摘要:

To form and to strengthen character; to 1 train tastes which will dignify leisure; to awaken and guide intelligence, especially on its practical side: these are the three ends which the Consultative Committee of the Board of Education had in mind when framing the recommendations which have been embodied in its Report on the Education of the Adolescent, and, even though we may have some difficulty in discovering the exact dividing line between the qualities of the second and third, we must admit that they are ends which, if attained, would make formal education almost as vital to human life and activity as nutrition and reproduction. There are, of course, many forces which operate against the attainment of such ends, and not the least is the attitude of mind of the very committees which make such valuable recommendations. Let there be no mistake: if, as we shall attempt to show later, the present Committee has not been infallible, there can nevertheless be no doubt that it has faced its problems with unusual breadth and clarity of vision. It has faced boldly-whether the revision and extension of school nomenclature it suggests receive approval or not-the inevitability of a regrading of education, and it has not lacked the courage to recommend the raising of the school leaving age. It has left no avenue unexplored, and it has neglected no statistical detail in order that, so far as it could see them, no factors of the present system should be avoided in its argument. Not forgetting that " a community must solve its . . . problems in accordance with its own traditions and customs," the Committee has carefully examined the history which has brought these factors into being, and has lucidly set forth the lines of advance which it believes will lead to a system capable of securing for its pupils the benefits we have described. Nor has it shirked the issue of demonstrating how its recommendations may be made administratively possible.These points, in themselves, are perhaps sufficient to demonstrate with what sense of responsibility the Committee regarded terms of reference which not only requested attention to the organisation, objective, and curriculum of courses of study for children (other than those attending secondary schools) who will remain in full-time school attendance up to the age of fifteen, but also that regard should be had to their probable future occupations I Board of Edulcation. Report of the Consultative Committee on the Education of the Adolescent. -Pp. xxiv + 339. (London: I.M. Stationery Office, 1926.) Paper, 2s. net; cloth, 3s. net. Reading that, the technical teacher might well begin to congratulate himself that, at last, the liberal quality, as well as the importance of his work, was being recognised; and he would be strengthened in his view when he read, further, a recommendation which begins: " A humane and liberal education is not one given through books alone, but one which brings children into contact with the larger interests of mankind." If he read still further, however, he would discover that the Committee is discussing the proposed ' Modern ' (at present 'Central') Schools, and that when it realises whither the argument may lead, seems to become suddenly fearful and is careful to point out that it is not suggesting any wide extension of Junior Technical Schools, but that the ' modern' school should develop with a 'realistic' or 'practical' bias and should not aim " at giving a technical or vocational education." He would see that the Committee's attitude towards technical education is one which fits but ill with the philosophical statements which preceded his search. A little puzzled, he would turn to the Committee's definition of this word ' bias,' and find his dilemma still further increased. Finally, he would lose the last vestige of his optimism when he discovered the Committee's view that a foreign language is regarded as necessary in the modern school, but its necessity in the Junior Technical Schools even though its lack may be a barrier against matriculation and entry into the learned institutions-is set out in very guarded terms. He will not, therefore, be very much to blame if he thinks the work of technical education is still but little understood, and that the ancient and arid arguments between the values of ' arts ' and 'sciences,' and between 'pure' and 'applied' science are not yet at an end. A crumb of comfort will fall to him, however, when he reads that, on suggested examination boards, " Technological teachers might be co-opted."If, in its view and knowledge of the work of technical schools, the Committee has not been infallible, it is beyond doubt that it has been very largely influenced by the inevitable trend towards the linking up of education and industry. It has not failed to observe that the modern development of industry has resulted in a loss of craftsmanship and an increase in leisure, due to the lessening hours of labour, and it has therefore rightly regarded the school as an instrument which can do much to counteract the loss of craftsmanship and to secure that leisure may be wisely used. In this connexion it has laid some stress upon handwork, and, in addition, to recommending that a sufficient number of teachers must have the craftsman's interest and outlook; it has given evidence of its recognition of another important question by its suggestion that girls as well as boys should learn something of the use of tools, and should be allowed to take a short course in wood and metal work. There is not, perhaps, much that is new in the Committee's suggestions on the teaching of science. The interdependence of the various subjects is clearly indicated. Not only is the science teacher to keep closely in touch with the teachers of drawing and mathematics, but also " simple apparatus might be made by pupils in wood and metal lessons." In the case of girls, the science courses of the Modern Schools should, in their later stages, have a biological trend; and the work should not, as is frequently the case, be confined to botany. The reasons given for this recommendation show that the Committee has taken care that the liberal qualities of science teaching shall be thoroughly understood, and that it shall not aim at the assimilation of unrelated facts. " The study of simple forms of animal life can . . . be made an admirable means of widening and disciplining the pupils' sympathies " and will increase happiness and efficiency. In the same way, for boys and girls, instruction in biology and elementary physiology " might well provide the basis for a right attitude to many social problems." To the initiated these suggestions may form part of an accepted philosophical attitude towards education-especially on its scientific side-which is almost a sine qua non of a rapidly developing society. For our part we welcome them, since we do not lack evidence that words and actions are often poles apart, and we realise that there cannot be too much examination and repetition of fundamentals.If post-primary education is to be a unity in the full sense of that word, we may be pardoned if we refer to a subject sometimes (wrongly) regarded as outside our province. In dealing with the teaching We willingly run the risk of being told that we are not aware of the correct place of such teaching. For the moment we regard it as sufficient that the point be made, and, while waiting for the later pronouncements upon such an important theme, we may leave it quite safely in the hands of the teachers of science. I Board of Edulcation. Report of the Consultative Committee on the Education of the Adolescent. -Pp. xxiv + 339. (London: I.M. Stationery Office, 1926.) Paper, 2s. net; cloth, 3s. net.

ISSN:0028-0836    

DOI:10.1038/119185a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THIS imposing volume is known in Germany and Austria as the " Dreimannerbuch." It is the first of a trio of books intended to deal exhaustively with modern representatives of those ' occult sciences 'which have never ceased to occupy a certain type of mind since the days of Paracelsus. The increasing habit of civilised humanity to submit all such 'hidden' sources of knowledge to examination by modern scientific methods has driven their advocates and devotees to adopt at least an apparently up-to-date terminology. Thus we do not hear much about the Secret Rose, the Elixir of Life, or the Fifth Essence. But we are told all the more about Psychophysical Energy, Metapsychics, Rigid Rays, Telekinesis, and Ectoplasia-imposing words which to many minds convey an irresistible suggestion of reality.It would of course be impossible to deal in one book with the vast volume of occult literature, nor do the ' three men ' make any attempt to do so. But they do pass in review what may be called the serious treatments of the subject, and the sporadic attempts to apply some scientific method to the study of alleged phenomena which seem to contradict well-known physical and biological laws. Of the three authors of this book, Count von Klinckowstroem deals with the " Confessions of a Medium " as well as classical mediums like D. D. Home, Florence Cook, Slade, Guzik, and Mrs. Gilbert. Dr. Rosenbusch studies Eusapia Paladino, Stanislava Tomezyk, and Kathleen Goligher, while Dr. von Gulat-Wellenburg examines the claims of Marthe B6raud ('Eva C.'), Franck Kluski, Willy Schneider, Nielsen, and Laszlo.It mayseem a deplorable waste of time and energy to devote five hundred pages of close print to the criticism of alleged phenomena which have been almost unanimously rejected by the scientific world. But it is necessary to remember that we are here dealing with alleged happenings which, if authenticated, would necessarily change our whole outlook on the possibilities of life and even of nonliving matter. Even in their unproven state these alleged observations are exerting a very wide influence on great masses of contemporary thought and feeling. To millions they form the basis of a new religion purporting to have a sound scientific basis. One cannot envy the fate of the few leaders of science whose names are perennially quoted as supporting and sanctioning spiritualist practices. The name most widely exploited in this connexion is that of the late Sir William Crookes, whose few experiments, undertaken without appropriate training and then abandoned, have formed a peerless model for all later investigators and imitators. The truth appears to be that these ' supernormal' phenomena bring us face to face, not so much with a higher world of spirit as with an underworld of human credulity, based upon an irresistible appetite for the marvellous. This appetite or need has always existed; and it has always rebelled against the established order of things. It has always postulated the existence of beings superior to it, whether angels or jinns or the spirits of the dead. Who can wonder that men trained in scientific methods have sometimes shown a similar weakness ! Physicists show this tendency perhaps more than others. But that may be due to the fact that their researches are the most fundamental as regards the structure of the universe. They work on the very frontier of the unknown and their recent discoveries are so marvellous that a miracle more or less does not seem to signify.The modern attempt to erect occultism into a science was supported, if not initiated, by Alexander Aksakof, whose " Animism and Spiritism " advocated the. view that spiritistic phenomena were not due to disembodied intelligences but to unexplained powers of the human organism itself. It was he who coined the word 'telekinesis' for movement without contact, and one cannot help wondering how many conjuring tricks, clever or otherwise, have since been dignified by that beautifully fashioned Greek word. It was Dr. Ochorowick who invented 'ectoplasy,' though it did not become popular until F. W. H. Myers defined it in his work on " Human Personality and its Survival of Bodily Death." He called it " the power of forming outside some special organism a collection or reservoir of vital force or of vitalised matter which may or may not be visible or tangible but which operates in like fashion as the visible and tangible body from whence it is drawn." Many attempts have been made to investigate this mysterious 'vitalised matter' and to define its properties. If we were to take the current spiritualist view, ectoplasy, or rather 'ectoplasm,' would be the substratum of all 'materialisations,' even of full figures like Crookes's Katie King, plus her calico dress. It would also constitute the 'rigid rays ' emanating from the fingers of Mlle. Tomezyk, the 'psychic rods ' of the Goligher circle, and the plastic structures described by Dr. v. Schrenck-Notzing. The latter were supposed to consist of amorphous material capable of assuming any form or appearance suggested by the medium's subconscious mentality. Thus they sometimes showed the structure of half-formed faces in plaster -of -Paris, which were ascribed to the frequent visits of the medium to a sculpture studio.According to Schrenck-Notzing the ectoplastic structures are very sensitive to illumination and to touch. 'Katie King,' in Crookes's charmed circle, could cut off strips of her dress, and materialise them permanently enough to be examined in daylight. But ordinarily the material is fugitive in light, and contact is not allowed for fear of injuring the medium. Here again it is difficult to arrive at any sort of consistency. Dr. Crawford was allowed to touch a 'psychic rod.' It felt like a stockinged foot, with toes complete, but the medium was neither hurt nor injured by the touch. Also, did riot v. Schrenck-Notzing himself take a kinemato graph picture of a materialisation without inflicting any injury ?A biologist inclined to credit the existence of ectoplasm endeavoured some time ago to form some intelligible conception of it by supposing it to partake of the nature of pseudopods put out by unicellular organisms. But this would scarcely account for Katie King's obviously woven calico. The late Dr. Crawford's speculations concerning 'X' and 'Y' matter building up 'psychic rods' capable of lifting tables and adhering to carmine and other pigments cannot be taken seriously, in view of the total absence of scientific control of the Goligher circle. Nobody has as yet put forward a description of 'ectoplasm' which will cover the various forms of its alleged occurrence or permit of any consistent theory as to its properties. Even the assertion that it emanates from the epithelium of any natural orifice of the organism fails to cover cases where it is alleged to emanate from the fingers. The analysis of a fragment of the substance said to have been isolated by Dr. v. SchrenckNotzing showed nothing but epidermis such as might have been peeled off a human heel. The authors of the " Dreimiinnerbuch " must be congratulated on the minute and serious analysis of all 'supernormal' phenomena which have been vouched for by persons of any scientific standing. Their criticism is objective and temperate, and in allcases where a normal explanation is difficult or impossible they frankly admit its being so. One is therefore inclined to give all the more weight to their main conclusion, which is that the scientific proof of the reality of physical mediumistic phenomena has never yet been furnished, all the alleged phenomena being capable of a normal explanation based upon deception or inadequate observation. The only cases which they are inclined to leave in doubt are certain reports concerning D. D. Home and a few experiments with Eusapia Paladino. But even these are now of little value owing to the impossibility of repetition. That the phenomena in question are rare and elusive does not in itself deprive them of scientific interest. But it is becoming increasingly clear that any hope of their substantiation depends upon the provision of competent observers. The qualifications of such observers must be very high, much higher than in the case of ordinary physical and biological investigations. Not only must the psychic researcher be acquainted with all the abnormalities of vision in a feeble light and under prolonged strain, but he must also be versed in the numberless possibilities of deliberate deception and trickery. The ordinary physicist or biologist is quite incapable, as a rule, of explaining a clever conjuring trick performed in a bright light. Yet he will sometimes assert that all possibility of fraud was excluded in circumstances which would make a conjurer smile.No new observations can in future be taken seriously unless the observer shows a close acquaintance with the sources of error involved in these investigations. In this respect the " Dreimannerbuch " furnishes a valuable test of knowledge. Considering that the English speaking world is more obsessed by spiritualism than the rest of civilised mankind, an English translation of this book would fill an important place by the side of Myers and Podmore.

ISSN:0028-0836    

DOI:10.1038/119187a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THE progress of physics during the last few 1 decades has been truly remarkable, and it is with a feeling akin to hopelessness that the present-day physicist vainly attempts to keep abreast of the times. As the science has developed, specialisation has become more and more necessary, and it is to this intensive specialisation that physics owes its present vastness. In such circumstances, the need for an up-to-date " Handbook of Physics " for purposes of reference has become increasingly urgent, and it was to be expected that sooner or later such a work would be forthcoming. In English, the " Dictionary of Applied Physics " serves a useful purpose in enabling physicists to have easy access to recent developments in the divers branches of their subject, and in German, apart from several excellent handbooks on special branches, Winkelmann's " Handbuch " has done valuable service, though it is now somewhat outof-date. The deficiency is now being rectified, and there are at present in course of publication two distinct 'handbooks' of physics. One of these, the "Handbook of Experimental Physics," is being edited by Wien and Harms. Its aim is to give a detailed presentation of modern physics and geophysics from the experimental viewpoint, and to introduce only that minimum amount of theory necessary for the intelligibility of the actual facts, in view of the tendency of modern theory to age as fresh experimental material accumulates. For obvious reasons of uniformity, the number of contributors to the work has been kept as low as is consistent with an authoritative treatment of the various branches of the subject. Geiger and Scheel are primarily responsible for the editing of the other " Handbook of Physics." The number of contributors is larger than in the work of Wien and Harms, and the scope of the 'handbook' is more comprehensive, for it aims at giving a complete survey of the current position of theoretical as well as of experimental physics.The list of distinguished scientific workers contributing to these two 'handbooks' is a guarantee of the excellence of the finished products. Nevertheless, one cannot suppress a feeling of regret at the publication simultaneously of two monumental works, the expressed aims of which are so similar. Surely one such work would have sufficed to fill the gap in current literature. Each 'handbook' is to comprise some twenty or more volumes, at a total cost of anything from forty to sixty pounds. Few private individuals can afford such an outlay for a comprehensive work on physics, and whereas most scientific libraries will endeavour to procure one or other of the handbooks, it is equally certain that they will be unable to procure both. The volumes can, however, be obtained separately. (1) Vol. 2 of the Wien-Harms ' handbook' is entitled " The Mechanics of Particles and of Rigid Bodies." This is probably the most difficult of the various branches to bring within the scope of a handbook of experimental physics, for in it experiment plays a much less predominant part than in other branches of physics, and it has reached such a state of development that it has fewer fundamental advances to record than have other departments of the subject. For this reason, and we believe wisely, Prof. Haas has departed from tb e acknowledged form of 'handbooks,' usually so full of detailed references to the literature, and the result is very pleasing.The book is divided into three parts, the first dealing with the motion of a particle, the second with the mechanics of a rigid body, and the third being devoted to the mathematical treatment of the mechanics of rigid bodies. The first two parts are comprehensive, but essentially elementary in their mode of treatment, and only the most important results of theory are presented, in so far as they are of importance in experimental physics. The experimental foundations of the theory and the comparison of the results of theory and experiment are discussed, and particular attention is given to mechanical problems which are important in the physics of measurement. The mathematical development of the subject has been intentionally relegated to the third part of the volume, so as to simplify the task of the less mathematical reader. In accuracy of thought, logical development, and clearness of expression, the author is a master, and it would be difficult to imagine a more admirable treatment of the fundamental conceptions of kinematics than we find in the opening chapter of the book. Equally good are the chapters on pendular motion, processes of motion on the rotating earth, celestial mechanics, and gyroscopic motion, to mention but a few.Free use of vector notation is made in the third and essentially mathematical part of the book. As the various results are derived, the appropriate references to the earlier non-mathematical sections of the text are given. This last section of the volume is perhaps the most valuable of all, for the treatment, though brief, is masterful, and contains all the essential steps in the development of the numerous results. The book is attractively produced, and contains more than two hundred illustrations, carefully done, which add greatly to its clearness. The volume concludes with a list of references to recent literature on the experimental aspects of such topics as general and terrestrial gravitation, gyroscopic phenomena, and friction between solid bodies.We have learned from experience to expect something good from Prof. Haas, and once again we are not disappointed. (2) Vol. 1 of the Geiger-Scheel 'handbook' is devoted to the history of physics and to the technique of lecture experiments. It comprises four chapters-rather an odd term, in view of the fact that the second and third chapters together occupy only twenty-eight of the four hundred pages in the book.The history of physics (Chap. i.) has been admirably written by an acknowledged authority on the subject, Prof. Hoppe of Gbttingen. In one hundred and eighty pages we are provided with a fascinating account of the progress of physical science from Babylonian times up to the year 1895. The first section deals with the contributions of the Babylonians, the Egyptians, the Greeks, and the Arabians, and concludes with a review of scientific advance in Christian Europe as far as the year 1600. At this point was initiated a period of sound progress, when men like Kepler and Newton placed the subject on an exact basis, and freed it from methods of idle speculation which all too frequently characterised the work of those who preceded them. The second section of the chapter is concerned with this period of intensive growth, and brings us to the year 1842. In the third and final section, which ends with the year 1895, we pass in review the work of Kelvin, Helmholtz, Maxwell, and their contemporaries, and are led from classical physics to the fringe of modern atomic physics, for the chapter concludes with the discovery of radium and polonium. Detailed references are to be found on almost every page. This interesting account of the development of physics through the ages arouses feelings of regret that more time is not devoted, in academic courses, to the history of physics. Text-book physics often tends to give us a wrong sense of perspective in the development of the subject, for it has frequently happened that great advances have been stimulated by the use of hypotheses accepted at the time, but later shown to be untenable. Prof. Hoppe has endeavoured to give a balanced treatment of the growth of physical knowledge, and to place the historical evidence in its right perspective; the result makes informative and instructive reading. Prof. Scheel contributes a brief but interesting account (Chap. ii.) of the development of the research literature of physics, commencing with the Philosophical Transactions of the Royal Society, which first appeared in 1665, and ending with the " International Critical Tables " of the National Academy of Science and the National Research Council, the first volume of which appeared in 1926. In Chap. iii., Prof. Timerding gives a critical account of the teaching of physics in elementary and in high schools. Although his remarks have particular reference to German conditions, many interesting and generally applicable aspects of the question are discussed. Teaching and research in the universities are also dealt with, and an account is given of the establishment and development of scientific societies and research institutes, and of research publications.The importance of experimental lecture demon. strations in university courses of physics has long been recognised, and although the main lines of experimentation are more or less fixed, each department of physics has its own little specialities. University teachers are constantly on the look out for new or modified experiments for lecture courses, and the editors of this 'handbook' have wisely included a section (Chap. iv.) on the technique of lectures, by Drs. Mecke and Lambertz, both of the University of Bonn. Many hundreds of representative lecture experiments on all branches of physics are described, numerous tables of data are given, and the text is copiously illustrated by excellent diagrams, many of which can be obtained from Dr. Mecke in the form of lantern slides. This collection of lecture experiments well repays careful study, and should prove invaluable to university lecturers in physics. The volume under review is nicely printed on good paper, and is remarkably free from misprints. On p. 235, Fig. 21 has been erroneously inverted, and on p. 268 the melting point of mercury is given as 390 C.!

ISSN:0028-0836    

DOI:10.1038/119189a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

"On a far-looking tower I stood to watch, And three tribes I beheld, of war-bands three." THE prologue of this second volume on the TIferns, opening as it does with this apt quotation from Way's translation of Euripides' " Suppliants," serves well to define the author's position in dealing with his theme. For having in his first volume built for himself a basis of morphological criteria, drawn from the entire range of fern life, he now proceeds to use it as a point of vantage from which to view the group as a whole. As the armies in the Greek play were seen to be formed in three distinct columns, each moving independently, so also the author sees three main phyla of ferns progressing from geological time in an evolutionary march, at first distinct and mainly divergent, but later converging in character in the more recent stages of phyletic advance. As in the battle graphically described in the play, the several columns finally merged in an inextricable mel6e, so in the later phases of fern evolution does the writer find the advanced members of his group, and his task of complete segregation of the several phyla of descent, according to their detailed features, grows in difficulty.The broad basis of comparison which Prof. Bower has raised in his first volume, with the view of phyletic seriation of the ferns, is skilfully built on the values which he assigns to morphological features, each of which he has sought to weigh truly. The external morphology of the shoot, the internal constitution of the plant body as indicated by segmentation, the architecture and venation of the leaf, the vascular system, the dermal appendages, the position and structure of the sorus, the indusial protections, the characters of the sporangium and of the spores, the spore-output, the morphology of the prothallus, and the embryology of the sporophyte, have all fallen under his critical judgment during his lifelong and intensive study. Each he has examined critically in the ferns at large, and his views have not passed unchecked by the fossil records. As lhe analysis has proceeded the conclusions have become more acceptable that the simple shoot, radial in construction, and commonly unbranched, is primitive, while the prone, dorsiventral, and unequally branched shoot is almost undoubtedly derivative. In relatively primitive ferns there are several initial cells in the apices of stem, leaf, root, and sporangium, while in later derivative types there is usually a single initial cell in the apices of these organs. The primitive forms of leaf are characterised by a dichotamised distal region, sometimes with basal stipular growths, and by leafsegments which may be all separate, and each provided with a single vein. The primitive venation is open with free endings. In advanced ferns the leaf may be webbed, the venation reticulate, and the lower pinnaarranged monopodially. The primitive axis is protostelic, the more advanced solenostelic, dictyostelic, polycyclic, or marked by further complications. Dermal appendages in the form of simple hairs constitute a primitive feature, while branched hairs, and in particular flattened scales, are held to be indicative of advance from simple hairs themselves. The marginal position of the sorus, more frequent in early than in late fern types, has passed in several distinct phyletic series into the superficial, as the area of the leafblade increased. The individuality of the sorus has also been lost in many sequences by fissions or by fusions, or the sori have been obliterated in time by spreading of the sporangia generally over the leaf-surface. The most important variations are, however, those of constitution of the sorus, three types of which have been distinguished, namely, the simple, gradate, and mixed. The first is characteristic of Palkeozoic ferns, though it survives to the present day. The last is to-day prevalent but is absent in Palaeozoic ferns. The gradate sorus is an intermediate type in many, but not all, phyletic lines.There is no indusial protection in Paloeozoic ferns, nor is such found in certain modern advanced types. But between such extremes protection by various means is provided notably by different types of indusium. The indusiate sorus is thus considered a later and derivative type, while on the other hand there is good evidence that the modern non-indusiate state has often resulted from the abortion of an indusium previously present. In the progression from Palaeozoic to modern times the sporangium shows consistent reduction in size, with increasing specialisation of the mechanism of spore dispersal, while the sporangial form, length of stalk, and the position of the annulus and the stomium vary likewise in close relation to the constitution of the sorus. A gradual diminution of the spore-number accompanies the reduction and specialisation of the sporangium from geological time onwards. There is little to be gleaned for phyletic purposes from the vegetative features of the prothallus, though a surer basis for comparison seems to be provided by the sexual organs, and in particular by the antheridia, which are not only deeply sunk in the prothallus of the primitive ferns, but are also there massive, while in the more advanced types they project and are relatively delicate. As to the embryology of the ferns, it is held that the primitive embryo was probably a spindle-like structure with suspensor and shoot, while the root is an accessory organ of later development. The presence or absence of a suspensor is regarded from the phyletic viewpoint as the most important comparative feature relating to the fern embryo. With the field of comparison thus widened the author proceeds to the detailed consideration of certain families which are held to be the most ancient among known ferns. These are the Ccenopteridaceae and Osmundacece, which have had undoubted Palheozoic existence. With them are closely grouped for comparative reasons the Marattiaceoe and Ophioglossacew, as they also are Eusporangiate ferns.The remainder of the ferns, though prefigured in some measure by fossils of the Paleozoic period, first began to assume their ordinary characters in the Mesozoic period or later. Their relationship is clearly with two relatively primitive families, namely, the Schiziace.T and the Gleicheniacem, both of which became firmly established in early Jurassic times. The former bears its sori on the margins of the leaves, the latter produces them superficially. With their allies they constitute two consistently defined series, the Marginales and the Superficiales, and are regarded as having not improbably originated from some common earlier source. To the discussion of these fascinating and primitive families this beautiful book is mainly devoted. With consummate skill in presentation of fact and argument, and with a wealth of illustration to illumine the written page, the author carries the reader through the intricacies of form and structure which the ferns display. It is only when the closing chapters are reached and the general review of the primitive ferns as a whole has been read, that a full appreciation is gained of the power of the argument which has guided the author throughout the arduous task of phyletic grouping. The consideration of the more advanced series of ferns is delayed to a later volume, but to all who read this book must come a growing desire for the production at an early date of the remainder of this fascinating narrative of the march of evolution.

ISSN:0028-0836    

DOI:10.1038/119191a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

SYLVICULTURAL research is becoming more and more dependent on observations made in permanent sample plots. These plots are marked out in the forest, treated according to the desired experimental methods, and the volume of timber standing in them is periodically measured. The value of such observations is entirely dependent on the accuracy with which the volume of standing crops can be measured, and even small errors in the measurement of any plot may lead to very false results. Thus if the volume of a plot increases in five years by 20 per cent., an error of + 3 per cent. in the first measurement and -3 per cent. in the second may reduce the increment, as measured, to about 13 per cent. Fair accuracy in measurement can be assured if a large number of sample trees can be felled for detailed scaling, but the felling of numerous sample trees is generally sufficient to upset the sylvicultural experiment in hand. In order to obviate these difficulties, nearly every forest research station in Europe has designed its own method of measuring standing timber, and it is claimed that many of these methods give very considerable accuracy. In the memoir under review, Mr. Chaturvedi has collected together all available records of these methods, and by personal visits to many of the continental research stations he has equipped himself with the latest relevant information. He has subjected the various methods to mathematical analysis, and has applied most of them to the measurement of certain plots in which all the trees were felled to allow of accurate volume determination, by which means he has obtained useful empirical evidence as to their relative reliability.Mr. Chaturvedi also propounds a new method which aims at combining the good points of several other systems. This method avoids felling any excessive number of trees, and is well worth testing carefully in the field.

ISSN:0028-0836    

DOI:10.1038/119192a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

Six years have elapsed since the publication of the fourth edition of these invaluable tables, and it is significant of the change in scientific outlook that the first page of the book is now devoted to atomic numbers and the last to a new table of isotopes. In the list of elements in the order of atomic numbers, three numbers only, 61, 85, and 87, are still unrepresented; the first of these gaps will now be filled by the new element illinium, the isolation of which was reported in NATURE of June 5, 1926, p. 792. New matter has been added on the mechanical equivalent of heat, a subject which Prof. Laby has personally investigated, and the weighted mean of the determinations of Joule's equivalent made since 1880 is given as 4-182 x 107 ergs per 20° calorie on the scale of the hydrogen thermometer. The reviewer turned eagerly to the value assigned to Planck's constant, h, only to find that the authors have made no attempt to discriminate between the various experimental values quoted. Even the critical discussions by Ladenburg and by Birge are not referred to. The true value is probably very near to Planck's original estimate, h =6-55 X 10-27 erg sec. The same cautious attitude is adopted in the value quoted for the fundamental electron charge, which is given as e = 4-77 x 10 -10 e.s.u., with a reference to Millikan, July 1917. It may be suggested that in future editions more attention should be paid to spectroscopic constants-even Rydberg's constant does not appear to be mentioned-and other important constants associated with the quantum theory. Scientific workers owe a debt to the authors of this volume, which only those who have attempted to collect such numerical results can fully appreciate

ISSN:0028-0836    

DOI:10.1038/119193a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

AN examination of the very extensive literature dealing with the function of phosphorus compounds in the chemical mechanism of muscular contraction reveals so many contradictory statements that it is evident that the technique in use must be subject to some serious fault. Since we have found what is probably the main cause of the discrepant results obtained in this field, it seems desirable to communicate our results without delay.There appears to be in muscle tissue an organic phosphorus compound which, by reason of its great instability in acid solution, has been confused hitherto with inorganic phosphate, to which it gives rise in the course of the estimation of inorganic phosphates by the methods of Embden or of Briggs, or by any method involving the use of mineral acid. The confusion is increased by the fact that this substance, the organic phosphorus compound which we have designated 'phosphagen,' is intimately connected with the chemical mechanism of contraction; the estimation, therefore, of 'inorganic' phosphate by the above methods is hopelessly misleading, since by them one measures the sum total of two substances which vary independently in amount. It is possible, by avoiding the use of acid solutions, to estimate true inorganic phosphate, since 'phosphagen' appears to be stable in neutral or slightly alkaline solution. The following table, which concerns the gastrocnemius muscle of the frog, illustrates the changes in the amount of phosphate and 'phosphagen' in a muscle subjected to different treatments: Incubation in Resting. Rapidly Heat ]NaHCO. Fatigued. Rigor. Without With NaF. NaF. Inorganic phosphate . . 20 50 90 110 20 'Phosphagen' 65 25 0 0 0 Sum total . 85 75 90 110 20The figures are given as milligrams of phosphorus per 100 gm. of muscle, and are representative of a number of experiments. The third row of figures corresponds to the 'inorganic 'phosphate as estimated by the ordinary methods. These facts suffice to explain many of the anomalies to be found in the literature. We will deal here with only one of these. Embden and his co-workers have noted a disappearance of inorganic phosphate in a suspension of minced muscle in sodium fluoride solution. Thev have attributed this to a synthetic action of the fluoride ion. Comparing the first and last columns in the above table there is an apparent synthesis of 65 mgm. of 'inorganic' phosphate into something not estimated by the Embden technique. The real state of affairs, however, seems to be that the true inorganic phosphate is not affected at all. Either the fluoride ion catalyses the conversion of ' phosphagen' into some acid-stable compound, or else it poisons a catalyst which normally causes its transformation into inorganic phosphate. Rapidly induced fatigue produces a similar but smaller effect.One further point of interest worthy of note here is that while unstriated muscle contains about the same amount of genuine inorganic phosphate as does striated (skeletal) muscle, it appears to contain no 'phosphagen.' The heart muscle of the frog also gives about 20 mgm. of inorganic phosphorus per 100 gm. of muscle, together with a slight but definite amount of 'phosphagen.' One is tempted to correlate the ' phosphagen ' content of a muscle in its resting condition with its ability to respond to sudden demands for violent activity. Whilst we have at present no definite knowledge of the nature of this substance, it seems quite possible that it may be the unstable ('active') hexose monophosphate, the existence of which was inferred by Meyerhof in interpreting the phenomena of glycolysis in cell-free muscle extracts, and the fermentation of sugar by yeast.

ISSN:0028-0836    

DOI:10.1038/119194b0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

IN connexion with some experiments, I was led recently to estimate the extent to which a large number of receiving aerials would contribute to the absorbing effect of the earth's surface on wireless waves in resonance with them. A short calculation showed that, with a density of aerial distribution such as now exists in an urban district surrounding a local broadcasting station, the energy absorbed by the aerials should be the decisive factor in determining the surface attenuation. Since the aerials would naturally only effect those waves which were very close to wave-lengths to which they were tuned, it was not difficult to test this conclusion. A number of experiments have been made on the general principle of measuring the intensity of waves which have travelled across a considerable area containing large numbers of broadcasting aerials, the wave-length being gradually varied from just below to just above the normal wave-length of the local broadcasting station (2 LO) to which the majority of the aerials may be assumed to be tuned (that is, a wave-length of 364 metres).These experiments, which were carried out with the assistance of Dr. Smith-Rose and Mr. Munro, with the kind co-operation of the B.B.C., have yielded results that constitute very definite evidence of a critical effect of large magnitude occurring at or near the resonant wave-length, and the phenomenon appears only ascribable to the selective action of the multiplicity of tuned aerials in the path of the waves. Thus, at Slough (see Fig. 1), when receiving from the 2 LO transmitter at Marconi House, an increase in intensity of the order of 90 per cent. was observed for a variation in wave-length of only 5 per cent.; while it will be seen that for a wave-length change of 120 metres a total increase of field strength of nearly five to one was obtained; that is, for a given power transmitted, the received power increased more than twenty-fold. Now the hypothesis that this effect is mainly due to the transmitted waves passing in and out of resonance with the aerials in their path is confirmed 40 so ao .II I * 0 I 10 1 RESONANT:/NAVEf LENGTHA 40O So0 200 METRES 300 Wave-length Ple. 1.-Effect of wave-length change on received field strength. Transmitter-2 LO. Receiver-Slough. by the fact that the effect was found to increase in proportion to the distance which the waves travelled over crowded residential districts, and was negligible when the wave path lay almost entirely over open country with only a small residential area round the transmitter. The hypothesis was further confirmed by the fact that the effect was shown not to be peculiar to a given transmitter or receiving site. On the other hand, it seems at first to be contradicted by the fact that the minimum intensity, and therefore apparently the maximum absorption, does not occur at the resonant wave-length but at a wavelength considerably below. In some cases the minimum had not been reached at 300 metres, below which wave-length experiments have not yet been carried. A brief study of the theoretical side of the problem, however, shows that this is not necessarily the case. If an electromagnetic wave is propagated in a medium containing resonators of all one periodicity, it is well known that, on varying the wavelength of the waves in the neighbourhood of the resonant value, there is a critical change in the medium, not only of its absorption factor but also of its refractive index, the latter being responsible for the optical phenomenon of anomalous or selective dispersion. Now there is an undoubted analogy between this and the experiments under discussion. The medium containing resonators is in this case the layer immediately above the earth's surface containing the tuned aerials. We must, therefore, take into account the possible effect of a change in the refractive index of this medium as well as in its absorption factor. But the theory of wireless wave propagation as developed by Sommerfeld and others shows that the former factor may be as important as the latter in determining the attenuation which the waves will experience in passing over the earth's surface. Finally, the theory also shows that a variation of the refractive index with the wave-length in the manner demonstrated in theoretical and experimental optics in such circumstances (anomalous dispersion) would have a tendency to cause the point of maximum attenuation (and therefore minimum received intensity) to be shifted to the left of the critical wave-length line, as it was found to be from observation. This is manifestly only a tentative explanation, but it is enough to show that this unexpected feature in the experimental results does not invalidate the general conclusion that the large number of receiving aerials in the London area have a very marked absorbing effect on the waves passing over them.The observations on which the above note is based were carried out as part of an investigation for the Radio Research Board of the Department of Scientific and Industrial Research.

ISSN:0028-0836    

DOI:10.1038/119195a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

WHEN the collisions between the molecules of an ideal gas are taken into consideration, then the motion of the gas does not appear to be multiply periodic. It is therefore impossible to quantise this motion by means of the ‘classical’ quantum theory. Moreover, in the treatment of the ideal gas by means of the new ‘undulatory mechanics,’ hitherto only the impenetrability of the walls of the vessel has been taken into account, and not the reciprocal impenetrability of the molecules (E. Schrödinger,Phys. Zs., 27, 95, 1926). I propose to show here that, in the case of impenetrable moving mass-points, wavemechanics gives an exact and very elementary solution. Simultaneously we arrive at the relation mentioned in the title.For purposes of brevity we will limit ourselves to a 'one-dimensional' gas: N monatomic mass-points of equal mass M are enclosed in a tube, which extends from x = to x = + 2 If we first take into account 2 2 only the impenetrability of the ends of the tube, then we have to look for all the solutions of the N-dimensional Schrodinger-equation: 2 + a + * *x? Ci + M7]J = (1) which are equal to zero at the faces of the N-dimensional + 2-cube. These solutions are: =cos al xcos a2X2 . . . Cos aNXN, . (2) where a, . . av are arbitrary positive integers and where E = 8 k~aii2 + . . . tt2y). To the same E, and with the same numbers a, . . . aN, there belong also all the solutions obtained from solution (2) by ex changing all the co-ordinates x1 . . . ZN with each other, at the same time keeping the numbers a. . .. aN fixed. By multiplication of all these solutions by arbitrary constants and addition, we obtain the most general solution of this kind: q' = 0C(PI ... PN) cos a1XP, cos a2X5P . . . cos aNpNN, (3) where p1 . . . PN signifies one permutation of the numbers 1 . . . N, and the summation must be taken over all the permutations.Now let us also consider the reciprocal impenetrability of the molecules. That can be done by means of the additional 'diagonal-restriction'; which in wave-mechanics corresponds to the impossibility of two molecules occupying the same point in space at the same time. Of all the solutions of the form (3), only those are allowed which are also equal to zero at all points of the N(N 1) flat 'diagonal-spaces' 2 of N 1 dimensions which are represented by the equations x, = Zk(h, k = 1, . . . N). It can be shown now best by considering first the cases N= 2 and N = 3 that all the constants 0(pi . . . PN) must have values equal to each other or opposite in sign, according as the arguments Pi . . . PN are derived from the numbers 1 . . . N by an even or an odd number of simple permutations. Or, in other words, because of the reciprocal impenetrability of the molecules only the antisymmetric solutions are allowed: COS ai1X . . . COS aIXN qantisym (xl . . ZN) = C. COS aNXl ... COS aNXN (4) Thus, just those solutions which, according to the researches of Heisenberg and Dirac, are connected with Pauli's exclusion principle (the exclusion of equal quantum numbers for two electrons in the same atom-in our case for two gas molecules in the same vessel), the determinant becomes identically equal to zero when two of the numbers a. are equal to each other.Finally, we may remark as follows: I. For a three-dimensional gas contained in a vessel of general form, naturally py (xyz) must be substituted for sin ax; further, in the 'diagonal-restriction' the equations (X, X,)2 + (y, yk) + (Z, Z,)2= 0 for xh = xZ, and we have always to exchange a triplet x,yz, with a triplet XkYkZk. II. In order to show that the impenetrability of the walls and for the molecules must really be expressed by the corresponding zero-conditions of the solutions of the Schrddinger equation, we approximate first this impenetrability by continuously varying forces of repulsion and then we go in the resulting solutions to the limit.III. At the same time we get very simple models for the treatment of the question of how far the Pauli's exclusion principle holds for two electrons if they are in the same atom but not if they belong to distinctly separated atoms. IV. The non-validity of Pauli's principle for 'lightcorpuscles' should now perhaps be connected with their reciprocal penetrability, though the very provisional and symbolical character on one hand of the light corpuscles, and on the other of the multidimensional wave-equation (1), should specially be remembered here. These remarks and some connected statistical questions will be dealt with e

ISSN:0028-0836    

DOI:10.1038/119196a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

IF under “Treasury” Prof. Troup includes the Colonial Office and Forestry Commission (the latter two offices defraying the bulk of the expenses of the Institute at present), the tax-payer, whether in Britain or overseas, will be relieved to have the assurance.Prof. Troup's somewhat ex parte account of the proceedings leading up to the inauguration of the Institute in 1924 has in one form or another appeared on several occasions in the Press. He does not, however, appear to realise that a growing body of scientific opinion is at the back of the representations which the authorities of the Universities of Cambridge and Edinburgh placed before the Secretary of State for the Colonies and members of thd Forestry Commission on the subject of the concentration of (Statesubsidised) post-graduate forestry work of all kinds at one university. The authorities of the two universities stated quite definitely that they had no intention of giving up the post-graduate courses they had already inaugurated, and all they asked for was an ' open door.' It is understood that the Secretary of State accorded a sympathetic hearing, and intimated that whilst nothing could be done at the moment, the experiment was only made for a five-year period and would be open to a reconsideration at the end of the per

ISSN:0028-0836    

DOI:10.1038/119197b0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature