摘要:

MR.RAMSAY MACDONALD, during the MT brief existence of the first Labour Government, must have established a record in the number of special committees of inquiry which he appointed. Not the least important was the Committee appointed to inquire into the conditions and prospects of British industry and commerce and to make recommendations in regard thereto, the general scope of the inquiry to include a survey of overseas markets, a survey of industrial relations, and an assessment of British productive capacity and its efficiency. The report of the Committee is being presented in parts; the first part, dealing with overseas markets, was published in June 1925; in February 1926 a volume appeared dealing with industrial relations; and now, after an interval of a year, a third volume has emerged as a first of two contributions to the subject of productive capacity and efficiency. When this Committee was about to be appointed, it may be remembered that doubts were expressed regarding the capacity of a Committee composed solely of representatives of finance, industry, and trade to deal adequately with the proposed terms of reference. Major Church, speaking in the House of Commons to the resolution which led to the inquiry, urged the inclusion of representative scientific workers on the Committee, pointing out that they would be in a better position to estimate the possibilities of future trade developments and to appreciate the effects likely to be produced on our commerce by the applications of science to agriculture-the foremost industry of the Empire -and those industries the future of which is indissolubly bound up with the progress of scientific research, than representatives of the classes of the community specifically mentioned. But Mr. Sidney Webb, on whose advice the Committee was appointed, held to the theory that those who would be chosen to represent science on such a committee would necessarily be creative workers whose time would be better occupied in discovery: consequently, scientific workers were neither represented on the Committee nor have they been given the opportunity of expressing their views on the present relations between industry and science. The Department of Scientific and Industrial Research has dealt with that aspect of the inquiry.This third volume is disappointing. It consists mainly of reports and memoranda prepared by various government departments or officials. There are a brief half-page summary of the work of the National Institute of Industrial Psychology based on the evidence of the Director, and a chapter on industrial art prepared by the British Institute of Industrial Art. Without further inquiry or reference to other bodies, the Committee has prepared a long introductory, inconclusive summary of the subjects dealt with and views expressed in the remainder of the volume. No recommendations are made, only rarely a hint of a suggestion creeps in for the improvement of industrial efficiency in Great Britain, a complacent air of Micawberish optimism pervades most of the pages, but above all, a veil is drawn over the operations of the banks and financial houses of the country-for the present at any rate. The report gives the impression that all will be well when Great Britain has recovered from the destruction of the new things it created in addition to its normal needs during the War, rather than when it has decided to apply the newest advances in scientific knowledge to industry, under the comparatively unfettered direction of those who understand the creative ideas and forces with which they are dealing. Whether the Committee is dealing with industrial structure, the training and recruitment of manual workers and higher technical and professional staffs, standardisation of units of measurement and materials, the function of scientific research, the encouragement of industrial arts, State measures for encouraging home industries and overseas trade, the effect of national and local taxation on certain industries, with all of which this volume deals, it remains entirely non-committal, and the report could be used equally well as a brief either for those who wished to take no action or for those who wished to attempt to improve British industry and trade.Nevertheless, the memoranda submitted by State departments and other bodies and embodied in this report are of the greatest interest: those on " Industrial Structure " furnished by the Board of Trade, on " Technical Education " by the Board of Education and the Scottish Education Department, and " Industrial Art " by the British Institute, being particularly noteworthy contributions. The chapter dealing with industrial structure gives an account of the marked trend during the last quarter of the nineteenth century towards the limitation of competition in each of the highly industrialised countries and its later development. The information given is already in the possession of certain sections of the community, but it is the first time, we believe, that it has been summarised in an official publication. One of the most disquieting features in modern industry is the loss of skill which accompanies the growth of large-scale machine production. The old traditional crafts, in which the individual carried an article through all stages of its manufacture, are now fast being displaced by massproduction, where the individual is responsible for one of the various processes of manufacture. The problem of creating and maintaining skill in craftsmanship is one of the crucial problems of modem industry. For this the Committee supports the view of the Board of Education that we must look to the schools rather than to the workshop. The subject of technical training is dealt with at some length. In view of the clamour among certain classes of employers for early vocational training, the Committee is to be congratulated on expressing its conviction that education is a preparation for life, and its wider aims and functions should not be sacrificed or subordinated to the demands of industry and commerce.A somewhat gloomy picture is given of the dependency of Great Britain on the Continental designers for art applied to industry. Too many firms rely entirely upon Paris for their designs and thus tend to limit more and more the creative potentialities of their own designers. Yet, as it is stated, the artist does not flourish in the ugliness of a northern manufacturing city. " Frenchmen working in Manchester are said to lose their native gifts after three or four years." The British artist evidently suffers, like the scientific worker, from lack of an environment congenial to his task and the narrowness of outlook of industrial leaders. He suffers from the further disadvantage that the developments of the great machine industry had at the outset " the most disturbing and often disastrous effects on industrial art by breaking up the old craft traditions, revolutionising technique, and weakening or severing the close relations which previously existed between designer and executant." Emphasis is laid upon the growing complexity of modern commerce and the obvious need for systematic training in economics and finance. " The fact that the demand for higher commercial teaching of University rank has emanated from economists and educational observers rather than from the representatives of commerce, does not substantially weaken the case for such education, for almost exactly the same observation could have been made a generation ago with regard to forms of technical and scientific instruction which have now become firmly established." In dealing with the subject of scientific research the Committee has relied upon the memorandum furnished by the Department of Scientific and Industrial Research. Other government departments which might have made equally useful contributions to the subject have not been given the opportunity of presenting their views, and apparently the views of leading manufacturers have not been independently ascertained. The Committee states what scientific workers have long known to be the case, that there is still a very imperfect recognition by the industries of the need for the continuous and systematic application of scientific methods both to the invention and improvement of particular methods and processes of production, and to the enlargement of the boundaries of knowledge with regard to the fundamental underlying principles. Most of the scientific workers engaged in industry are absorbed in " tactical research," that is to say, the improvement and development of existing processes, and very few in " strategical research," i.e. the search for new products or processes or to the investigation of fundamental laws. The cost of strategical research is usually beyond the means of individual firms, and only the great combinations can afford to embark on such enterprise. The Committee is forced to the conclusion that " freedom and flexibility are essential conditions of fruitful research " and urges the need for the demarcation of functions in the matter of research between the State, which could and should encourage this freedom, and private enterprise, which will usually have a tendency towards secrecy. It is unfortunate that the Government which appointed this committee did not adopt the suggestion made to bring the representatives of science in intimate contact with the leaders of industry and finance. Had this been done, the chapter on research might have concluded with definite recommendations instead of vague generalities and aspirations. But the fault lies with scientific workers. They fail to realise the urgent need of putting themselves in a position to demand representation on all such bodies. Though faced with every form of combination among financiers, employers, and manual workers, they neglect to combine themselves for the furtherance of their legitimate interests; and while they remain unorganised they can scarcely expect to be considered as a driving or united force in public affairs which affect them as well as the nation.Committee of Industry and Trade. Factors in Industrial and Commercial Efficiency: being Part I. of a Survey of Industries. With an Introduction by the Committee. Pp. v+544. (H.M. Stationery Office, 1927.) 5s. net.

ISSN:0028-0836    

DOI:10.1038/119305a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THE advance, and indeed the proper compreTension, of evolutionary philosophy is to-day suffering greatly from the increase of specialism. This specialism is to a great extent inevitable, but it is at least in part due to an unfortunate byproduct of the spreading appreciation of the value of research. The educationist realises that there is no finer training than that which is gained by the conduct of a piece of original investigation. The community as a whole, too, is beginning to appreciate, even though dimly, the extent to which scientific research enters into the foundations upon which rest the health and comfort and prosperity of the modern civilised state. While this growing appreciation brings with it advantage to the cause of science and to the welfare of mankind, it is not without its disadvantages. Young men without conspicuous natural qualifications are turned on to do a bit of research for their own personal advantage. This is all to the good: they are bound to benefit greatly by being put through the necessary discipline. The harm comes when such prentice efforts are published without due consideration. The work may be simply of inferior quality, or if sound it may be that poor kind of research which consists merely in the transference of certain facts in Nature, of no apparent significance, to the pages of a printed book or journal. Above all, there is the natural tendency, and not merely for beginners, towards intensive research in some very restricted field. The myopia induced by such intensive study necessarily involves disability to broader vision-a disability of which the patient is often completely unconscious-and we find the narrow specialist laying down the law as regards the problems of evolutionary philosophy in a way which even an elementary grasp of those portions of the subject lying beyond the limits of his own speciality would restrain him from doing.In General Smuts we have a visitor to the domain of biology from very different fields of activity, and as he comes armed with credentials of the highest order-testifying to his intellectual power, to his honesty of purpose, and to his remarkable freedom from prejudice-it becomes of extraordinary interest to scan his vision of evolutionary philosophy, free as it is from the distortion and disturbance of true proportion which specialist concentration on little bits of the subject is so apt to induce. The first four of the twelve chapters of " Holism and Evolution " are devoted to those fundamental concepts which underlie the general theory of evolution, to the ideas of space and time and matter, and to the cell and the organism. To the present reviewer, who believes that the lapse of timewith the truer proportions that distant vision gives-will show the figure of Charles Darwin towering alone above all others in the history of philosophy, it is particularly agreeable to see that General Smuts appreciates, in a way that the biological specialist so often entirely fails to do, the unique position occupied by Charles Darwin.While emphasising in this introductory portion of the book the importance of increased precision of nomenclature, it is perhaps disappointing that the author has not handled the tangle in which so much modern discussion has become tied up in the misuse of the word ' space.' The conception of space is derived by a simple step from the sensory perception of the extension of material objects, by merely ignoring the material substance of which they are composed. That gives us the primitive idea of space, and this space is in its essence tridimensional. When the pure mathematician for his own purposes modifies this idea by removing or adding one or more dimensions, we are apt to forget that in doing so he has interfered with the fundamental conception of space as derived from our sensory experience of the material world. No harm is done in the realms of pure mathematics: the danger comes when such expressions as' space' of one, or of two, or of n dimensions, are brought back into speculations regarding the material universe, for confusion of ideas is the immediate and inevitable result. In the following chapters of his book the author develops his philosophy of Holism. " The close approach to each other of the concepts of matter, life, and mind, and their partial overflow of each other's domain, raises the question whether back of them there is not a fundamental principle of which they are the progressive outcome."Evolution to the author is not the process expressed by that word taken literally-a mere unfolding of complexities already present-but is actually creative: " it creates both new materials and new forms from the synthesis of the new with the old materials." Surveying the world of Nature, the author sees its great characteristic in the tendency to the development of 'wholes.' To illustrate what he means by wholes, he cites the case of living organisms, each made up of constituent parts but yet possessing an individual specific character of its own. Although particularly obvious in the case of animals or plants, such wholes pervade all Nature-not merely the material world with its atoms, molecules, and chemical compounds, but also the immaterial world which includes human ideals and performances. Everywhere we find 'wholes ' basic to the character of the universe, and " Holism as the operative factor in the evolution of wholes is the ultimate principle of the universe." This, then, is the kernel of General Smuts's philosophy-that the universe is vitalised by a great driving force-its inherent tendency towards integration into more and more highly developed wholes, into the more lowly types seen in inorganic Nature, the higher types seen in living creatures, and finally the highest types of all on the artistic and mental and spiritual plane of existence. " Holism in all its endless forms is the principle which works up the raw material or unorganised energy units of the world, utilises, assimilates, and organises them, endows them with specific structure and character and individuality, and finally with personality, and creates beauty and truth and value from them." A great idea surely, and one which justifies the author in putting forward his claim that it brings us nearer " the monistic conception of the universe which is the immanent ideal of all scientific and philosophical explanation."In a series of interesting chapters the theory just outlined is elaborated, one of the most interesting being that entitled " Darwinism and Holism." Here again full tribute is paid to the greatness of Darwin: " He has changed our whole human orientation of knowledge and belief, he has given a new direction to our outlook, our efforts and aspirations, and has probably meant a greater difference for human thought and action than any other single thinker." Perhaps still more remarkable than the author's appreciation of Darwin is the fact that he has succeeded in maintaining his balance in regard to Mendelism, and has firmly placed it in proper perspective in relation to the general theory of organic evolution.An acute discussion of Weismann and his work leads to the much-debated question of the inheritance of impressed characters, in which the author shows a distinct leaning towards accepting their transmissibility, incidentally testifying to the impression made upon him by Bower's discussion of the matter in relation to evolution in the vegetable kingdom. Repeatedly we come across the suggestion that such impressed or ' acquired characters may be inherited. The position taken up, however, by those of us who feel constrained to keep such characters outside our evolutionary speculations, is not that we dogmatically deny that they may be inherited, but rather that we deny the existence of the overwhelming body of evidence that they are inherited, which we believe would inevitably be forthcoming were this the case.An interesting feature in this chapter is that the author shows that he fully realises the prevalent error of thinking of small variations in detail by themselves, and stumbling over their selective value, instead of bearing in mind that these details are merely parts of a physiological whole and that the actual selective process deals with such complete individuals. It is very true, and it is, in these days, really necessary to drive it home, that "there is no doubt that experimental evolution has, through its unavoidable limitations, greatly blurred the great Darwinian vision of organic evolution," and " natural evolution as distinguished from experimental evolution is a process, not of the hour or the day, but of geological time, and the results, consolidated through immemorial periods, cannot be repeated or rehearsed by short-dated laboratory experiments."What Darwinism does not explain, or purport to explain, is the origin of the variations which form the raw material upon which natural selection works. To the present reviewer that raw material is provided by the instability or variability which is essential and inherent in the nature of life itself. To the author of Holism it is given by a universal tendency to undergo change in the direction of higher and higher integration. As regards the general thesis of Holism, probably most men of science will find themselves in agreement with the author so far as the evolution of the universe as a whole, meaning by that the sum of all existence, is concerned. There must have been inherent in that from the beginning a creative power which has found its expression in all subsequent developments. Some, with General Smuts, will spell it Holism: some will spell it God.Many, however, while accepting the argument for the universe as a whole, will feel doubts as to their being constrained to do so for its constituent parts. When dealing with any one of these we are no longer dealing with something that is absolutely self-contained: it now has an environment; and the doubt arises whether the environment, taken in conjunction with the instability which modern physics would appear to extend even to the minutest particles of ' dead' matter, may not have a moulding influence sufficient to account for evolution. Enough has perhaps been said to achieve the purpose of this review-to direct attention to a remarkable and important work which should be read by all interested in the philosophy of the world in which they live. As will have been gathered, General Smuts' book is a step towards that merging together of science and philosophy which is bound to come at no distant date. Men of science and philosophers alike are aiming at the same objective-the unravelling of the meaning that lies behind phenomena.Such basic ideas as space and time are no longer placed apart as a priori in their nature: it is realised that each is a simple development from sensory experience. The man of science believes that, with the foundations of his philosophy laid in experience, he is logically bound to keep in touch with experience throughout the whole process of building up that philosophy of the universe in which he lives. He realises that as he builds he must make use of every possible refinement of technique, whether of observation or of mathematical or other methods of working up the data obtained by observation. With both sets of workers striving onwards towards the same goal, it will not do for either to ignore any methods of technique that will help them on their way, and when once this is fully realised and a common technique adopted, we shall have at last a unified army marching onwards to the attack of ignorance, and it will be of little moment whether its banner is inscribed 'science' or I philosophy.

ISSN:0028-0836    

DOI:10.1038/119307a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

GEOLOGISTS will be deeply grateful to Prof. ' Obrutschew for his masterly summary of the geology of Siberia, since so much of its extensive literature is in Russian and therefore inaccessible to most western workers. His book will form a standard work of reference for the geology of northern Asia, owing to its concise summary of the available information, its clear discussion of the chief stratigraphical and tectonic problems, its admirable series of sketch maps, and its full bibliography. Prof. Obrutschew divides Siberia into seven geomorphologic units, including the Scheitel of Suess, to which he refers as the kern, and therefore justifies the translation of the term as core or nucleus. He prefers to call this area the SayanBaikal Highlands, but Suess's explanation of its significance is confirmed, as the Jurassic and Kainozoic deposits upon it are horizontal. The most serious modification in Suess's interpretation of the structure of Asia is in connexion with the Altaids; Prof. Obrutschew shows that Suess has included in his Altaid Mountain Systems elements of different ages, trends, and origin. Some of the east Altai folds are Caledonian, and some, such as those of the Saur-Tarbagatai and the Tien Shan, are later. Prof. Obrutschew therefore excludes the Tien Shan ranges from the Altaids and restricts that term to the Altai, the Khirgiz folds, and the Siberian Hercynian movements. Suess's objection to the term Hercynian, however, still stands, and his suggestion of Altaid as the name for the widespread mountain system that was formed toward the end of the Paheozoic and includes American, European, and African as well as Asiatic mountains, remains unshaken by these restrictions.In the long succession of marine deposits in Siberia most of the geological systems are represented, and they throw light on many problems. Thus, in reference to the current discussion upon climate and continental drift, it is interesting to note that the Siberian marine faunas from the Cambrian to the Upper Kainozoic all have features indicative of a northern zone. The fauna which suggests the warmest conditions is that of the Silurian, which is described as being rich in corals; but they are mostly either simple or Alcyonarian, and do not indicate such warm conditions as rendered possible in England the growth of the contemporary coral reefs and those of the succeeding Devonian. The Tethys once spread northward so far as the Siberian Islands, but its fauna there consisted mainly of ammonites, and was consistent with a moderately cool sea. In the Cretaceous, which is so often claimed as having had an Arctic tropical climate, the marine fauna was rich in Aucella, and the one coral quoted from Siberia is a simple form, a Microbacia, and these fossils might have existed in a sea as cold as the present Arctic Ocean. The work follows quite different lines from the recent discussion by Prof. Argand of the tectonic of Asia. It is a summary of the facts with such discussion as is required to make them intelligible and interesting, and will be an indispensable book of reference in regard to Asiatic geology.

ISSN:0028-0836    

DOI:10.1038/119309a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

SPECIALISATION in science, and the organis sation of research, undoubtedly lead to rapid advance in the elucidation of particular groups of phenomena; but they are also responsible for systematic neglect of others. Thus there remain dark corners into which the investigators of the last century swept the trifles which they preferred to leave unconsidered. For a hundred vears after Cavendish had shown that a portion of atmospheric nitrogen, after being ' sparked' with oxygen, always remained uncombinable, chemists deliberately ignored this residuum; yet soon after Rayleigh and Ramsay turned their attention to it, the sky-signs of London were advertising by the glory of their colours that there was indeed something in it. When this has been possible in chemistry's diligently cultivated field, may we not hope to find much more lurking in those obscure plapes where none of the recognised sciences has as yet pegged out a claim ?The use of the divining-rod in the discovery of springs has long been looked at askance by men of science, and not altogether without reason. People who profess to be dowsers, though usually honest folk, are sometimes fools deserving the application of their rods to their own backs, as Prof. C. V. Boys hinted in these columns a quarter of a century ago. Occasionally they are pernicious paradoxers or, rarely, unblushing impostors; yet it must be acknowledged that none of those who essayed to prove that there was nothing but folly, perversity, and imposture in this method of water-finding, has succeeded in explaining the unquestionable facts. Every one who has had to do with the water-supply of country houses knows that dowsers do find water. To ignore problems for fear that their solution might involve methods beyond the domain of conventional physics is no more justifiable than would be the banning of research into protons and electrons lest it should lead the investigator beyond the sphere of Daltonian chemistry. Many years ago Sir William Barrett defied scientific prejudice and took up the study of dowsing. He devoted so much time to the diviningrod in literature and in practice that a systematic statement of his results has been awaited with interest and curiosity. Unfortunately, he died without completing the classification and discussion of the mass of data in collecting which he had written, as the preface tells us, between 6000 and 7000 letters. Some months before his death, he had secured the co-operation of Mr. Theodore Besterman, with whom he discussed the whole subject, though for the actual arrangement and writing of the book before us the junior colleague accepts full responsibility.Although the book makes very interesting reading, its arrangement is far less satisfactory than the orderly subdivision in the table of contents might suggest. Mr. Besterman devotes 250 pages to evidence of the reality of the finding of water (and incidentally other things) by the divining-rod, and only about 50 pages, many of them straying back to the earlier theme, to an attempt to explain the mechanism and rationale of the process. The work is divided into three parts. Part I. is entitled " Historical and Geological." The historical portion, after touching on the rise of dowsing in the fifteenth century, gives interesting details of the performances of three famous French dowsers for minerals and water and the tracking of criminals. It includes the strange case of the Abbe Paramelle, a water-finder who used no divining-rod and disclaimed any super-normal powers, yet the authors have decided that he was a dowser malgre lui. Much of the geological discussion strikes us as irrelevant and unnecessary, it being clear that none of the famous dowsers had any geological knowledge whatever and could not have located water by the lie of the sub-surface rocks. Part II., though entitled "Experimental," consists of descriptions of the exploits of a large number of recent and contemporary water-finders similar to that given in Part I., with details vouched for by numerous well-known or highly respectable authorities. Three appendices cite other cases which might appropriately have come in Parts I. and II. Even the short " Part III., Theoretical," continues to adduce fresh evidence as to successful dowsers while setting forth the explanation of the action of the divining-rod arrived at by the authors. There is an excellent index, which will prove useful to students of the subject, and an extensive bibliography, which might have been improved by providing some indication of the size of the books cited.As to the value of the whole discussion, Mr. Besterman says in his preface: " Whether the results justify this labour it is for the reader to decide; but should it be agreed that the ability to find hidden objects by other than normal means has been established, the question can hardly be answered otherwise than in the affirmative."This is not happily worded, for it fails to define the critical term normal, and by extending the use of the divining-rod from the well-established case of water-finding to the detection of minerals, corpses, and even murderers, it makes room for the intrusion of false issues. Sir William Barrett probably went beyond the comparatively simple case of the divining-rod in water-finding because he hoped to reach in one stride an explanation which should include all kinds of cognition of objects undetectable by the 'five senses.' We agree that the evidence brought forward in the book proves the existence of a power in some people, of both sexes and of every age, race, and social position, of detecting underground springs of water which can neither be seen, heard, smelt, felt, or otherwise perceived by the vast majority of mankind. Further than this we are not prepared to go, nor do we think it necessary to seek more recondite explanations until all reasonable hypotheses for bringing the phenomena into line with the recognised or discoverable processes of Nature have been exhausted. The suggestion that radiation or vibration of some kind issuing from running water underground may be detected by the nervous system of the dowser in virtue of some hyperaesthesia is dismissed too curtly (p. 261) as " terminological perversity." The comprehensive explanation which Mr. Besterman tenders in the names of Sir William Barrett and himself (p. 267) to cover all cases of the dowser's detection of hidden things is: " The several categories of phenomena surveyed above appear to us to lead inevitably to the conclusion that no physical theory can cover the facts. In our view the phenomena of dowsing are due to the following causative chain of psychological and physiological happenings: a suggestion is received by the dowser's subconsciousness by means of a sensibility as yet unknown to us and therefore admirably named by M. Richet cryptesthesia; . the knowledge thus supernormally obtained can become conscious: . . . (1) if the person is one whose access to, and ability to become conscious of, knowledge in his subconsciousness is more continuous and complete than those of the normal person, the cryptesthetic suggestion received by his subconsciousness can almost simultaneously become conscious. . . (2) By means of unconscious, automatic movements such as those whichprovide the phenomena of automatic writing. . . . Intermediatelv between these alternatives may be placed (3) those reactions of the subconscious suggestion which cause the phenomena which may be comprehensively described as the malaise of the dowser." Here a fallacy may lurk, for if " a sensibility as yet unknown to us " is conjectured as conveying cognition to the subconscious whence it obscurely wriggles into the conscious mind, could the unknown sensibility not be as easily conjectured to appeal direct to the conscious mind ? If cryptoesthesia is a " sixth sense," as M. Richet suggests, may it not be a sense capable of appreciating directly some physical property of the hidden object? This appears to be Prof. Richet's own view if we translate rightly his letter in NATURE for Dec. 18 (p. 876) on the explanation of " spiritualistic " phenomena:"The hvpothesis of unknown vibrations seems to me preferable. After all, why not suppose that reality emits vibrations ? Do we not know of innumerable powerful vibrations such as electric and magnetic waves which are only revealed by special detectors and would pass unperceived without the use of these detectors ? " Thus Prof. Richet seems to countenance the idea which occurred to us, before his letter appeared, in reading Sir William Barrett's book, that the malaise of crypteasthesia may be akin to that experienced by some people in thundery weather, which can reasonably be attributed to the action on the nervous system of the electric waves announced by wireless 'atmospherics' in advance of thunderstorms. Investigation must prove whether this is so, or if the recognised senses may in some people attain a state of hyperoesthesia and become capable of acting much more powerfully than under usual conditions. May not some people have a sense of smell (if it is smell) as highly developed as that of the dog which perceives in the dark outside a house the room in which his master is; or a sense of hearing or touch as fine as that of the bat, if that animal indeed navigates dark winding caverns by means of a natural power of echosounding ?It may be the prejudice of the student of measurable and calculable things which makes the hypothesis of cognition through the unconscious mind repugnant as an instrument of scientific research, or it may be ignorance of psychological methods which makes us incapable of being convinced by the arguments, while accepting the facts, brought forward in this book. Whether his explanation is right or wrong, Sir William Barrett deserves to be held in grateful memory for accumulating by his enthusiastic labour such a rich store of obscure facts. It is to be hoped that the book will inspire some open-minded investigator versed in physiology and adequately instructed in physics and psychology to make an exhaustive experimental study of the mechanics of the divining-rod and the concurrent physical and mental state of the dowser, with the sole object of seeing how it is done. Observers who take up the subject determined to prove that the whole thing is a piece of humbug, can of course discover nothing.

ISSN:0028-0836    

DOI:10.1038/119310a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THE scope and purpose of this work is sufficiently explained by the following extract from the preface: " There is need for a new publication which would record, in a concise form, and in language easily understood by the non-scientific, but practical, man all the results of scientific work carried out, not only in Britain, but in other parts of the world, so far as it has bearing on agricultural practice at home." This preface is signed "Devonshire, Chairman Research Committee, Royal Agricultural Society of England." There follow five compilations by recognised authorities on each subject, dealing specially with research 'results ' in veterinary medicine, soils and manures, animal nutrition, dairy husbandry, agricultural economics, and agricultural engineering. No one can quarrel with the merits of the work; each section will certainly prove of interest to research workers in each particular field. But doubts may be expressed as to its intelligibility to the " non-scientific but practical man " (the italics are ours-the antithesis is, we hope, unintentional). Much of the language used implies some knowledge, not only of strictly scientific terms (such as metabolism), but also of ideas expressed in an ordinary language (e.g. energy) with which. the 'practical' man is not familiar. Be that as it may, the names at the head of each section are a sufficient guarantee that the information given is trustworthy and that the praiseworthy objects of the leading agricultural society in Great Britain have been worthily achieved.

ISSN:0028-0836    

DOI:10.1038/119312b0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

A ROAD TO FAIRYLAND" is dedicated to "all children between the ages of seven and seventy," and the author has indeed provided a variety in her twelve stories in which something should please her clientele at every stage within these limits of their years. Here and there we catch an echo of the folk tale; but the author has a subtle power of invention and a felicity of phrasing, as well as a humour, now delicate, now broad, which have carried her well on the way to success in the bold and risky undertaking of writing fairy tales. One feature in these stories may be held by some to be open to question. In most of them a moral is to be discerned, and sometimes it is explicitly stated in the good old-fashioned way at the end. The moral has long been condemned; but the healthy normal child does usually love a moral. It is infancy's equivalent to the triumph of virtue in the melodrama of days gone by. Of individual stories, the one with which the book opens, " The Princess," is perhaps the best. It exhibits a knowledge of human nature and a philosophy which makes the best of things that lift it to a higher plane. Paloeontologists and metaphysicians with a sense of humour-if there are such-will appreciate the picture of a sabre-toothed tiger in Kent's Cavern being helped to his human dinner by a stalactite, which in so doing sacrifices its devotion to the absolute to gratify a desire for revenge on the human race. It will be seen that the author is something of a philosopher in the style of Andersen -no mean model.

ISSN:0028-0836    

DOI:10.1038/119313a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

IN reference to the expression on the part of Prof. Stanley Gardiner and others (see theTimes, Jan. 13) of a desire for the assignment of an increased grant of public money to the institution known as “the Natural History Museum” (or more correctly as“the Natural History Departments of the British Museum”), will vou allow me to say that whilst I share their wish and hope for this increased expenditure, I am strongly of opinion that no such increase should be made until the status, purpose, and organisation of this museum and other related institutions have been made the subject of a thorough and authoritative inquiry, and consequent recommendations by a Royal Commission appointed for the purpose? One or two matters which require the attention of such a commission have long occupied my thoughts, and I should like to indicate briefly what they are without entering at this moment into a discussion of details.1. The most important point for such a commission to consider is, I think, the establishment of the Natural History Departments as an independent organisation-the " Natural History Museum " or " British Museum of Natural History "-under its own Council, 'Director,' and heads of departments, receiving an adequate grant from the Treasury, and reporting directly to a Minister of State and not to the 'Trustees' of the National Library and departmental collections of ancient and medieval art and anthropology. 2. Such a commission should give an authoritative statement of the scope of the Natural History Museum with a view to its immediate organisation and its future growth and development. No such agreed statement exists. There are two distinct purposes which should (it seems to me) be made by statute equally binding on the administration of the Natural History Museum, namely, (a) the 'edification' and instruction of the public by means of exhibition of carefully chosen and prepared specimens, and (b) the safeguarding and increase of the vast series of specimens of all kinds of living things from all parts of the world which are the indispensable 'documents' by reference to, and study of, which the biological sciences acquire far-reaching importance.3. By judicious selection of the specimens to be permanently exhibited to the public with the most effective illumination and display, accompanied by skilful labelling and explanatory illustration, the actual floor-space now occupied by the public exhibits in Cromwell Road could be reduced to one-half of its present dimensions and the enjoyment afforded to the public in no way diminished. At the same time, the space thus set free could be used for the better accommodation of the reference collections and for the necessary 'work-rooms ' required by the experts who continually add to the collections and maintain them in a proper state of conservation and order. They publish (under the Museum authority) accounts of new and important additions to knowledge. These publications are made by the staff of the Museum, and also by voluntary workers whose co-operation is welcomed by the official staff. 4. I will venture no further at the present moment than to suggest in the briefest terms some developments of the activities of the Natural History Museum which a Royal Commission might be asked to consider. Thus, for example, since there is, in the judgment of leading zoologists, a need for increased accommodation and expenditure in order to give needful help to the various branches of zoological science at the Natural History Museum, one is led to inquire as to whether it is reasonable to maintain there a Department of Botany, when so splendid an institute of botany is also maintained at the public expense at Kew Gardens. I will not attempt to state either the history or the justification of the existing arrangement. But it is obvious that, were the Botanical Department removed from the Natural History Museum to Kew, a very considerable space would be available for the expansion of the other departments of the Museum. Probably somewhat complicated legislation would be necessary to bring about the completion of Kew by the fusion with it of the Botanical Department of the Natural History Museum. The question worth consideration is whether such a fusion would promote the growth of botanical science.5. A few words will serve to indicate some other developments which might be submitted to a commission. There is no truly geological museum in London. The Geological Department of the Natural History Museum has magnificent and invaluable collections of fossil vertebrates and invertebrates. But they are not there to serve the purposes of the investigator of geological phenomena. They are the records of paleontology. Many men of science would like to see a real museum of the 'geology' of the world, topographical and stratigraphical (not limited as is that of the Geological Survey), fully set out at the Natural History Museum. Another collection which has, by the chapter of accidents, been insufficiently developed at Cromwell Road is that of osteology-the skeletons of vertebrate animals. The fact that the Royal College of Surgeons has a fine series of osteological specimens has led to the relative neglect of this important branch of study by the Natural History Museum. Of late years efforts have been made to remedy this, but space, money, and time are necessary for the assemblage of such a comprehensive collection of osteological specimens as are needed by the modern zoologist, and could only be secured and preserved for reference and study by a great and wealthy museum. I may just raise another question. Should there not be within the walls of the Museum a lecturetheatre to hold some 200 visitors, where lectures and demonstrations, by means of photographs and lantern, could be given at regular intervals by the Director and lecturers called in by him ? The purpose of the lectures would be specially to illustrate and explain the contents of the public exhibition galleries. Copies of the photographs made for the lectures might be sold at the book-stall of the Museum. The lectures would deal with such subjects as " The Classification of Animals," "The Origin of Species," " Geographical and Geological Distribution," " Variation." and " Heredity." Also " Recent Ad. ditions to the Museum" should be shown to the public at regular intervals by special lectures.Lastly, as to expenditure on expeditions and collecting. The Natural History Museum has for many years given assistance to travellers and explorers by " working out " their collections, and often by purchasing specimens or whole collections. Prof. Stanley Gardiner is anxious to extend this line of activity. It is a difficult matter to deal with, since official and private interests and purposes are involved. There is an obvious way by which important new collections and special specimens may be obtained for the Museum and for the public benefit. There was in 1912 (and possibly still is) in Berlin a Society of the " Friends of Natural History." They were rich men anxious to obtain new and important specimens for the National Museum of Berlin. In 1912 they put down £10,000 and sent five hundred negroes to Tendaguru, fifty miles from the coast of German East Africa, in order to collect the bones of certain gigantic extinct dinosaurs which had been discovered there. They brought these bones successfully, carefully packed in plaister and soft wrappings, to Berlin. Their discoverer, Dr. Fraas, named the largest of these great reptiles 'Gigantosaurus.' Its femur is ten feet in length. Tendaguru is now British, and further collecting of dinosaurs' bones is being carried on by an English party. It seems to me that zoologists should endeavour to set up a society like that of the German " Friends of Natural History." Such a society exists in Great Britain for the purpose of purchasing works of art for the National Collection. The society, by offering to help in expenditure for the national collections, might (and in art matters, I believe, does) induce the authorities to make desirable purchases. Our lovers of natural history should follow the example of the Berty and of the English friends of art.

ISSN:0028-0836    

DOI:10.1038/119314a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

WITHIN the mesh of our local star-system are nebulæ of irregular shape, such as the Orion nebula, which are of only slight cosmogonic interest. Far beyond the confines of this local star-system lie the great nebulæ of regular shapes, spiral, elliptic, circular, etc., each of which is comparable in mass and size with our whole star-system. In the December (1926) issue of theAstrophysical Journal, Dr. Hubble paints a most fascinating picture of the system formed by the great nebulæ, and frames it in such convincing observational evidence that it would be difficult to reject it.As seen in a telescope, the great nebulae differ widely in shape, size, and brightness. But Dr. Hubble brings a mass of evidence to prove that differences in size and brightness between nebulhe of the same shape are almost entirely due to a distance effect. If all the nebulae were put in a row at the same distance from us, it would at once be seen that nebulae of the same shape all had approximately the same dimensions and luminosity, while even nebula of different shapes would exhibit only comparatively small ranges of dimensions and luminosity, especially the latter. This makes it possible to estimate the distances of all nebulae, even the very faintest, with fair accuracy. The faintest which can be observed photographically in the 100-inch telescope are of about 18th magnitude, and these must be at the amazing distance of about 140,000,000 light-years. Within this distance some two million nebula must lie. Dr. Hubble finds that these are fairly uniformly spaced at an average distance of about 1,800,000 light-years apart. To construct a model, take 20 tons of walnuts and space them at about 25 yards apart, thus filling a sphere of about a mile radius. This sphere is the range of vision of the 100-inch telescope; each walnut is a nebula containing matter enough for the creation of perhaps a thousand million suns like ours; each atom in each walnut is a solar system with a diameter equal to that of the earth's orbit.With minor exceptions, all the different shapes of nebulae can be arranged to form one continuous sequence, and this sequence is almost certainly evolutionary. Indeed, to my great gratification, it coincides almost identically, as Dr. Hubble remarks, with the evolutionary sequence I predicted for nebulae, on purely theoretical grounds, in 1917 (" Problems of Cosmogony "). An initial sphere of gas gives place first to an oblate spheroid, and then to a lenticular figure. After this last configuration is passed, gas streams away from the nebular equator, generally in two symmetrical streams or arms. Granulations and condensations next begin to develop in these arms, each condensation ultimately forming a separate star, until finally the whole nebula is transformed into a star-cloud. Thus the great nebula prove to be the birth-places of the stars. Long before I was able to trace out this complete evolutionary sequence, I had been able in 1901 to take a step in the reverse direction, and show that the stars had in all probability been born out of a uniform mass of tenuous gas by a process which 1 designated " gravitational instability." I calculated first that if all the matter in the present stars were uniformly spread out in space, it would form a gas of density about 1023. A dynamical investigation next showed that such a medium would be unstable, and that, as a consequence of this instability, it would break up, much as a jet of water breaks into drops, into condensations whose distances apart were a matter for calculation; on making the calculation these distances were found to be about equal to the actual average distance of the stars. Thus the single supposition that the stars had been born out of a uniformly spread mass of gas explained at one stroke the facts that the stars are of approximately equal mass, that they are spaced at approximately equal distances apart, and that these distances are what they are.Dr. Hubble now finds that the nebula also are of approximately equal mass, that they are spaced at approximately equal distances apart, and that these distances are about 1,800,000 light-years. It is natural to inquire whether these facts cannot be explained at one stroke by the supposition that the nebula themselves came to birth as condensations produced by the gravitational instability of a still earlier and more tenuous mass of uniform gas. The test of the conjecture is of course by numerical calculation. Dr. Hubble estimates that if the matter of the nebula were uniformly spread through space, it would form a medium of density 1-5 x 10-31. My theoretical formula (" Problems of Cosmogony," p. 219) show that instability would cause such a medium to form condensations at approximately equal distances of the order of 1,000,000 light-years. This is near enough to Dr. Hubble's observed distance of 1,800,000 light-years to make our conjecture seem reasonably probable.If it is accepted, we have been able, with the help of the new knowledge gained by Dr. Hubble, to trace the evolution of the universe one step farther back than has been done before. We have in succession: 1. A uniform tenuous gas of density 10-31 and of diameter at least hundreds of millions of light-years.2. Condensations developing in this gas at about a million light-years apart, and forming separate nebula with masses of the order of a thousand million suns. 3. Condensations developing in turn in the arms of these nebula, and forming stars with masses of the order of our sun. To these, if my 'Tidal Theory' of the origin of the solar system (Memoirs, R.A.S., 1917) is accepted, may be added:4. Condensations developing in the arms of gas pulled out from the stars by the tidal action of other passing stars, and forming bodies of planetary mass. 5. Condensations similarly developing in the arms of gas pulled out tidally from the planets, and forming bodies of mass comparable with the satellites of the planets.This scheme covers five complete generations of astronomical bodies, having masses of the order of 1048 (or more), 1042, 1034, 1029, 1025 gm. respectively, the birth of each generation from the preceding generation being through the agency of " gravitational instability "(Phil. Trans., 199, A (1902), p.49). It is based on verae causae, namely, the law of gravitation and the properties of the gaseous state of matter, and survives at each step the test of numerical computation and comparis

ISSN:0028-0836    

DOI:10.1038/119315a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

IN a letter to NATURE (April 17, 1926, p. 555), J. C. Slater suggested an explanation of the ‘quarter quantum numbers’ used in describing the band spectra of homopolar diatomic molecules by assuming that, on the basis of the old quantum theory, the momentum was to be integrated about a half period only, since the molecule repeats itself after a rotation of 180°. This explanation finds its natural analogy in the new wave mechanics of Schrödinger, and leads to an interesting suggestion regarding the general solution of the wave equation.In its usual form the wave mechanics presents a wave equation (H E)q, = 0, where H is an operator derivable from the Hamiltonian function and E is the energy constant. It is assumed that only such solutions of the equation have a meaning for which 4 is a regular single-valued function vanishing on the boundaries. The problem of the diatomic rotator has been solved by Schrddinger and others, who have found the following expressions for the energy and for Y where Y is that part of il depending solely on the space co-ordinates, in the present case upon the spherical co-ordinates 0 and 0, (1) E = 2=(j2+j) j-0, 1, 2, 3, (2) Y = Pi. (cos 0). (am cos mob + bn, sin m'5), m=0, 1, 2, . . . j, where PjF1. (cos 0) is the Legendre function of the mth order.To extend this solution to the case of a homopolar diatomic molecule, we have only to remember that by such we mean a molecule the two atoms of which are identical in mass and charge, that is, a molecule which repeats itself when it is rotated through 1800. In the wave mechanics this is clearly equivalent to the condition that only such solutions of the wave equation are to be accepted for which Y remains unchanged when --r 0 and 0 --ir + 5. This will be the case when j is an even integer (j = 0, 2, 4, . . .), m being as before any integer odd or even. The energy and wave function are still given by equations (1) and (2) subject only to the limitation that j shall have even integral values. It may be remarked that while we have treated the molecule as a rigid rotator, no new features are presented by taking into account the vibration of the nuclei, since such vibration does not alter the homopolar character of the system. In applying the result just obtained to the band spectra of homopolar molecules, we notice that only bands involving a change in the electronic energy will be observed, and that if these are of the usual type possessing positive and negative branches, either the initial or the final state of the molecule must be nonhomopolar. For example, if we take the excited state to be non-homopolar, we have for the energies Ei = hv, + hA'(j2 + j), j = 0, 1, 2, 3,.... Ef=hA(j2 +j), j=0, 2, 4, 6, ...The selection rule is as usualj -*5j± 1 orj --j, and the transition probabilities are given by the usual formula for dipole molecules. This leads to a set of band lines which correspond directly to those obtained previously by the use of quarter quantum numbers. While this is very satisfactory, a closer inspection shows that the theory is not in agreement with other features of the observed bands. Thus we should expect the zero branch to be given by the formula Qj = v (A A')(j2 +j), j = 0, 2, 4, . . .. whereas, for example, in the helium bands found by Curtis and Long (Proc. Roy. Soc., A, 108, p. 513, 1925) the zero branch is very accurately represented by another relation, namely: Qj =v0 (A A')(j2 +j), j = 1, 3, 5,. Furthermore, when j is allowed to have only even integral values, we obtain a specific heat curve which seems to be quite impossible, since the value of Cr/R rises to an abrupt maximum of about 1 5, thus giving a curve which in no way resembles the observed specific heat curve of H2-A way out of these difficulties may be found by employing a new postulate in the wave mechanics, namely, that, given the wave equation of Schrodinger, we shall seek such solutions to it for which the function yap, rather than if alone, shall be a regular singlevalued function where 4' is the conjugate to Wt. This assumption, which we believe has also been suggested by Heisenberg, has much to recommend itself by being more nearly in accord with the spirit of the new mechanics, since the function 4,4' seems to represent the electrical density, whereas the function 4l alone has no such physical meaning.Applying this new assumption to the homopolar molecule, we are led to two independent solutions, the first of which is equivalent to the solution already obtained. (3) j= 0, 2, 4, . AE= .2 (3)j -1 3, 5 1'E= 2 I(j2+j). These solutions, which are each complete in themselves and admit of no intercombination, seem to correspond respectively to the symmetrical and antisymmetrical solutions found by Dirac and. Heisenberg for systems composed of two or more identical parts. The empirical relations found to exist among the lines of the helium bands by Curtis and Long (I.c.) may now be shown to be just those consistent with solution (3'), although the numerical values of the moments of inertia given by them must be increased by a factor of four.S. Werner (Proc. Roy. Soc., A, I I 3, p. 107, 1926) has observed recently a band spectrum of H, in the far ultra-violet. We find that the majority of the band lines may be arranged in P, Q, and R branches the positions of which agree with the lines derived from (3') when we assume the final or unexcited state to be homopolar, an assumption which appears very satisfactory, since Werner's H2 bands evidently correspond to the Lyman series of the H atom. The band constants vary somewhat from band to band, but lead to a moment of inertia for the excited molecule of about 10 x 10-41 and for the unexcited molecule of about 6 x 10-41. The value of the moment of inertia of the excited molecule is of the same order of magnitude as the moments of inertia found from some of the bands of H2 in the visible region. Since the visible bands correspond to transitions in which both states of the molecule are excited, it is probable that in both states the molecule is non-homopolar, in which case we should continue to employ the usual formula for the diatomic molecule.Equation (3') leads to a specific heat curve for the homopolar molecule, which rises without a maximum asymptotically to the value Cr/R = 1. In the case of hydrogen the curve fits the experimental data rather well, although it rises somewhat too steeply in the region between 1500 and 2500 absolute and gives as the value of the moment of inertia of the molecule 6.7 x 10-41, in substantial agreement with the moment of inertia for the unexcited molecule found from Werner's bands. We shall nowgive briefly the results we have obtained for other rotator systems by accepting those solutions to the wave equation for which ip, is a regular singlevalued function. For the simple dipole diatomic molecule two solutions present themselves:(4) j= 0, 1, 2, 3, . E. hj2 j (4') j= g,2 , W| 72I(JJ As is well known, only the first solution (4) leads to a set of band lines in agreement with the observed band spectra of such molecules. A closer investigation seems to show, moreover, that (4') has only a formal character and could only apply to molecules for which one could exclude a priori the possibility of their ever possessing an electronic angular momentum about the figure axis. We have also considered the case of the symmetrical top molecule (i.e. a polyatomic molecule with moments of inertia A = B and C) and find that the wave equation leads to two independent solutions for which 3pb is a regular single-valued function. (5) j 0, 1, 2. . . .A .j . . . ij E(= {7+ 2 IA(j2 +j)+ (I ) n]These solutions are each complete and allow of no intercombinations, and so far as can be seen the energy of a molecule of this type might be given by either (5) or (5') but not in any case by a combination of the two. Equation (5) is exactly that already given by F. Reiche (Zeit. ftir Phys., 39, p. 444, 1926) and by R. de L. Kronig and I. I. Rabi (NATURE, Dec. 4, 1926, p. 805) for the symmetrical top molecule, on the basis that the function 4' was to be regular and single-valued. On the otd, by means of the Born-Heisenberg matrix mechanics, I have obtained two solutions to the problem which correspond exactly to the solutions given above (Phys. Rev., 28, p. 318, 1926). In the foregoing discussion of the symmetrical top molecule we have assumed that 4'4' will remain unchanged for a rotation of the molecule of 3600 about the figure axis as well as for a complete rotation about the precision axis.If, however, the molecule has a symmetry element in the position of its particles, we must introduce further conditions. For a molecule which repeats itself after a rotation of 27r/k about the figure axis we find the two independent solutions, (6) {I=0, 1, 2, j = J, i, i (6') k 3k 5k .E = 8 1( j2 +ji) +(C-)8 where the absolute value of n is less than or equal to j in both cases. It is with great pleasure that I thank Prof. E. Schrodinger for many suggestions and for many helpful criticisms during the course of the work. I hope to publish in the near future a more detailed paper covering the calculations.

ISSN:0028-0836    

DOI:10.1038/119316a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

J. A. FLEMING (Proc. Phys. Soc. Lond., 26, 318–333, 1914) reached the conclusion that the variation with height of the dielectric constant of the atmosphere would bend a ray sent out tangentially to the earth's surface so that its radius of curvature would be about four times that of the earth. Furthermore, he found that, if the atmosphere were constituted wholly of krypton, a horizontal ray would have a radius of curvature equal to that of the earth, on account of its greater density.As the radius of curvature in air is comparable with that of the earth, we thought it possible that the angle of incidence of the wave on the Heaviside layer would be so affected as to make the apparent height of the layer too great. Although we find this effect to be quite negligible, we came across a point which may be of interest-namely, if electromagnetic waves sent upwards are to return, the effective value of the dielectric constant must change with height in a definite manner. From recent investigations it appears that from 40 km. to 150 km. above the earth's surface the temperature rises from 2200 A. to 3000 A. We assume that this change is linear and that the constitution of the atmosphere remains unchanged. These two assumptions, combined with the values of density and height tabulated on p. 72 of Humphreys' " Physics of the Air," give to a fair approximation the following empirical law connecting density d and height h in kilometres: d=0.0013e-O014h. The well-known relation between dielectric constant K and density, that (K 1)/(K + 2)Gc d, combined with the equation for d, gives the empirical relation K = Ko + pe -a, from which the value of p is 0-59 x 10-s, taking a = 014, and K.= 1. Considering the earth as plane, it can easily be shown that a ray starting from the earth's surface at an angle of elevation 95, will become horizontal at a height y given by ay = loge [(p Cos2 p0 sin2 40)/p]. This cannot hold unless tan2 0, p, whatever may be the value of a. This means, in the case of the earth, that a ray starting at an angle of elevation of more than 10.5 cannot return to the earth if the above law for K holds. If, on the other hand, the signs of both p and a are changed, rays at any angle would eventually return. The equation, when we take account of the earth's curvature, is cos O/ cos o0 = R[l + (1e-aY)p/2]/(R+y), where 0 is the angle of elevation of the ray at any point, y the distance of the point from the surface, and R the radius of the earth. When the ray is parallel to the earth's surface 0 = 0. Therefore sin f= 1 +y/R -(Ie-aY)p/2. From this equation conclusions can be drawn similar to those obtained above when considering the earth's surface as plane. We thus arrive at the result that the general condition under which a ray can return from the upper atmosphere is that the second differential of the dielectric constant with regard to height should be negative. In the case of the earth's atmosphere the density, according to the assumption given above, varies in such a manner that this differential is positive. The conclusion does not hold for rays at angles of elevation of less than 10 or 2

ISSN:0028-0836    

DOI:10.1038/119317a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature