摘要:

THE British Association is not the only organisa. tion in Great Britain having for its avowed object the advancement of service. Every learned society, all the va odies dealing with the professional s of scientific and technical workers, ar whole herted devoted to the same cause. But the British Assciation has very special functions in addi to those of giving a stronger impulse and a more systematic direction to scientific inquiry and promoting the intercourse of those who cultivate science. It was also called into being to obtain more general attention for the objects of science, for which purpose it set itself the task of familiarising the general public with the progress of scientific research and developing a consciousness of the effects of such research upon man's material and intellectual progress. Such activities are essentially complementary to those of the learned societies, the function of which it is to provide specialists with the necessary facilities for meeting others engaged in the same particular branch of science, and for the appraisement and publication of their work. Specialisation in science is inevitable. It is indeed doubtful whether the present division of the scientific members of the British Association into sections and sub-sections corresponding with the principal branches of science is adequate to their needs. Thus, the exponents of a growing and most important branch of science like bio-chemistry may find the time quite insufficient which is allotted to them in the chemistry section, or in joint meetings of that with other sections. Again, those engaged in aeronautical research may feel that neither the Section of Mathematical and Physical Sciences nor that of Engineering gives their field of inquiry the consideration it deserves. It would occasion no surprise, therefore, if further subdivisions were made in the near future.It is perfectly clear that the more specialisation there is in science the more need there is for the Council of the Association to exercise the greatest care and vigilance to prevent the obscuration of its main object. Even for scientific workers there are special advantages attached to membership of the Association. At each yearly meeting they are provided with unrivalled opportunities for meeting with others drawn from all parts of the world and discussing their work, for surveying the progress made in their respective branches of science and for becoming acquainted with the advances made in practically every other field of scientific endeavour. In return for these very real privileges gained for them by the growing prestige of the Association, they could and should be expected to pay more regard to the desire of the lay members who attend its meetings, and the general public which reads the reports, for the presentation of the advancement of science in language intelligible to the non-specialist.It must be remembered that the British Association is not purely a professional body like the British Medical Association, Iron and Steel Institute, Institution of Naval Architects, and similar organisations which hold meetings at different centres year by year. It invites the general public to become members, and many of them do so at every place where a meeting is held. If the Association were a closed corporation of workers in pure and applied science which met to discuss the position and progress of particular branches of natural knowledge, the character of the proceedings would be its own affair. As, however, a fairly large proportion of its annual members belong to the lay public, it owes a debt to them as well as to the scientific members; and we doubt whether this duty is fully met by the provision of the Citizens' Lectures, though the lecture on "Energy" delivered by Sir Oliver Lodge at Leeds was a brilliant example of what can be accomplished in this direction. We suggest that each section might appropriately devote at least one afternoon meeting to a lecture or discussion of what may be conveniently described as a Royal Institution type, that is, intended for intelligent people who are interested in advances of science and yet are not actual workers in the particular department to which the subject refers. It would be found that there are many scientific workers who would be glad to attend such accounts of progress in fields outside their own, in addition to members of the general public who join the Association in the hope of obtaining such enlightenment. As to the presidential addresses, however specialised may be the field of research of any president of a section, upon him or her rests the responsibility not only of relating special studies with one particular branch of science, but also of making every effort to establish contacts with other fields of scientific inquiry and to demonstrate the essential unity of purpose of them all. This responsibility can be shouldered neither by the General Committee nor by the Council. But the Council of the Association obviously has the right to expect that organising committees will assist in preventing the annual meeting from developing into summer vacation meetings of a number of learned societies.If any one doubts that there is a growing tendency in this direction, let him examine the subjects chosen by authors and the summaries supplied for inclusion in the journal of transactions of the Association for the past few years. Some of the subjects are so specialised in scope that it is improbable they could have been of interest to more than a few members of the particular section to which they were delivered. Many of the summaries are couched in such highly technical language that even the special scientific correspondents of the great newspapers find them unintelligible. There would be little occasion for lengthy comment were it only the youthful aspirants for scientific honours against whom this charge of obscurity could be brought. We could rely upon time to purge them of the conceit of demonstrating familiarity with their newly acquired forms of expression in order to win a reputation for erudition. Unfortunately, some of the addresses delivered by sectional presidents at Leeds displayed the same weakness, From the point of view of title, subject matter, and form of presentation, they were alike calculated to produce in many members of the Association a feeling of bewilderment. We do not doubt that these addresses are noteworthy contributions to the problems of particular fields of work, but as they are printed we suggest that they need not be read in the section rooms, or at any rate only those parts which can be followed intelligently by the section as a whole. There may still be some members of the general community whose respect for science is in inverse proportion to their capacity for understanding what is presented to them; but they are a dying race. Thanks to the reforms brought about in our national system of education since the beginning of the century, there is a large and ever- increasing army of people equipped with enough knowledge of science to be hungry for more. The publication and large sales of certain popular handbooks on scientific subjects is a clear indication of this interest in the activities of our research workers.The members of the general public who attended the Leeds meeting are in a position to judge of the quality of the communications presented as addresses and papers. Those who perforce had to rely on newspaper accounts of the proceedings will be mystified by the paucity of the references to those subjects which they regard as the exclusive domain of the scientific worker. While this can partly be attributed to the contempt which some reporters and editors have for the level of intelligence of their readers, most of the fault lies with the authors of papers. They are prone to ignore the fact that with so wide a range of choice of subject matter for Qopy, the press representatives will invariably seize upon that which is presented with such clarity as to dispense with the need for interpretation. For this reason the sections dealing with education, agriculture, and economics receive more than their proportionate share of attention in the newspapers.It may be urged that certain subjects cannot be presented in a form calculated to appeal to a wide public. If that be the case, they should either not find place in the proceedings of the British Association, or alternatively, the papers given at the annualmeeting should be divided into two categories, those which are intended to appeal to a wide public and those which are for the exclusive benefit of specialists. It is inconceivable that in any of the branches of science represented by the thirteen sections there should not be sufficient material each year upon which to base an address to nonspecialists; and presidents of sections, as well as other authors of papers, would be well advised to prepare summaries of the main features of their addresses for advance distribution to the press. They can rest assured that unless they can first interest the newspaper reporters they will have little opportunity of interesting the public in their work. They need not fear, moreover, that a reporter will rest content with a summary. A test of good journalism is the originality with which a subject is treated. Given a summary as a setting, the reporter will find jewels with which to adorn it. The advancement of science depends upon the encouragement of research. The public must be better informed if it is to appreciate to the full the need for more and more research. It will not willingly endow what it cannot understand. Let scientific workers who attend the yearly meetings of the Association ask themselves why, in its wisdom, the Council holds each meeting in a different centre of population in the country. Presumably it is done for its propaganda effect. Bringing scientific workers into personal relationship with various sections of the community helps to destroy the illusion that we are a race apart. Clear exposition of science should also dispel the idea that scientific experiment is mere legerdemain, its mysticism heightened by a rigmarole of complex terminology. Explicit statement is the necessary precursor of wide publicity, without which there cannot be general appreciation of the aims and methods of science, of what science has achieved and what it might achieve for the human race.

ISSN:0028-0836    

DOI:10.1038/120501a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

NOTHING is so significant of the power of the old classical traditions the extent to which the literature of fiction remains comparatively unmoved under t e s ock of scientific discovery. For the intellectual revolutions which have, been effected during this past century by a mere handful of blandly inquiring scientists can be matched only by the socialand industrialtransformations to which they have unconsciously contributed in no small measure. To a scientist a new field of human experience and expression is opened up. He sees life unfolding, not merely as the old interplay of human emotion and passion, but rather in response to the widening environment developed by man's increasing knowledge. In the field of science, for him who has eyes to see, dramatic material is not far to seek, but current fiction remains singularly aloof. Here and there a detective, a pathologist, or a medical practitioner is created who plays his part against a suggestive background of mysterious knowledge, but there is no novelist, with the exception of Mr. H. 0. Wells, in whom the dramatic element in scientific discovery evokes a sufficient response to urge him to action.The strong human impulses associated with love and sex which have formed the keynote of so much of modern fiction are not absent in the work of Wells far from it but the psychological behaviour of the scientist, his interests, his urges, the material he handles, and the stage he treads, constitute a region into which none other than Wells has dared to enter. Coming to literary work from the field of technical knowledge, Wells has made the amazing discovery that a scientific training, far from being a handicap, is a positive blessing. A good novelist, if he is anything, is pre-eminently a psychologist. It is his function, by means of the technique of storytelling, to observe, to describe, and to analyse the thoughts nd actions of mankind, and not merely that aspect of mankind constant throughout time, but mankind in the making. He stands at the point of vantage who absorbs with understanding the newer knowledge. Being artistic, such an analysis in the creation of a novel it is really a synthesis is not scientifically systematic. It differs from a study of a scientific problem in this respect, that no two novelists in their treatment will produce the same result. The final product is dependent on the mentality of the solver. Thus the psychological study developed by the novelist is, as often as not, a reflected study of the author. Wells stands at this point of vantage; and in describing his vision opens up his mind.Here, then, in the present group of short stories, we see Wells, a young imaginative artist, striding boldly into the field and with a few strokes creating a world which hums strangely in the ears of the old classical school. Tuned to the mentality of the scientist and alive to the trend of scientific thought, Wells enters the arena of fiction armed with weapons denied to his professional colleagues. He may manoeuvre in regions of the arena with assurance where others must hesitate to tread, and the earlier stories in this extraordinary collection show Wells disporting himself gaily and masterfully among the fantastic notions born of much of the speculative science of the late Victorian era. Early hesitant knowledge of time and space are handled with assurance and imagination in "Th Time Machine," "The Plattner Story," "The Strange Case of Davidson's Eyes." Sometimes his boldness is preposterous, as when in My First Aeroplane he makes a machine in 1912 stand up to treatment that no self-respecting aeroplane in 1927 would possibly tolerate without destruction. At other times it is almost prophetic, as in The Land Ironclads, where in 1903 trench warfare and tanks are described in unerring detail. Again and again he traces the emergence of a world of wheels, and shafts, and furnaces.It is easy to say that, in those early days of Wells's literary work, the young man is merely tickling the palate of the reader with a series of extravagant ideas. While it is probably true that a number of these stories are scarcely more than this, there recurs continually the suggestion that if mankind would only realise it, the potentialities for good and evil in modern scientific discovery on the mechanical side are enormous. There is, for example, A Dream of Armageddon, A Story of the Days to Come, and so on. There appears the implication to the scientific man that he must give himself pause to consider whither his newer knowledge may drive mankind, and to the layman the startling question as to whether he is indeed ready to receive this strange knowledge. The theme changes slightly as Wells borrows from his biological experience. The power of natural selection as a factor in evolution is violently forced to our notice here and there. In The Country of the Blind, the capacity of the human organism to adapt itself to environment, and the extent to which refinement in the senses may proceed in response to needs, are brought out with the skill of a master. The Empire of the Ants teaches how survival of the fittest is by no means identical with survival of the most desirable. In The Time Machine we are projected forward into futurity and are horrified to discover that mankind has long passed the zenith of its highest development and a kind of retrogression or involution has set in, in place of the higher evolution.These ideas may be fantastic; they may be mere examples of mental agility and imaginative strokes of a young man in a field yet unopened to assured knowledge. But we begin to perceive that in the background of Wells's mind there exists a dominating urge. Mankind itself raises a problem of colossal magnitude how to utilise the accumulating wealth of scientific knowledge in the design of a super-race- -of a civilisation devoid of the stupidities and absurdities of social life as we know it. These stories where they touch this issue scarcely do more than raise it. Some indication of Wells's own line of approach to this difficult issue is provided by glimmerings of Utopias of various kinds that sparkle out here and there. It is in his larger and more mature works that these ideas are worked out in greater detail, but, on the whole, Wells on the constructive side is much less satisfying than at his favourite game of thought provoking. Utopias are literally as old as Adam, but it is permissible to doubt whether the mental exercise in their design ranks higher than that used in the solution of a crossword puzzle.It is possible that in a sense they may serve the useful function of preparing the minds of some for the possibilities that might be achieved, for the ideals to which to strive. But imaginative gropings in a dim future, with roseate pictures of the dawn of a new era when man will grasp the forces of Nature in the hollow of his hand, will not provide a solution of the immediately pressing problems of production, distribution, and exchange; for the question uppermost in every one's mind, both scientist and layman, is, What to do now? The kind of promise the imaginative Wells has held out in these early stories is not fulfilled by him in his later work. Doubtless, had his numerous love novels been left unwritten, the world of literature would have been enormously the poorer, but the far-reaching and vital questions which Wells himself raised have really not been faced by him. Instead, he has left it to the politicians, content to be a mere finger-post pointing towards an inaccessible region of the horizon.

ISSN:0028-0836    

DOI:10.1038/120503a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

T will be generally recognised that the formation and laying-out of highways and crossroads have, until recent years, been far more in the nature of a science than an art, though art has begun to enter into its kingdom since the passing of John Burns?s Town Planning Act, the first of the kind in the British Isles. Not that with the advent of art into the matter of road-making science will function to any less degree. For though it is not every one who holds the view that science must of necessity retrograde in the absende of advancing, yet it is certain that modern progress in regard to the modes of travel must carry ?in its train scientific progress. When any one takes thought of road-making, the memory of what the Romans accomplished in this direction is inevitably to the fore. Without staying to consider such local routes as they constructed in the City of the Seven Hills and other places of importance, it will suffice to recall those great military highways which so aided them in the control of their vast empire. England still possesses portions of these notable enterprises?as witness Watling and Stane Streets and others? which radiated from London (the Augusta of Roman days) throwing out their tentacles in various directions.These Roman roads were, however, undoubtedly purely military and scientific; military in their nature and purpose, and scientific in their construction; art could claim no part in them. In the magnificence of Roman conception a military road was driven from centre to circumference with as close an approximation to a radial line as could be achieved; natural obstacles were for the most part overcome by means of bridges and tunnels, according to the gradients encountered. Mansiones or camps were established en route, though is the customary Latin word for ?camp? which has survived to this day in the nomenclature of so many of our towns. The Roman roads were made to endure, like the Egyptian monuments of earlier date. It is only as the nature of the passing traffic alters and its volume incre3ses almost beyond conception, that other routes, other methods and other construction, have had to supersede a system of incomparable virtue.Perhaps it is giving too great credit to the British character to attribute the passing of the Roman highway to the necessities of the twentieth century; for the truth is, that long before its advent, British insouciance had consigned the memory of these military trophies to the limbo of neglect, if not, indeed, of oblivion. The Roman thoroughfares were constructed on good scientific principles; a firm bottoming was obtained by ramming small stones and bats of brick into the ground, and on this foundation was laid a pavement of large stones accurately fitted like a mosaic pattern, the interstices being carefully jointed in cement. Where large stones were unobtainable, then a species of concrete was substituted, composed of small hard stones bound together with lime.Of course, these main highways accounted only for a mere fractional part of the means of transit necessary throughout Great l3ritain. Here British sluggishness of temperament asserted itself unalloyed. A mere path, sufficiently wide to enable a pack-horse to bear its burden, would gradually form itself, rather than be formed, in the required direction; even then it would not go straightforward, but would meander between and around the trees, thus in time providing us with those serpentine courses, which have a charm to the eye, even though regarded as practically undesirable. These tracks invariably followed the line of least resistance; the fordable part of a stream would be approached, whatever deviations might thereby be rendered necessary. Thus these initially unobtrusive paths gradually became beaten tracks, widening sufficiently in time to admit of the passage of carriages meeting en route, though frequently even this was not accomplished. But as for any scientific construction, it can but be said that science was conspicuous by its absence. If Irish main roads were passably good (for the period), English were passably bad, whilst Scotch (according to a countryman?s evidence, namely, Macadam) were atrociously bad.In England the main idea, so late as the early years of the nineteenth century, seemed to be to barrel the roadway by arching it almost inconceivably high at the crown, with a very steep gradient to either flank. When the inevitable occurred, and the road became rutted as in a nightmare, the curative process consisted in filling up the ruts and making the crown usable by means of vegetable debris, loose stones, and general rubbish, all brought to a sufficiently smooth condition, so as to receive the cachet of the local authority (such as it was), and then?all would be da capo. This period of darkness endured until about a century ago, at which time the enlightened labours of Telford, Macadam and others served to bring about such improvements as paved the way for modern scientific production. There are many who still regard the method developed by Macadam as of value, even under the changed conditions of the traffic problem?mechanical transport, heavy in its nature and dense in its massing, convulsive in its movements and rapid in its passage. But science, ever on the alert, introduces new solutions to meet altered conditions, and so we find macadamised roads giving place to the use of granite setts, concrete, wood blocks, rubber surfacing, asphalt paving, and, most interesting perhaps of all, the reinforced concrete treatment of the substructure.The progress of science makes welcome the production of literature dealing with the subject of road-making, and the two books under notice would seem to be one the corollary of the other, or perhaps they should be regarded as mutually interdependent. Messrs. Green and Ridley consider the subject from its scientific basis, dealing successively with hydrocarbons, bitumens, asphalt, sand, tar and pitch, cement and concrete. The first chapter dealing with molecular structure and valency is peculiarly interesting, perhaps more so than many that follow. The authors have a high opinion of asphalt for the surfacing, and certainly it seems to take rank after macadam from the viewpoint of anti-slipperiness. The authors do well to state that the reliance too often placed on maintenance guarantees by road surveyors is causing the substitution of a cheaper material, to the possible detriment of asphalt paving in general.? Regarding the suitable-mixture diagram shown on page 49, there seems to be a lack of agreement with the text on the previous page; for the diagram apparently indicates the medium group as giving 12-50 per cent, and the fine group, 30-60 per cent., whereas the text reverses these figures.It is properly remarked, that ?in taking a sample of sand for the mechanical analyses or grade composition, care should be taken to secure same from the inside of the heap?; and the recommendation of tar maadam surface for motor traffic is well advised. But why should such solicitude be expressed on page 71 for fish, respecting the use of tar The practical consideration of construction is developed in Mr. Harrison?s book in a very interesting and masterly manner, and the business aspect is thoroughly regarded. Indeed, the main adverse criticism to be offered arises from the inadequacy of many of the half-tone illustrations, which often ned the base reference to produce intelligibility. It is a fact also, that some people might think that there is too great a fetish made of timekeeping to a second, but this meticulousness is recommended in the interests of the contractor. It is not possible to agree with the author (see page 184) that the table in fig. 7 shows a large percentage of time lost due to water trouble, though such loss is made manifest in the next figure. The series of sixteen chapters is well worked out, and the graphs and diagrams in general are clear. It is not to be disputed that (within certain limits) the greater the method which can be introduced into a contract the more it makes for final satisfaction. This was eloquently manifested recently in the erection in Piccadilly of the new Devonshire House, which was worked out upon a schedule prepared by its American architect on lines of exactitude, such as Mr. Harrison recommends in his book on concrete highway construction.

ISSN:0028-0836    

DOI:10.1038/120505a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

(1) THE last thirty years have witnessed the inauguration of a new era in the study of mental phenomena, the introduction of the discipline of scientific induction into a field of inquiry in which the deductive procedures of the scholastic method had run riot for many centuries. The study of the evolution of the nervous system and the experimental investigation of its mode of working prepared the way for the understanding of the biological processes that express themselves as mental phenomena. Such researches as are associated with the names of Sherrington and Pavlov are clearly of fundamental importance for the interpretation of the working of the mind and for correcting the assumptions of introspective psychology. Armed with the results and the methods of experimental physiology, the psychologist has devised tests of his own to apply the method of experiment to the phenomena of mind and, under theleadership of Spearman, has attempted to express in mathematical form the fundamental analysis of mental ability so that it can be measured and subjected to the test of experiment. Perhaps the most fruitful field of psychological inquiry has been provided, however, by the clinical study of the mental effects produced by injuries to the nervous system in particular the vast experiments provided by bullet wounds in the War. Moreover, the anxiety states created by the abnormal stress and strain of trench warfare, and the moral and intellectual damage resulting from encephalitis lethargica since the War, have shed important light upon the emotional side of the mind's working. It is no exaggeration to claim that these three departments of clinical study have provided a new revelation of the dependence of mental and emotional expressions upon neural mechanisms. In the technical medical journals a vast amount has been written upon these subjects: in his great monographs on sensation and aphasia, Head has given his interpretation of the mental significance of nervous phenomena: many other books have been published dealing with the expression of the emotions and the psychological significance of the activities of the brain: but it remained for some psychologist to expound in generally comprehensible terms the new light shed upon the workings of the mind by recent research in clinical medicine.This difficult task has been attempted by Prof. Henri Piron, of the College de France. He has subjected to a critical but sympathetic examination the medical reports on the results of injury to brain and nerves, and has succeeded in giving a fair and reasoned analysis of the results achieved.It is particularly interesting to find a French author expounding so lucidly Head's researches on sensation and aphasia. Though his acceptance of Head's views is qualified, he has given his readers an unbiassed account of the methods and results and a generous appreciation of their significance to psychologists. His discussion of aphasia is particularly instructive. Summing up the history of research into the significance of speech-defects resulting from injuries to the brain, he gives a clear and just estimate of the contributions of Gall, Broca, Bastian, Charcot, Wernicke, and Pierre Marie; he concludes: At present, in an atmosphere of thought impregnated with Bergson's powerful critique, so quickly assimilated that it has become impersonal, it is the intellectual analysis of the function of language, such as that attempted by Head, which has come to the front, and we are returning to the profound views of Hughlings Jackson, which were obscured by the brilliance and prestige of Charcot. This frank admission is distinctive of the fairness and impartiality of the author. In translating this look into idiomatic English, Mr. Ogden has successfully accomplished a task of no mean difficulty. But it is unfortunate that he did not submit the proofs to an anatomist: for several of the technical terms, though literally translated, have emerged in curious forms. Thus the intracortical fibres known as the stria of Gennari, often referred to by French anatomists as the band o4 Vicq-d'Azyr, are called in this book (p. 254) the bundle of Vicq-d'Azyr, which is the name of a very different kind of structure in another part of the brain. The figures also contain many inaccuracies in particular Fig. 2 on p. 6. Special mention is made of these defects, because this book is one that will be particularly useful to the medical student; and some teachers might hesitate to recommend a work containing such lapses. In a new edition it would be wise to provide an entirely new set of illustrations. For the book deserves better treatment in this respect.(2) The book by P. and W. R. Bousfield is a speculation that attempts to give concreteness to McDougall's conception of a psychical structure as part of the mechanism of mind. Thus theauthors claim that they have endeavoured to expand this more or less metaphorical conception by the hypothesis of a real psychic structure which is an essential part of the organism. This search for an elusive mind-stuff seems to have been prompted chiefly by McDougall's claims that the progress of our knowledge of the brain has shown conclusively that there exists no one part in which all sensory paths converge and which might be regarded as a sensoriimcommune and further, that there exists in the brain no such physical medium of composition, and that the processes of the several sensory nerves simultaneously excited do not affect any common material medium to produce in it a complex physical resultant (p. 18).More than a quarter of a century ago I invented the term neopallium' for the definite cortical area where all sensory paths do converge and pour their currents into a continuous sheet of grey matter, which is a most definite and indubitable physical medium of composition.' Hence I am unable to accept the basal assumption of this book.

ISSN:0028-0836    

DOI:10.1038/120506a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THE position of the genus Citrus amongst fruit - crops cannot be over-estimated, for it includes fruits of such general use as the orange,lemon, lime, and grape-fruit, with others of less economic importance. This being the case,comprehensive books upon the subject are necessary from time to time, in order that growersin the many countries where these fruits are cultivatedinformed of improved varieties and better methods of cultivation and marketing as they are evolved. All these points and others are dealt with in the work under notice; in fact the scope of the book is scarcely described by the title, for although good many pages deal with the cultivation of Citrus fruits in a concise and altogether excellent manner, historical, botanical, and marketing problems are dealt with quite as succinctly.Although the author only sets out to describe the position that Citrus fruits hold in the United States of America, he gives a fund of information that will be found to be of value to growers in other parts of the world. Commencing with chapter on the ?Commercial Importance of Citrus Fruits,? the author indicates by tables the growth of the industry in Florida and California from the years 1886?87 to 1923?24 inclusive. His records are taken from the number of boxes of fruit handled by the railway companies during that period, and it is illuminating to learn that whereas in 1886?87 1,260,000 boxes were despatched from Florida and 840,560 from California, in 1923?24 Florida sent away 20,399,614 boxes and California 24,292,800 boxes. In the chapter dealing with the botany of the Citrus fruits, the author gives descriptions not only of the species bearing marketable fruit but also of allied species and the few interesting hybrids that have been raised. He takes a limited view of both genera and species. The trifoliateleaved section, for example, that is so well represented by Citrus trifoliata Linn., he places under the generic name of Poncirus, whereas the Kumquat group appears under Fortunella. He also limits the range of the species retained in Citrus. Thus the lemon appears as C. meclica Linn., the lime as C. aurantifolia Swingle, the shaddock as 0. maxima Merrill, the pomelo or grapefruit as 0. paradisi Macf., the sour or Seville orange as C. Aurantium Linn., and the sweet orange as C. sinensis Osbeck. The cultivated groups of Citrus fruits are then divided up and the varieties cultivated in America are dealt with. Some 49 varieties of sweet orange are described under the sub-heads Spanish oranges, Mediterranean oranges, blood oranges, naval oranges. Sixteen varieties of pomelo or grape-fruit are described, withnumerous limes and lemons. The cultural part of the book deals with all operations from propagation and planting to the care of the mature trees. Manuring, treatment of diseases, pruning, collecting the crop, and many other aspects are discussed. Handling the crop and marketing is also a very useful section. The author is to be congratulated upon the production of a very complete and useful book.

ISSN:0028-0836    

DOI:10.1038/120508b0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

Prof. FORSYTH'S latest work appears opportunely at a time when there is quite a notable revival of interest in the calculus of variations. To those who desire an account of the subject which, while modern, sound, and practical, is free from the extreme rigour so popular in certain quarters, this volume will be most welcome. The first chapter contains a discussion of the early investigations associated with the names of Euler, Legendre, and Jacobi. Here the discarding of the irritating (3-notation originally introduced by Lagrange has greatly clarified the exposition. In the second chapter an account is given of Weierstrass's modifications of the analysis when both the independent and the dependent variable are subjected to variations. The four following chapters deal with extensions to the cases in which the integrals involve derivatives of higher orderthan the first and more than one dependent variable.Up to this point the variations considered are of such a nature that one smooth characteristic curve is deformed into a neighbouring smooth curve. Such variations are described as weak' variations. In order to obtain complete solutions of the problems of the calculus of variations, it is necessary to consider the possibility of small ˜jagged or strong variations. The discussion of such variations has shown that, while the tests employed in the older analysis are necessary, they are by no means sufficient; and, indeed, it has been found that some of the most important results believed to have been established by the older methods are no longer valid. Weierstrass investigated one simple type of these strong' variations, and an account of his work, and of his E-function, is given in chapter vii. The eighth chapter deals with relative maxima and minima of single integrals, and the remaining four chapters contain extensions to double and triple integrals, the analysis in these naturally becoming more complicated. Throughout the book there are numerous examples fully worked out.Though the calculus of variations has been studied spasmodically for some two hundred years,its development has scarcely yet reached a stage at which it would be possible to write a compact account of the subject suitable for use as a college text-book; but, to original workers, this treatise should prove both useful and stimulating

ISSN:0028-0836    

DOI:10.1038/120509a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THE experiments of Kirchner (Ann. d. Phy.,4, 77; 1925) and of Gill and Donaldson (Phil. Mag.,2, 129) have shown that a tube, pumped down to what is usually termed a non-conducting vacuum, will give a brilliant discharge if excited at comparatively low voltage at a frequency corresponding to a six- or seven-metre wave, the current being fed to the tube through external electrodes of tin-foil. During the past summer we have made a further study of the phenomena exhibited by these high-vacuum tubes, with especial reference to thespectra of the discharge.The tubes were first given a drastic cleaning with caustic potash, alcohol, chromic acid, and distilled water They were then dried and exhausted with Hoiweck molecular pump, the walls being heated repeatedly (luring the process. A tube provided with internal electrodes, in the pump circuit, showed no discharge when connected to an induction coil giving a two-inch spark. We then excited the tube provided with electrodes of tin-foil with an oscillating circuit giving a three-metre wave. A brilliant blue discharge at once appeared (hydrogen spectrum), the general appearance of which would have led one to believe that the pressure must be of the order of a millimetre. Discharges under the above conditions are attributed, by their discoverers, to a to-and-fro oscillation of the electrons, the time of transit down the tube being less than the time of the half oscillation of the electrical circuit.We found that, if the pump was kept in action while the tube was excited, the blue hydrogenspectrum gradually ?disappeared, being replaced by the olive - green discharge characteristic of pure oxygen, while the tube walls phosphoresced with a very brilliant ruby-red light.A photograph of the spectrum showed the line and band spectra of oxygen, together with manycarbon lines, the pair of double lines in the region X2850 being especially prominent. On continuing the pumping and excitation for an hour the oxygen spectrum faded away, followed by the carbon lines, until only the double pair remained, at least with moderate exposures.The red phosphorescence was present with tubes of soft glass, pyrex glass, and fused quartz. A similar red phosphorescence has been noticed by one of us during an investigation of the hydrogen spectrum, with a very long tube, brought to the ?white-stage? (that is, with the walls thoroughly dehydrated by long operation with a heavy current and continuous pumping). On exhausting to a high vacuum and admitting a little oxygen, the walls phosphoresced with a pink colour under the influence of the discharge.Later in the summer, one of us made some further experiments with one of these tubes in collaboration with Prof. T. R. Merton at his private laboratory. The tube had been sealed from the pump in Tuxedo, and as a result of continued operation showed the red phosphorescence but feebly when excited by an oscillation of a seven-metre wave-length. On substituting an oscillator giving a thirty-metre wave we obtained a fairly strong red glow on the walls. Using one electrode only, we found that a magnet, brought close to the walls, caused a concentration of the red glow on the near side of the tube, the deflexion of whatever caused the phosphorescence of the glass indicating negative electrons moving away from the electrode. At the other end of the tube, the magnet repelled whatever caused the glow to the further wall of the tube, indicating electrons moving towards the electrode. We believe that phosphorescence is associated in some way with the presence of positive ions of oxygen, but the exact mechanism of its production has not been ascertained. An investigation of the inner wall of the tube by polarised light, to detect possible changes in the surface layer of the glass, will be made in the near future, for it seems probable that the oxygen is derived from the silicon oxide. The carbon undoubtedly is due to vapour from stop-cock grease.

ISSN:0028-0836    

DOI:10.1038/120510a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

IN the leading article in NATURE of Sept. 17 in relation to the imperial Agricultural Conference, it is pointed out that in some branches of science there is “a lamentable deficiency” of young men coming forward to take up research. Special reference is made to research in genetics, but the statement applies to most branches of applied biology. Whilst such positions as are available in the British Isles are eagerly sought, those in tropical colonies, and to a less extent in the Dominions, are not generally attractive to university graduates in biology.It appears to me that the main reasons for this state of affairs are: first, that biologists in such posts are largely isolated and lose touch with progress their science; and, secondly, that once they have embarked on such a career they have little prospect of returning to a good position at home. This second reason is obviously partly due to the first, but it largely also due to the fact that men in the Dominions and Colonies rarely get the chance of applying for the vacancies that occur in the British Isles. Such vacancies are usually advertised in the leading English papers and in NATURE, but by the time these papers reach readers in the more distant Colonies and Dominions, the date for sending in applications has usually passed. For example, forty-four posts of various kinds the British Isles were advertised in NATURE in July and August this year. I find that the average length of time from the first appearance of the advertisement to the latest date for receiving applications was twenty-one days. The period varied from three to fifty-nine days, but in only ten of the forty-four was it greater than four weeks. It seems obvious that most of those responsible for fixing the terms application for scientific posts in Great Britain have not yet learnt to think imperially.Positions in Government departments and official institutions in the Dominions are generally only advertised locally. For example, in two of the Australian States the position of Government Entomologist recently became vacant, and in each case was filled after advertisement only in Australian papers. Probably there were numerous entomologists in India and the tropical Colonies who would have applied for these positions if they had had the opportunity. The recent Colonial Conference recommended the formation of a Colonial Agricultural Research Service directed bya Council, one of the functions of which would be ?the organisation of a ?pooi? of scientific workers.?The pooi would probably be more attractive to such workers if a channel is constructed from it leading to positions in the home country and the Dominions.Experience in the tropics has obvious attractions for young biologists, but after a time they naturally look for positions in temperate climates where they can make homes and bring up their families. The proposed Council might perhaps act for members the research service in the same way as the employ ment bureaux of our universities act for their graduates, by helping them to find suchpositions.The disadvantage to the Colonial Service which would result from the loss of more of its best workers would probably be more than compensated by the increased attractiveness of the Service which would result from such a policy, and the Empire as a whole would certainly benefit by it. At the present time, when official appointments are made, preference is given to candidates with records of service in the War. In future, perhaps we may see advertisements announcing that preference will be given to candidates who have served in other parts of the Empire.The Colonial Conference also recommended that the proposed Council should act ts ?a clearing house for information.? The problems of the Empire are similar to those of other parts of the world, so that the necessity of a special imperial bureau of information seems scarcely apparent in view of the existence of the International Institute of Agriculture, which is ?a clearing house for information? for the world. At the present time the number of research workers in the British Empire who regularly see. the abstracts prepared by the International Institute is probably only a very small proportion of the whole. They should surely be supplied to every agricultural research station. At present they are generally to be found only in the central libraries in the capital cities. Abstracts are of course chiefly valuable to a research worker as a guide to publications bearing on the problems which he is investigating. Some organisation for supplying him with copies of the papers he desires to consult would be of great benefit to the isolated worker, who cannot afford to subscribe to a large number of journals on the chance of seeing papers of interest to him. An Imperial organisation for this purpose should surely receive the support of all the Governments of the Emp

ISSN:0028-0836    

DOI:10.1038/120512b0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

SOME months ago a large elm tree (Ulmus campestris) growing on the grounds of this station was blown down. When it was being sawn into blocks recently an interesting structure was observed. This was so unusual as to be considered worthy of notice.The diameter of the tree was about three feet, and, judging by the number of annual rings, the age of the tree was in the region of one hundred and twenty years. At a point in the middle of the trunk and about four feet from the ground a distinct cavity was noticed. On careful examination it was found to be a definite air-space. On either side was protoxylem area what is technically called a crown. The accompanying photograph (Fig. 1) illustrates the appearance of the trunk, where there were two distinct protoxylem areas. Fin. 1. Two similar crowns and a bark-lined enclosed cavity within the trunk of an elm tree.The distance between the crowns was roughly inches, and the width of the slit was less than a quarter of an inch; its length at the longest portion ten inches, and it extended some two feet vertically in the trunk. There were fifteen annual rings between each of the crowns and the cavity. Above below that region the stem was quite normal. The cavity was lined with bark which had retained normal appearance.What appeared to have happened was that the while still young, had, for some reason, forked equally; perhaps the terminal bud had been injured the two forks had grown apart for some years each was fifteen years old. Previous to this something had caused the two forks to anastomose,the subsequent growth of the tree had enabled cambial activity to form a solid xylem cylinder round the portions of the two forks which had not fused together. So far as one could judge, great pressure had been brought to bear on the inner halves of the two forks, since the enclosed portions of the bark were, as can he seen in the illustration, quite straightened out. There remained only a thin lens-shaped cavity in the middle of the trunk. This cavity was lined, as has been noted, with bark, which had preserved its structure during the hundred odd years it had been enclosed. The sap-wood immediately below this bark had long since lost its function, and had assumed the appearance and, presumably, also the properties of the heart-wood. Nothing can be found regarding the history of the tree, and it would be interesting if any readers of TATURE could suggest how the rejoining of the forks came about, if that be what happened. There was nothing to suggest that it had been brought about artiflcially.

ISSN:0028-0836    

DOI:10.1038/120513a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THE experimental studies described in a previous note in NATURE (April 23, p. 601) have been continued by one of us (C. M. Sogani) and the structure of some thirty-five liquids has been studied by X-radiation. The present note indicates briefly some of the outstanding resultsof the investigation.The twenty aromatic liquids examined indicate a remarkable variation of the structure of the diffraction halo with the form, position, and mass of the substituent groups which replace the hydrogen atoms benzene. Ortho-, para- and meta-compounds are readily distinguished by their X-ray liquid haloes. When the benzene ring is loaded in an unsymmetrical manner, there is a broadening of the halo, which is the more striking the heavier the mass of the substituent group. The research furnishes numerous examples of this effect, a striking illustration being the difference in the haloes due to aniline and nitrobenzene respectively (Fig, 1 (a) and (5)). In several of the liquids, the halo becomes doubled, a good example being that of mesitylene, where the two rings are of nearly equal intensity. Fig. 1.?Diffraction babes, a, Aniline; b, Nitrobenzene.The aliphatic liquids examined include several of the paraffins, some alcohols, and an extended series of the fatty acids ranging from formic acid up to brassidic acid, which has a chain of 22 carbon atoms. The results confirm the prediction of Raman and Ramanathan (Proc. md.A8. Cult. Sc., vol. 8, p. 154; 1923) that with such asymmetrical molecules, we may have morethan one halo, the sizes of which correspond to different special configurations of neighbouring molecules relatively to each other in the liquids. The most striking illustrations of this are furnished by acetic acid and glycerine, each of which gives two haloes, corresponding respectively to the mean distance between neighbouring molecules which lie side by side and those which lie end to end. With very long molecules, however, only the former type of halo appears on the plates, and its size, as expected, is found to be independent of the lengthof the carbon chain. With the earlier members -of the aliphatic series, noticeable variations appear both in the size and the character of the halo with increasing length of the chain. The case of liquid mercury, which has also been examined, is of great interest in view of the monatomic character of its molecules, and also in view of the theoretical proof by Raman and Ramanathan (bc. cit.; 1923) that the X-ray scattering by liquids at small angles would be determined by the compressibility of the liquid. Mercury has the smallest compressibility of all known liquids (39 x 1012), and in agreement with the theory of Raman and Ramaathan, it is found to give a halo with a sharply defined inner margin and a very clear space within.Further details will be found in papers appearing in the Indian Journal of Physic.

ISSN:0028-0836    

DOI:10.1038/120514a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature