摘要:

THE growth of knowledge, and the necessary limitation arising from the age and duration of school life, create an ever-widening between the actualities and posslities of education. The boy or girl 1 s hool to enter some profession is able to secure suitabk fui:ther training in pait-time classes at a local technical school or college. But t er are many men and women who h9re..1/ special training, or have already lbtai ed w at they require, but have intellectual riecvhich call for satisfaction. They read newspapers and books; they are members of clubs or societies; they acquire an interest in social or political or economic problems, or in philosophy, or literature, or science; and they enter into eager controversy on the problems of the day. Those who possess depth of feeling or understanding, whose interests are not the languid ephemeral interests of the man in the street, realise the need for wider and deeper knowledge, for training in methods of study, for direction of reading, and for friendly guidance and criticism. Training of this kind has been provided for many years in University Extension Courses, in the last quarter of a century in classes under the Workers Educational Association, and more recently in the London Literary Institutes. The work has become an integral part of national education. It is aided by Local Education Authorities, and has acquired sufficient magnitude and importance for Treasury grants to be administered under a separate set of regulations the Adult Education Regulations of the Board of Education.The training in these classes exists in response to a distinct demand. This demand is usually for something which bears upon the wider aspects of intellectual life rather than upon the narrower requirements of an occupation. It represents a desire for knowledge for its own sake, a desire to share in the intellectual heritage and to understand some aspect of the material or intellectual progress of the generation in which they live. It arises at later age than that at which students pass into technical schools or universities for professional or occupational study; and however complete may be the facilities for the continuous full-time education of all who appear when young to be capable of profiting by it, the need for this kind of training will remain.From this point of view the field of adult education is not limited to economics, to history, or to literature, but extends over the whole field of human knowledge; and we welcome the interesting and instructive report 1 of the Adult Education Committee recently issued by the Board of Education. When the Committee commenced its labours in 1921, most of the classes were in economics and history. At the first meeting, Mr. Fisher, then president of the Board; expressed the hope that the Committee would investigate the possibility of extending the range of studies in the adult education movement. As a result of its observations the Committee is able to note in 1927 a distinct tendency in this direction. In particular, classes in English Literature have increased greatly both in numbers and in proportion to the whole, and the growth of interest in Music and the Drama has also been considerable. But the Committee deplores the fact that there has been no corresponding growth in the number of classes in Natural Science. After reviewing the value of natural science as a humane study, in everyday life, and in industry, the report discusses the evidence of an interest in the subjects which fall under the vague yet comprehensive title, There appears to be some doubt whether the interest is nQw so great as it was fifty years or more ago; but the conditions of life are so different that no comparison is of much value. A much greater proportion of young people obtain instruction in the elements of natural science at school; a greater number of students attend technical schools in which the instruction is far more specific and highly organised, far less academic or of general interest, than it was even twenty-five years ago; local travelling facilities have immensely improved, and the means of employing leisure are more varied than they used to be; Local Education Authorities are more independent of external aid, and inclined, on the ground of expense, to concentrate on what appears to be the primary function of the local technical school. The pioneer work of the famous men who upheld the banner of science in the last century can scarcely be compared with that expected in a tutorial class conducted by the Workers Educational Association to-day. The circumstances have altered and the aims are not the same.In regard to the existing provision, we note that in 1925 6 the number of courses in Natural Science recognised under the Adult Education Regulations was 47 out of a total of 1224; the number of students attending these courses was 935 out of a total of 26,806. These figures do not include non-vocational courses promoted by Local Education Authorities. From such statistics as the Committee has been able to obtain, it concludes that the study of Natural Science is being neglected in comparison with other studies. The courses described or commented upon cover a wide field, but are conveniently grouped under biology, geology and geography, and the physical sciences. By reason of their human interest, classes in biology have been especially successful, and in some cases have been continued for four years or more. Very little apparatus is required, and the classwork is supplemented by field excursions and visits to museums. Geology and geography also call for little special accommodation or equipment. The requirements for physical science vary, widely with the branch chosen, but even where laboratory work is not necessary there may be a need for a degree of mathematical knowledge not usually possessed by adult students.Apart from differences of method, advocated by different witnesses, there appears to be a greater similarity of content, and more uniformity of aim, in courses in bioogy and geography than in physical science. The former almost invariably suggest a wide view of the universe and of the evolution of living things; the latter vary from Chemistry of Everyday Life or Chemistry in the Home to Modern Views of Matter and similar subjects. There is an implication on page 20 of the report that biology is more widely studied in Tutorial Classes and the physical sciences in Extension Classes; and on page 52 the mathematical and experimental requirements are referred to in support of the view that physical science is less suited to the method of a Tutorial Class. But since the original condition of the Adult Education Regulations that the instruction must aim at reaching, within the limit of the subject covered, the standard of University work in Honours, now only applies if the subject is such as to make that a possible aim, the suitability of physical science for a Tutorial Class seems to depend mainly upon the syllabus and the teacher.The report recognises the need for competent teachers, and advocates the appointment by the universities of staff tutors for this work. It complains that the high degree of specialisation at the universities does not provide men with the requisite breadth of training. On this matter we are at one with the Committee. But something more than breadth of knowledge is required. The man who is to attract and retain adult students requires personality. He must have sympathy and understanding, and be able to realise the content and attitude of mind of those who come to him for instruction and inspiration. He must have such a grip of his subject that he can break down traditional and academic barriers between branches of knowledge barriers which, while not inappropriate in a full-time university course, are unnecessary and frequently out of place in a course which will rarely permit of more than 150 hoursinstruction; he must know not only how to learn himself, and how to present his subject attractively, but also how to train his student to learn for themselves. Also, if he wishes to enjoy, and help others to enjoy, the pleasure of learning, if he wants to feel, and make others feel with him, the exquisite thrills which accompany mental growth, he must have a command of language which will enable him to clothe the dry bones of fact and theory, and make them live. While we share the desire of the Committee to see an increasing number of classes devoted to the study of natural science, we do not desire a rate of increase greater than that of the supply of cornpetent teachers. For if the teaching is to be humane, if it is to reveal the patient and accurate observation involved in scientific investigation, if it is to train judgment, if it is to create awe and reverence for the wonders of the universe, it must be based upon qualities for which academic attainment is neither a measure nor a guarantee.1 Natural Science in Adult Education. Paper No. S of Adult Education Committee, (London: H.M. Stationery Office, 1927.) Sd net.

ISSN:0028-0836    

DOI:10.1038/120609a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

DESPITE the recent large output of books dealing with X-rays and their applications, this addition is a very welcome one, Himself a leader of the German school, Dr. Mark has brought to his task a quite exceptional knowledge of the theory and practice, and it would be difficult to find any one better fitted to produce a sound as well as a helpful text-book of this subject. Issued as a volume of a new handbook of applied physical chemistry, it is described by its author as a book intended for the guidance of chemists and engineers, It is more than this; it is a book to be possessed by all who have to deal with X-ray problems. The main object is to introduce the reader to, and train him in the methods of, X-ray crystal analysis, and for such an end to be successful it is necessary to discuss the nature and properties of X-rays, the theory of the older crystallography, and then .the applications of X-rays to the problem of the solid state. This is briefly the general scheme of the book. In the earlier chapters the methods of production of X-rays are described in a very practical way. Details and working instructions of the essential apparatus are given, details sufficient to enable even the inexperienced to select a suitable equipment and to know in advance the difficulties he is likely to meet and how they may best be overcome. There follows an account of X-ray spectrometers and spectroscopy, and of the most important properties of the rays themselves, with very complete tables of wave-lengths and other useful data.In the same masterly way, the subject of crystallography is introduced, and this section contains all the formula3 and information that are likely to be required. Before proceeding to discuss the actual procedure of X-ray analysis, Dr. Mark inserts a chapter on the essentials of the wave theory of diffraction, leading up to the crystal grating by a discussion of the simpler optical systems. He thus gives the necessary analysis to which he can refer when the question of intensity interpretation has to be discussed later. The author is now in a position to deal with his main problem, the application of X-ray to the structure of the solid, and he proceeds to do so in a very thorough and systematic manner. So far as it is possible to lay down definite rules of procedure, he does It and reproduces for this purpose, in convenient form, tables differentiating the various space groups. These- Stables, although not quite free from errors, should reduce the time and labour of obtaining the space group of a crystal to a minimum. This determination of space group, or classification of the crystal as belonging to one of the 230 possible configurations, is now a routine business and should always be possible if suitable material is available. But the details of atomic arrangement are not, as a rule, determined when the space group has been found. The complete solution of the structure involves also a discussion of the intensities of the X-ray reflections. This is a much more difficult proble ru, but in the section devoted to this question the reader will find an excellent survey of the position as it stands to-day.It is difficult to think of anything essential which has been omitted. Whether his material is in the form of a single crystal, a random collection of small crystals, or in that very interesting state in which the crystallites are not oriented at random but have some direction in common, the worker will find here the- necessary information to enable him to attack his problem. No attempt has been made to gloss over the difficulties, but, in spite of this, the hook is essentially a practical one. Some of those to whom it is especially addressed may find it difficult in places, but they can rest assured that they are not likely to find a simpler yet equally comprehensive account elsewhere. The occasional excursions into mathematics need not deter them unduly. They will find that the working rules are often independent of this analysis and quite intelligible even if all the steps leading to their deduction have not been followed in detail. Here, then, is a book especially for the practical worker, a book which he will keep on his desk and to which he will find himself continually referring Every one whose interest lies in this field owes Dr. Mark a debt of gratitude for his labours in writing such a sound and such an eminently useful work, and there will be many among them who would appreciate the appearance of an English translation in due course. We have but one quarrel with it, and that is its price. It is certainly a large volume, and the many excellent illustrations and tables must have increased the cost of production, but it seems a pity that a book which is invaluable to all con cerned should be issued at a price which puts it almost beyond the modest purses of many to whom it would be most helpful.

ISSN:0028-0836    

DOI:10.1038/120611a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THE Government of Assam is evidently not content with that superficial knowledge of the decaying culture of its subjects which is so frequent a failing of governments which have to deal with primitives; for the present volume, published under Government auspices, is an addition to an important series of monographs on the more primitive peoples of Assam and maintains the high standard of the earlier volumes. Mr. Mills gives us the results of an intensive study of one important group (comprising a population of some 30,000) of the peoples of the Naga Hills. Material culture, social organisation, and religion are exhaustively dealt with, and a short grammar of the language is given.It is interesting to find that the clans in most of the Ao territory are grouped into three exogamous phratrics, an unusual form of organisation, while in one part there is a dual organisation such as we find in parts of Melanesia, It has not escaped Mr. Millss notice that Melanesian affinities are very numerous, and his book affords further proof of the close cultural connexion between the two areas. A feature of the social organisation, worthy of special remark, is the grouping into three-year age- grades, a grouping not brought about by initiation but directly dependent on the year in which a person is born, Grades within the mens house result from this arrangement, and even the elected councillors of the village form a wider age-grade of a generation, the older generation of councillors being eventually replaced en bloc by the next generation below. The Ao believes that he has a number of souls, one of which is, perhaps, better regarded as soul- substance, though Mr. Mills does not use this term. Head-hunting, a most important institution of the Nagas, is closely connected with these beliefs, for the souls of dead men are wanted to fertilise all vegetable and animal life and to add to the general stock of vital essence in the village, and the soul is located in the head above all other parts. Sacrifices to stones and spirits are most important, and there is a complex series of feasts with sacrifices by means of which a man acquires merit, Some interesting notes on the effects of mission work are given in an appendix, and Mr. Mills reaches the conclusion, favoured by most anthropologists, that, although the mission may confer considerable good on the native, much harm is also done by the destruction of tribal life beyond the point of political necessity.The usefulness of the book is augmented by a chronological bibliography of the Naga Hills by Mr. Hutton, who has also added valuable notes to the text. The book is well illustrated and provided with a map. There is an excellent index, Mr. Mills is to be congratulated on his valuable contribution to ethnology, for, as Mr. Baif our remarks in the foreword to the work, detailed ethnographical monographs, such as the present work, compiled without the bias of any fixed and inelastic theory, afford to the comparative ethnologist reliable material upon which he can work, and, it may be added, such monographs are comparatively rare.

ISSN:0028-0836    

DOI:10.1038/120612a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

SERIOUS study of the phenomena of the mediumistic trance can be divided into two .main classes: the work hitherto done through mediums on supposed supernormal communications which are alleged to come from the dead; and the elucidation of those products of automatism usually styled the cross correspondences. Of these, the first class is of. some considerable scientific interest, and the present volume is a further contribution to the subject along those lines. A devoted married couple, Mr. and Mrs. White, were separated by the death of the former; and the latter, seeking consolation, applied to Sir Oliver Lodge for assistance. As is usual in such cases, the applicant was put in touch with Sir Olivers secretary, Miss Nea Walker, the compiler of the present volume. With her help Mrs. White visited certain mediums in Cardiff near her home, and with them she obtained information which, it is alleged, they could not have normally known. This beginning was supplemented by sittings on behalf of Mrs. White taken by Miss Walker with the medium Mrs. Leonard, and also by private sittings with Miss Walkers sister, Damaris, who is supposed also to possess psychic faculties. Later, Mrs. White herself had sittings with Mrs. Leonard, and finally dying she came through at sittings which Miss Nea Walker arranged with Mrs. Leonard. This is, in short, what is known as the White Case, and it is here presented as evidence for the survival of bodily death and the continued interest in, and knowledge of, earth conditions by those who have passed beyond the veil.The evidence consists in the main of a mass of intimate and trivial information recognised as appropriate by Mrs. White, and in many cases given through mediums and to sitters unknown to her or to her deceased husband. Such trivialities do not weaken the evidence. In certain cases they strengthen it, especially when the material is of such a nature as not to lend itself easily to coincidence. Thus, at one sitting when Miss Walker was acting as deputy for Mrs. White, the communicator, purporting to be Mr. White, remarks that he thinks that at the end of the previous week; about nine days ago, they were looking at a sunset together. As a matter of fact, exactly nine days previously, Mrs. White had noted down in her diary that she had been looking at a sunset and had been thinking of her life with her husband whilst doing so. There are a good many incidents of a similar character scattered Up and down the records of the sittings, and interspersed among them are names of persons connected with Mrs. White which would not have been easy to obtain through normal means. Now it would be hazardous to advance the supposition that all the information given through the various mediums and here described was derived from normal sources revealed fraudulently. Certainly it would seem that at least some of it was derived from some hitherto unrecognised source which is usually described as supernormal. However that may be, it is a pity that some competent psychologist, alive to possible sources of error, did not supervise and systematise the experiments from the start. Thus, we are told that Miss Walker originally sent Mrs. Whites letter asking for assistance to a man in Cardiff. Is it not legitimate to ask who this man was; whether he knew of the mediums to whom Mrs. White afterwards went; whether he showed the letter to any one, and if so, whether these persons knew the mediums concerned? These and many more similar questions immediately arise, but no answer to them will be found in thefl pages of this book. Again, how unsatisfactory it is to have one of the principal mediums, Damaris Walker, living in the same house with the principal investigator. Moreover, what an opportunity was missed when Mrs. White herself died. Instead of sending someone who was not aware of Mrs. Whites death to take a sitting for Mr. White to communicate, Miss Nea Walker herself goes, and, presupposing some telepathic rapport between herself and the medium, it is not surprising that Mr. White affirms . the presence of his wife, although strangely enough the control, Feda, does not seem aware of it.To any one acquainted with the history of the evolution of the human mind and not already persuaded, The Bridge will scarcely carry conviction. It may stimulate independent investigation of the problems underlying the real meaning of the odd phenomena associated with the mediumistic trance. Systematic experiments, independently checked and verified at every stage are, it is admitted, very difficult of execution, but certainly ought to be attempted. Thus, it ought not to be permitted, as . was, done in the present case, for the sitter to be present alone with the medium and take personal notes in long-hand. It is admitted in the White Case that a selection has been made, and it is obvious in what directioii it operated. If telepathy occur at all, then the laws underlying it will only be discovered through the most rigid control conditions being applied. At present we see little appreciation of this fact in the writings of psychical researchers. It remains to be seen whether, when sufficiently strict control conditions are applied, the . phenomena tend to disappear as seems to be the case with the so-called physical phenomena of spiritualism. When normal knowledge, chance coincidence, common associations, deliberate fraud, and hyperasthesia are eliminated, what remains? Is there, in fact, any residue left for examination ? Certainly in such phenomena as are exhibited in the published cross correspondences there would appear to be little, if any. In the communications given through mediums there would seem to be something for which no normal explanation is readily available, and this volume provides a good example of the latter category.

ISSN:0028-0836    

DOI:10.1038/120613a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

WHEN the professor of zoology in the Calcutta V V School of Tropical Medicine, and a worker in the Central Malaria Bureau of the Government of India with previous wide field experience in Ceylon and India, collaborate in a monograph on the investigation and control of malaria intended for men of the Indian assistant-surgeon class, its scientific and practical hygienic value are assured; when they dedicate it with respectful homage to the wives of research workers, in recognition of their sufferings in the cause of science, the illumination of humour helps perspective; and when they permit in the book the issue of advertisements of material pertinent to the subject, they perhaps but follow closely in the footsteps of the Schools distinguished founder, for it was he who persuaded the merchants of Calcutta to contribute so liberally, and, so far as they were concerned, so unexpectedly, to its finances that they assured him that his missed vocation was that of company promoter. The first two chapters of the book deal with the malaria parasites in man and anopheles andacknowledge fully the writers indebtedness to Wenyons Protozoology, although Knowles is in error in attributing to that book and author the original intimation that if Plasmodium ovate Stephens be valid species its valid name is P. minutum Emin, 1914. That effect of the working of the Code of Zoological Nomenclature was indeed pointed out in the Tropical Diseases Bulletin three years earlier. While on this subject, it may be noted that the specific names of the anopheles cited do not all appear to comply with the law of priority. These chapters contain three valuable coloured plates of the various stages of develop- ment of the three species of Plasmodium parasiting the blood of man, and a fourth, particularly striking in its simplicity and clearness, of the relations of the human and anopheline cycles of the plasmodial life-history. There is one point on which Knowles lays some stress, the statement that gametocytes do not appear early in an infection, not perhaps for ten days or more, their appearance being due, it is suggested, to conditions becoming unsatisfactory for schizogonic multiplication. Warrington Yorke and Macfie, in their transmissions of P. vivax by mosquitoes in the treatment of general paralysis, have, though rarely, found gametocytes in the circulating blood as soon as any forms have been discovered there, and, in all instances, two or three days later. It is reasonable to conclude that gametocytes come into existence as soon as do schizogonic forms, but in numbers too sparse to be detected in the circulating blood by our present diagnostic means.The reasonableness of this explanation is strikingly illustrated by an incident cited in the book where some fifty thin smears from one man were distributed among the School class with the view of eliminating P. falciparum infection, for it was intended to use this blood, which was infected with P. vivax, in the treatment of general paralysis. Rings suspicious of subtertian malaria were found in three smears, and a crescent in a fourth. Should the sexual forms, essential for the survival of the species, appear only when conditions are unfavourable for schizogonic multiplication, the observation would have wide zoological implications, so that hesitation in accepting this position is justified. With experience of the diagnostic uncertainty of thin films, such as has just been indicated, there is little wonder that Knowles is a convinced advocate of the thick film for the diagnosis of malaria, and full and careful directions are given for its preparation with a view of ensuring that plasmodia shall always be detected therein if they are present. Culture is advocated for diagnosis if the thick film prove negative and doubt still remains, thus follow-ing Sinton, in whose hands it has in these conditions been successful, the amount of blood usable amount-to 1 e.cm. A fifth coloured plate illustrates the normal and abnormal cells which may be found in a stained blood film.Very convincingly, Knowles uniolds the argument against parthenogenesis in Plasmodium, but, unfortunately, it is not, as he writes, now as dead as mutton; it has recently been sponsored by a great French scientific society in considered advice to the French Government. The line of treatment inclined to is Sintons alkaline quinine mixture, but as regards total dosage sufficient stress seems scarcely to be laid on the difference in reaction to the cinchona alkaloids which is shown by a recent and by an established infection, both conveyed by the mosquito. Perhaps for the books purpose such stress is useless, in view of the unlikelihood of detecting a new early infection in those who have been infected in, and have relapsed or been reinfected since, childhood. The cinchona alkaloids other than quinine, and the mixture known as cinchona febrifuge, are considered. The very strong reasons against giving quinine by the intra-muscular route are fairly marshalled, the invariably resulting necrosis is stressed, and some of the appalling consequences illustrated. After all, seeing that the Indian sub-assistant surgeon does give intravenous injections of tartar emetic for kala-azar at the rate of about two a minute in Assam, there is little excuse by any one to avoid the sure and rapid intravenous route for quinine, where the oral route is contraindicated.Senior-White describes the making of a malarial survey, and the design, construction, and maintenance of anti-malarial measures, and furnishes appendices. These comprise the breeding places and distribution of Indian anopheles, and a key for the identification of the imagines. A corresponding key for the mature larve is accompanied by a sketch of the entire larva with its anatomical parts named; an idea which will, no doubt, be extended to the imago in another edition. Both keys are usefully illustrated throughout. The last appendix consists of a copy of the specification which has been found so valuable for the construction of subsoil underdrains in the Federated Malay States, A considerable bibliography follows. The book fills well the limited function for which it is intended.

ISSN:0028-0836    

DOI:10.1038/120614a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THIS book is very well illustrated; it contains reproductions of photographs and drawings of Halleys and other comets, made at the principal observatories, also photographs of sunspots arid the corona, and a large coloured drawing of a solar prominence. A considerable part of the text is taken up with quotations from the writings of well-known astronomers; some of the passages quoted were, however, written before the recent advances in atomic physics, and are now somewhat out-of-date. Cometary physics are very difficult to explain in a perfectly satisfactory manner, and it is unwise to be too dogmatic in condemning any suggestion as being certainly unsound; some of the authors suggestions are, however, rather difficult to accept. Thus he suggests that the tails of comets are bounded by an envelope, which he 4appears to picture as a sort of membrane. It must be ad- mitted that the well-known drawing by Gen. G. H. Willis of the great comet of 1882 lends some support to the suggestion; yet it is difficult to reconcile it with our knowledge that the tail is not at rest with respect to the head, but is continually being driven outward by powerful forces. Again, the author invokes currents in the interplanetary medium to explain some features of the tail. The study of cometary movements clearly shows that the medium offers no sensible retardation to the motion of the comet as a whole; still less could its differential action between different parts of the comet be sensible. There are similar difficulties in some other suggestions; still we may admire the authors enthusiasm for his subject, and his desire to throw new light upon it, even if we are unable to accept all his ideas.

ISSN:0028-0836    

DOI:10.1038/120615a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

IN this admirable volume, Prof. Clark gives what is probably the first extensive and scientific account of the progress made in the application of X-rays to the solution of the special problems of industry, Even to readers more or less in touch with X-ray work in general, the extent and variety of the subjects dealt with in the book will come as a surprise. The application of X-rays to the solution of problems connected with the behaviour of metals and alloys under strains, with the composition of chemical compounds, with catalysts, colloids, textile fibres, varnishes, dyes, soaps, dielectrics, adhesives, abrasives, cements, coal, and gems, are some of the many subjects with which the author deals. It is not surprising that he foresees a great future for this new and rapidly growing branch of applied science. Prof. Clark writes not only with enthusiasm but also with knowledge and judgment, and has succeeded in condensing into small compass a considerable amount of information, much of which is drawn from sources not too easily available in Great Britain. The book is excellently written, well illustrated, and charmingly produced. We congratulate the author on having so admirably filled a real gap in our current scientific literature.

ISSN:0028-0836    

DOI:10.1038/120616c0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THE identification by MM. F. Croze and C. Mihul of a number of intercombinations between quartet and doublet terms of O II (C. R., vol. 185, p. 702), which has been announced since my letter of last week was written, provides important data for the further consideration of Mr. Bowen's suggestion as to the origins of certain lines in the spectra of gaseous nebulæ.Bowens values for the quartet terms of 0 II were based upon a sequence of three P terms, and it was understood that while these were relatively correct among themselves, they were not necessarily quite correct with respect to the previously determined doublet terms. The discovery of intercombinations, however, leads to a correct relation between the two sets of terms. Without going into details, it may be stated that while Bowens estimate for the S2 term was 283366 (Phys. Rev., vol. 29, p. 243), the new data indicate a value of 283028, within limits of error depending upon the measurement of lines in the extreme ultra-violet. Thus, adopting Bowens interpretation of the nebular lines X3728, X3726, we have A air. v (vac.). Combn. Bowen.372891 268099 482 2D3 2D3=256208; 82=283018 372616 268297 4S22132; 2D2=256192; 82=283022The mean value of S2 = 283020, is in remarkable agreement with 82 = 283028, as determined entirely from laboratory spectra, involving lines in the extreme ultra-violet. Taken in conjunction with the evidence in favour of similar irregular combinations of terms of N II and 0 III, this result leaves little doubt that Bowens interpretation of some of the chief nebular lines is correct. Since the ordinary combinations which build up the laboratory spectra of 0 II, 0 III, and N II do not occur in nebuhe, it would appear that the conditions in nebula which facilitate the occurrence of irregular combinations of deep spectroscopic terms are such as to prohibit the regular combinations which produce the familiar laboratory spectra of the same elements.I should like to take the opportunity of making a small correction to my letter. In the paragraph on p. 582 in NATURE of Oct. 22, beginning with Bowens assignment of the strong nebular lines X372891 and X372616 to 0 II leads to term values for 2D32 of the expected order of magnitude, and the consequent calculation of the red line X7325 . . ., S should have been substituted for 2D32, and the word consequent should have been omitted

ISSN:0028-0836    

DOI:10.1038/120617a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

To answer completely the letter from Prof. Davis, published in NATURE of Sept. 3, would take too much space, so, as he suggests, I leave my papers to speak for themselves when they appear. To explain the presence of basaltic stones on the ‘barrier’ reef by a filling in of the lagoon, and its re-excavation, is really a special pleading against the simpler hypothesis of a once continuous reef; I can myself suggest a much simpler alternative, namely, by their being floated across entangled in the roots of trees, floated out to sea by floods. I reject this means of transport, however, because the stones areinvariablyrounded, which could only be the ease when the tree has been uprooted from an alluvial flat. The reefs and their embedded stones are certainly pre-glacial, when such flats were of small extent, especially if, as Prof. Davis holds, the valley mouths were drowned, and the stones, in the great majority of cases, could have been only angular fragments of the rocky sides of torrents.I can assure Prof. Davis that the geological aspect in general, and his own work in particular, are fully recognised by all workers who, like myself, have been so greatly influenced by Prof. J. Stanley Gardiner, and his forthcoming book will be read with the greatest. interest. At the same time biologists cannot agree that their contribution has been, or will ever be, the less significant side of the problem, and I suspect that Prof. Davis did not quite intend this meaning; the geological aspect is fundamental, but alone it is as dead as faith without works. The mention of such names as Gardiner and Mayor is sufficient to prove the value of biology, but, as the present discussion is on the reefs of the eastern Pacific, it may be more interesting to take new, and as yet unpublished, examples from that region. The Marquesas have been the subject of much geological theory, but it was reserved for a biologist to find that the absence of reefs from that group is a matter of coral ecology after all. The foundation, growth, and recession of reefs cannot be completely understood without even more knowledge of the life of corals than we have at present.. This subject is only at its beginning. These basaltic stones scattered upon, and bedded into, the Tahitian barrier could never have been seen by a geologist, and I think their discovery may be a by-product of the long hours I spent during seventeen years inspecting pearl beds in the Red Sea. Also the fact of the recession of these reefs is as interesting to the geologist as to the biologist, but it can safely be said that it would never have been discovered by the former. The importance of the origin of arf-resisting reefs, as distinguished from mere loose heaps of coral, has been insisted upon by Prof. Davis himself. This is decidedly a biological problem, depending upon the interaction of the stony seaweeds and other organisms with coral, as described by Gardiner, and it is also illustrated by the rejuvenated portions of the Tahitian reef edge.Prof. Davis explains the occurrence of high cliffs on the north side of Moorea Island by a local delay in reef building through the outwash of alluvium from the two fjords of this coast, As he states, this alluvium would be carried westwards, and it would therefore affect only the western two-thirds of the coast, and the reefs would be markedly narrower westwards than they are to the east, which is not the case. The uniformity of the width of the reefs is one of the curious features of the whole group, and those of Moorea well exemplify this. In my account of the Island I have taken the view that the straight north coast is faulted, the two fjord-like bays are due to explosions, while the south coast has tilted downwards and drowned its valleys. All this occurred early in the islands history and has had no effect upon the form of itt? reefs. I have no wish . to make this a general statement, applicable to any other island. Agassiz gives no detail of his dredging in the Tahitian lagoons, and I have good reason for distrusting his general statements. My own dredgings have been far too few, but the most enclosed of all the lagoons, from Papeete round the north-west quad- rant of the island to Taapuna Pass, was thoroughly explored by dredge. Its sand is surprisingly uniform in character, angular and fairly coarse, and contains only 15 per cent. of non-calcareous matter. The absence of the red mud, which is poured in at every heavy rain, is remarkable. I conclude that thii lagoon is filling in, but much more slowly than I, for one, expected. Proof is wanting of what is happening at the bottoms of those lagoons of Tahiti which are certainly being excavated for the first few fathoms of their sides, and I hope to obtain it by a series of dredgings on my next visit. If at the same time some inexpensive borings could be taken (1) in the valley flats, (2) at the bases of the marine cliffs, (3) in the reefs, we should not be dependent upon inference for the discussion of the points raised by Prof. Davis, and by my own work. I do not reject the evidence for subsidence given by the valley flats, but pending positive information, they are as well accounted for by lateral cutting of their streams as by the infihling of bays. Flat-bottomed valleys abound wherever a streams load of alluvium is excessive, conspicuously, e.g., among the mountains of the Red Sea. Finally, I see no reason why subsidence should convert a fringing into a barrier reef, but, in Tahiti, see evidence that drowning would tend the other way, to the production of a wide f

ISSN:0028-0836    

DOI:10.1038/120618a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

WHEN two fluids which have no chemical action on one another and are mutually insoluble, are well shaken together, the mixture consists of small globules of one fluid embedded in a matrix of the other, and is in general less fluid than either of the constituents taken separately. Common examples of this sort of stiffening are to be found in cream, mayonnaise sauce, and butter (mixtures of oil and watery fluid), but the most striking case is that of oil and mercury, which forms a stiff black mud. In the first three examples it is the oil which takes the globular form, and in the last the mercury.Since the surface tension of oil-water is much less than that of mercury-oil, it would seem that the surface tension difference is not the factor determining which of the two fluids shall persist as globules. This probably depends on the qualities which tend to make fluid films stable. The stiffening of these mixtures may be explained by the fact that when they are stirred or distorted, a flow has to take place in the narrow channel separating the globules and that this is resisted by viscosity. Suppose that a large number of small solid spheres are placed in a vessel, and are so disposed as to occupy the minimum space (i.e. that each is touched by its neighbours at twelve equidistant points), and that then fluid is added until the spheres are just covered. Tf now the arrangement of the spheres is disturbed in any way, the level of the fluid will fall in consequence of the increase of the volume of the interstical cavities, and the viscous resistance to be overcome is pro- portional (among other things) to the aggregate surface of spheres or, in other words, inversely as their diameter.When the spheres are globules of liquid, distortion of the mass will also cause a deformation of the individual globules, and this will be resisted by an elastic reaction due to the internal pressure, which exists in them by virtue of surface tension. The internal pressure in a globule of diameter D where the surface tension constant is T is equal to T/D, and this becomes considerable when D is small. In a mercury-in-oil globule, for example, if D is 1/2000 in. the pressure will exceed 40 lb. per square inch about as much as the pressure in an ordinary bicycle tyre, but in a collection of such globules, if deformed, the internal pressure may be much greater, for the deformation tends to make the globules into dodecagons, and the pressure is inversely proportional to the least radius of curvature of the deformed sphere. (In such fats as butter, in which the oil solidifies at low temperature, additional viscous resistance is offered to deformation.) It would be a waste of space to go fully into the quantitative (and fairly simple) relations between volume of the interstices as the arrangement of the globules departs from the minimum volume pattern, but the results may be shortly stated thus(1) In a collection of fluid globules closely embedded in a second fluid, resistance is offered to deformation by a force which is partly elastic and partly viscous, the viscous force being much the more important. (2) The resistance increases as the diameter of the globules diminishes.(3) When the globules are closely packed any deformation of the mixture involves an increase of volume, not, of course, of the globules, but of the spaces between them. The expansion of mixtures from this cause is well shown in such material as glaziers putty (oil and chalk). Putty when well kneaded is soft, and if rolled into a cylinder can be easily lengthened or shortened for a certain distance by applying force to the ends. If, however, the alteration of length exceeds a definite limit, the resistance increases very rapidly, as if the motion were opposed by a mechanical stop. At the same time, the appearance of the surface suddenly changes, losing its shiny gloss and becoming dull and matt. This happens when the particles of chalk, which at first were separated by oil, have been brought into contact, and further distortion withdraws the oil from the surface to fill the enlarged internal cavities. The same explanation applies to the dry patches which (as most people must have observed) appear for a short time round footsteps on wet sand recently left by the tide. Most people also must have noticed that by tapping on the sand with the foot, the surrounding area becomes wet and soft a quicksand in fact thus showing that the sand particles are separated by fluid, but the wet area quickly resumes the dry appearance when a steady pressure is applied.Many superstitions have collected about the character of real quicksands, and it would be a matter of interest to examine the conditions under which they are formed.

ISSN:0028-0836    

DOI:10.1038/120619b0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature