scientific design of modern built-up artillery; and it is noticeable that Saint-Venant's solution differs materially from Lame's, subsequently popularized by Rankine, the theory employed, as far as it will go, by scientific gundesigners all over the world. The researches in technical Elasticity of Section III. arose in the annotations of Navier's "Leçons sur la Résistance des Corps solides"; the mantle of Navier descended on the shoulders of Saint-Venant, and ultimately the notes of Saint-Venant overwhelmed the original text of his master Navier; and, according to Section IV., Saint-Venant has practically done the same thing with Clebsch's "Elasticität.” Being the mathematical referee for all the difficult theoretical problems arising with the extensive use of the new materials iron and steel in architecture and engineering, Saint-Venant was provided with a number of useful problems on which to exercise his ingenuity; such as the impact of bars, the flexure of beams due to a falling weight or a travelling load, the critically dangerous speeds of fly-wheels and piston-rods, and so on; all problems hitherto solved by practical rule of thumb, the practical constructor encountering and opposing the difficulties without knowing why and how they arose. Saint-Venant's investigations urgently need extension and application to the critically dangerous conditions which can arise in the stresses in artillery, when the dynamical phenomena are analysed, due to the sudden and periodic application of the powder pressure, and to the wave-like propagation and reflection of the stresses in the material. At present, we can only investigate the theoretical strain set up in the material of the gun by a steady hydrostatic pressure equal to the maximum pressure of the powder, employing Lamé's formulas, and then employ an arbitrary factor of safety, say 10, in the design of the gun, to provide against the contingencies of the dynamical phenomena we have not yet learnt how to discuss. In the old times, before the Cambridge Mathematical Tripos was reduced to its present meagre curriculum, the examiner would have found the present volume very useful in suggesting good ideas, capable of testing reasonably the mathematical power of the candidates; at present, the chief class to profit by the present work are the practical constructors, who will learn where to look for the useful information on the narrow technical point which concerns them. Prof. Pearson has brought his onerous task one step nearer to completion in this interesting volume, a monument of painstaking energy and enthusiasm. GLOBES. A. G. GREENHILL. Hues's Treatise on the Globes (1592). Edited by Clements R. Markham, C.B., F.R.S. (London: Reprinted by the Hakluyt Society, 1889.) THE Hakluyt Society has for its object the reprinting of rare or unpublished voyages and travels, and few are worthier of this honour than the "Tractatus de Globis " of Robert Hues. The author of this work was an intimate friend of Sir Walter Raleigh, and combined book-learning with practical knowledge gained by joining in some of the voyages to the New World with navigators whose names have made the sixteenth century famous. He strongly urged that his countrymen would have still further surpassed their Spanish and Portuguese rivals if they had "but taken along with them a very reasonable competency and skill in geometry and astronomy." In those days logarithms were unknown, and the solution of the problems of nautical astronomy required advanced mathematical knowledge. It was hoped that this difficulty would be overcome by the extended use of globes, which at once reduces these complex questions to approximate solution by inspection. After the construction of the Molyneux globes, Hues's treatise came into very general use, and no doubt played an important part in the explorations of the succeeding century. It seems strange in these days, when a globe can be purchased for a few shillings, to read that only three centuries ago the construction of globes entailed such great expense that the liberal patronage of a merchant |