摘要:

IN every government department, much of the work dealt with to-day involves the consideration of problems which ar*' nical character, and presents, in co ,eqiince, the need for close collaboraff,oWpatt of officers bei4gin to the adminis±Live financial, aIdAh2i1Iba/iches of c7 . .IAZ. IJ the department. In viev or-ne importance and, in many instances, the coplexity of the technical aspects of these problems, not only is it essential that the careers offered in the technical branches of the Civil Service shall be such as to attract men of the highest standard of qualification:s, but it is also necessary that the status accorded to the technical officers shall in every way be equivalent to that of the administrative officers with whom they are required to co-operate, in order that their position in the official hierarchy may correspond with the magnitude of their responsibilities, and thus effectively ensure that due weight may be given to their proposals. When the system of recruitment by competitive examinations was extended, now nearly sixty years ago, to the superior grades of the Civil Service, the work of government departments was almost entirely administrative in character, and the State had then only very recently entered upon its responsibility as the undertaker of an important technical enterprise, the telegraphs. The number, therefore, of men with a scientific training and technical experience required in superior positions in the Civil Service was strictly limited, and, in consequence, the competitive examination system did not apply to the technical staffs. But even then it was recognised that men of a superior standard of qualifications were, required for the more important positions on the non-technical side of the Civil Service, and steps were accordingly taken to provide a career in the higher division (now the administrative class) which should prove attractive to graduates of British universities; and at one time a career on the administrative side was practically the exclusive privilege of those who had entered the Civil Service by the higher division competitive examinations.Since the termination of the War, the administrative and clerical branches of the Civil Service have been completely reorganised on the lines of the Report of the Joint Committee of the Civil Service National Whitley Council issued in February 1920, and in connexion with this reorganisation an assimilation of the various grades of the administrative and clerical classes of the Civil Service has been effected; an improvement in the salary scales has, in some cases, taken place; and provision has been made for recruiting the administrative class partly by selection from inside the service. However, a proportion of the vacancies in the administrative class will, in the future, still be filled by men selected for appointment to the public service by means of an open competitive examination in the subjects embraced by the various honours courses of university institutions. Again, on the recommendation of the Asquith Committee, the salaries of the permanent heads of the principal departments of the State were, in 1920, raised to £3000 per annum, being in the majority of cases an increase of 50 per cent. On the pre-War scales. The deekpments which have been taking place in the activities of government departments during the past fifty years having had the effect of making administration dependent to an increasing extent on factors of a technical nature, their problems must, in many cases, be subjected even at the initiation stage to investigation at the hands of €˜experts.€™ Fuither, where specialised knowledge is rbquired, it is these experts€™ who have to work out the details; and, in the subsequent stages, the duty nocssarily falls upon them to supervise the execution of schemes, and they then become responsible for much of the administrative work involved.The altered conditions affecting the work of government departments have naturally resulted, in recent years, in a considerable increase in the numbers of the established officers of the €˜expert€™ class. The increase between the years 1914 and 1923 Was approximately 36 per cent. At the same time, a higher standard of professional knowledge has been called for and obtained, In spite of this transformation, no attempt has, however, so far been made to bring about a classification of the professional group, nor has any general scheme been introduced to provide a career on the €˜expert€™ side equivalent to that offered to the non-technical civil servant. Certain improvements in the salary scales of the various.grades of the professional group have,. it is true, taken place; the salaries of the heads of tIm professional and techilcal departments have been raised, but the increases fall far short of the. proportionate improvements in the salaries of the permanent heads of the principal departments of the State mentioned earlier, and the salaries of the professional and technical chiefs are to-day approximately two-thirds and one-half only of those of the administrative chiefs. This disparity between the salary scales of the teehnical and non-technical staffs is carried down into the lower grades; it is not confined to the officers employed at the head- quarters of government departments, but exists, although to a less marked degree, also in the cases of officers employed in the provinces. It has further to be borne in mind that the differ- ences in the salary scales are accentuated by the fact that promotion is normally quicker on the non- technical than on the technical side, and, therefore, the superior positions on the former side are, as a rule, reached at an earlier age, on an average, than positions on the latter side carrying equivalent responsibilities. The methods of entry into the various groups of the Civil Service differ so widely that a general comparison of the periods of time taken to reach the several salary scales of the administrative, clerical, and professional groups in the ordinary course of departmental promotion. would be misleading. However, in order to provide a concrete illustration, the careers have been traced of six university graduates who entered the administrative class (old higher division) during the period 1905 1908, and an equal number of university graduates who entered the technical side of the same department, during the same period, under an open competition scheme, the average ages of the entrants into the two elasses being about the same.On the administrative side, the average time taken by these six officers to attain the salary scale £700900 (the maximum of which is reached after eight years in the grade) was 12 years; one of these officers was promoted to an appointment on a salary scale £10001200 (the maximum of which is reached after four years in the grade) 18 years from the date of entry into the service. On the other hand, on the technical side the average time taken by the six officers to obtain their first step of promotion to the grade carrying (in London) a salary scale £450550 (the maximum of which is reached after four years in the grade) was 15 years; two of these officers were promoted to the next higher grade carrying (in London) the salary scale £600 £700 (the maximum of which is reached after four years in the grade) after serving, on an average, 18% years. It is perhaps not surprising, then, that of twenty-six university graduates recruited during the period 190710 on the technical side of the department in question, 68 per cent. should have resigned their appointments; the high percentage of these resignations seems to indicate that, in this instance, the career provide4 on the technical side of the Civil Service is not sufficiently attractive to university graduates.Further, the foregoing analysis shows clearly that to undertake specialist duties of a technical char-aeter in the Civil Service results financially in the penalising of the €˜ expert €˜ officers. An attempt is sometimes made to justify the inequality of the salary scales of the technical and non-technical groups in the Civil Service on the supposition thf the officers in these two groups are in no way comparable, the implication being that the duties of the technical group are of an order inferior to those of the non-technical group, but no reasoned or satisfactory arguments have been advanced to support such a contention. The more favourable treatment of the administrative group as compared with that of the professional group has occasionally been defended on the assumption that as it is the former group that sanctions the expenditure voted by the legislature, a wrong decision on its part would involve waste and a loss of public money. This argument, however, assumes that the decisions of the administrative group are always sound and correct, and it entirely overlooks the fact that when decisions affect the sanctioning of expenditure on technical projects, the question as to whether such expenditure will be prudent and profitable, or extravagant and wasteful, will depend wholly on the skill with which the technical details have been worked out; the ability of the technical officers who supervise its execution; and on the care in relation to administrative details exercised by them. Therefore, even in the event of a consistent absence of mistakes on the part of the administrative group, the actual avoidance of wasteful expenditure and of the unprofitable use of public money must, in the very nature of things, rest, so far as the preparation and execution of technical projects are concerned, directly on the skill, scientific knowledge, and technical experience of the professional group, that is to say, on factors which lie wholly and exclusively in the sphere of responsibility of this group.The contention has also been advanced in the past that owing to the great diversity of the duties which fall on the professional group of the Civil Service, and the fact that it is made up of not less than a hundred grades, it is not possible to devise a suitable classification scheme for this group. This plea has, however, lost much of its force now that an Act has been passed in the United States providing for the classification of civilian positions within the district of Colombia and in the field services (American Classification Act of 1923PublicNo. 516-67th Congress: H.R. 8928). Under this statute the €˜compensation schedules,€™ that is, salary scales, are grouped under five €˜services,€™ namely, (1) the professional and scientific service; (2) the sub-professional service; (3) the clerical, administrative, and fiscal service; (4) the custodial service; and (5) the clerical-mechanical service. The numbers of grades in the several €˜ services €˜ naturally vary, but a distinctive feature of the Act is that in the case of the two most important groups, namely, the professional and scientific service and the clerical, administrative, and fiscal service, the salaries of the topmost grades in each of them are identical, and in each of these €˜services €˜ certain grades, it is recog nised, represent positions of equivalent responsibility, which is in each case clearly set out, and they accordingly carry salary scales with identical minima and maxima. It should further be noted that in this Act the professional and scientific service occupies the position of paramount importance. The present-day methods of conducting the work in government departments are also, in some cases, open to grave criticism; they are productive of unnecessary duplication of effort, and consequently uneconomical. In practice, the reports of the heads of the professional and technical groups are addressed to the permanent head of the department, who, however, has frequently so heavy a burden to carry that he cannot personally deal with them, and the reports therefore pass into the hands of officers of various grades in his branch. The result is, as often as not, that attempts are made by clerical and administrative officers to criticise technical details, and a lengthy and wholly unnecessary correspondence, in consequence, ensues. In those departments in which the technical work is highly complex, and the magnitude of the operations carried on in relation thereto considerable, the whole of the duplication of effort referred to would be obviated if the burden of responsibility for the details of the technical work were definitely and unequivocally placed on the shoulders of the department€™s chief technical adviser. In certain cases the situation could, with advantage to the public service, be met by giving the administrative chief and the chief technical adviser a co-equal status, so that, whilst carrying out their respective duties in the closest collaboration, they should at the same time be held directly responsible to the Minister each for the work within his own sphere, instead of the latter being called upon, as is at present the somewhat illogical practice, to tenler his advice to the Minister through the former.If the unequal treatment of the administrative and professional groups in the Civil Service were merely a question of a certain class of officers being dissatisfied with its status, prospects, and remuneration, the subject could be dismissed without further comment. However, the matter is one which is far more serious. Under the present organisation in the Civil Service, and the system of conducting business in government departments, it is at times impossible, much to the detriment of the public service, for the professional men to exercise effective ontro1 over professional work, no matter how expert they may be in the technique of their profession; further, a considerable waste of energy on their part is also often involved: hence the urgent need for a thorough reform in matters affecting the status of the technical expert in

ISSN:0028-0836    

DOI:10.1038/120829a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

WHEN Hotspur quarrelled with Henry IV. he excused himself on the ground that the King€™s Messenger €œwas perfumed like a milliner, and €˜twixt his finger and his thumb he held a pouncet box, which ever and anon he gave his nose and took€™t away again.€ On the other hand, readers of €œRomola€ will remember that whenever Tito Melema did an unusually scurvy trick, his inventor left him in the hands of his learned friend Nello the barber, to be shaved, bathed, and perfumed, presumably in the hope that these processes might do something towards his moral regeneration. It would be unreasonable to suggest that Hotspur and George Eliot respectively represent the attitude of men and women towards the use of cosmetics and perfumes, but it is a curious fact that while men have been known to carry their antipathy to odoriferous fluids so far as to postpone a necessary visit to the barber merely to avoid them, the majority of women like these things, buy them, and sometimes use them so lavishly as to be a source of discomfort to their neighbours.The present - day demand for these glittering €˜wares is enormous; their illustrated slogans occupy but do not always decorate, or should we say in the modern art slang add ddcor to, the hoardings everywhere, the flapper and her too evident toilet accessories are the unfailing standby of the journalist hard up for €˜copy,€™ and the advent of a new artist in perfumery secures much free publicity in the press, especially in those quaint corners which editors still dedicate to €˜ ladies,€™ but which few intelligent women will admit reading. All this gives the trade in cosmetics and perfumes what Sir Lawrence Weaver might call a €œ smell of Babbitt,€ but it should be remembered that such modern necessities as soap, dentifrice, and medicinal preparations are none the worse, when their natural odour or flavour is covered, and that in this and other equally unobjectionable but less easily defined directions there is a large legitimate field for the exercise of the perfumer€™s art. It is primarily with such ends in view that Dr. Winter has ap proached his subject and compiled this book. Nearly 300 pages are devoted to discussion of the great variety of raw materials used in the industry, and thanks mainly to copious use of constitutional formuke for the components of essential oils, an enormous amount of information has been compressed into this space. Perusal of this section. leaves the reader with the kind of feeling, which must be experienced by an intelligent artisan who has just completed a conducted tour of a continental picture gallerya little bewildered, but satisfied that he has had all the starred pieces pointed out to him. So breathless is the pace that towards the end the guide has only time to ejaculate such things asbenzyl propionate, smells of jasmin with a suggestion of fruitand to sketch the formula, It would be remarkable if the guide did not stumble occasionally, and on p. 63 he appears to confuse myristic with myristicinic acid, though it is clear elsewhere that he knows the difference between the two. Scattered through this section are practical hints, which have an academic interest for the chemist, such as the statement that mixtures of vanillin and anthranilic esters are liable to stain the skin yellow, an involuntary testimonial to the reactivity of aldehydes, and the note on p. 212 that alloxan when applied to the skin produces a pink tint, due to the traces of ammonia present in perspiration, whence it appears that the blush of the modern maiden may originate in at least two ways, physiological or chemical, the latter being due to this ingenious application of the murexide reaction, A short summary of the fermentation theory occupies less than a page, and is an excellent sample of Dr. Winter€™s skill in compression and his conscientious desire to leave no part ofhis subject untouched.In the next section the author €˜gets down€™ to practical perfumery and discourses on the form of cosmetic materialsdistillates, creams, balsams, jellies, pastes, powders, emulsions, etc. with abundant descriptions and illustrations of machinery for producing these things and pages of formuhe for the delectation of the practitioner. Nor is the theoretical side neglected, for there are chapters on such fascinating subjects as the harmony of per- fumes, the reaction mechanism of vapour waves, the mechanism of the mutual transformatory reactions of perfume materials, and the influence of the method of mixing on the tonality of the mixture. Writers on this subject have a habit of diverging into musical terms such as notes, tones, and harmony when mere science fails them in terminology. These chapters are quite interesting, as samples of that subtle differentiation which we all find useful from time to time, though some of us are inclined to scoff at the Teutonic temperament which alone seems capable of producing it. Dr. Winter also provides a full description of modern toilet soap manufacture, written on the lines just described and including quite useful chapters on the cleansing and lathering properties of different kinds of soap, which may be commended to those who desire to find a reason for the faith that is in them regarding some particular brand of shaving soap. The last section deals with practical cosmetics, a subject about the present position of whidh Dr. Winter is not altogether happy, judging from his introductory remarks on quacks and their frequent occupation of a field which belongs to the physician. His discussion of the pharmacological action of some of the ingredients of cosmetics lends point to that suggestion, and, as he remarks, there is considerable danger in the indiscriminate use of such things as €œeau myst©rieuse,€ a perfumed solution of antipyrine, which on application to the skin deposits after a time a coherent coat of white powder; to theatrical artistes who .must produce such effects he recommends instead a solution of phosphotungstic or phosphomolybdic acid. The section is full of curious information of this kind, and is at least a remarkable tribute to the assiduity with which specialists in the art of cosmetics have ran sacked scientific knowledge, and the ingenuity with which they have applied, or perhaps misapplied, it.A question asked iii the House of Commons recently as to the possible dangers of the indis criminate use of cosmetics seems to indicate that there are people who take a hygienic interest in these things. To them, as well as to those professionally interested, Dr. Winter€™s book may be cordially recommended as a source of accurate and recondite information, and beauty parlour specialists who can read German wi

ISSN:0028-0836    

DOI:10.1038/120832a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

A RECENT visitor to America whose object was to see something of the teaching of the social sciences in that country was advised on landing not to omit the University of .North Carolina. How long, his informant added, the not conspicuously enlightened citizens of that State will tolerate the vigour and freedom of thought, especially in the dangerous region of social problems, now being displayed in their University, may be doubted. In any event, the study of the social sciences flourishes there at present. Sociologists are learning to regard The Journal of $ocial Forces as one of the best periodicals of its kind in any language, and to welcome additions to the series of studies to which the volume here reviewed belongs. Prof. North has made a sane and careful examination of a problem of the first importance. His treatment is scientific. Unlike nine-tenths of those who deal with this subject he is not the victim of any theory. The book cannot be called exciting; we have had, however, our full measure of exciting but superficial theories in sociology, especially from Europe. On the other hand, it is not ponderous, nor does it remind the reader of wading through wool, as do some of the contributions of his compatriots. What, he asks, are social differences ? Why do they arise? And what is their relation to social welfare ?To the first question Prof. North replies that social differences may be divided into those of function, rank, culture, and interest. Of these, those due to differences in rank arc the most important. They include differences in respect to rights, privileges, or esteem, which may be personal, political, economic, religious, or honorific. These differences are the foundation of €˜classes€™ in the strict sense, and when membership of a class is hereditary, we may speak of€™ castes.€™ It is perhaps a matter of doubt whether we should agree in regarding differences of interest as a separate form of social differentiation. It seems possible to resolve most of the examples here given of difference in interest into differences of function, rank, or culture. However that may be, there is clearly a close correlation between these various forms of social differentiation. A man€™s function will tend to carry with it a certain rank and a certain culture. Prof. North divides the factors which bring about social diffejnces into the social and the biological. To the latter he gives full weight. He thinks that slight but definite differences in intelligence exist between the average representatives of those per forming various functions, and that considerable inherited differences exist between the true functioning groups on one hand and the pauper, thrift- less, and criminal groups on the other. In this opinion he is probably justified. It may be remarked that this factor is becoming of greater importance. Modern society is elaborating a mechanism in the form of the educational ladder and vocational guidance whereby the young are being sifted and allocated to the functions they are most fitted to fulfil. Those engaged upon the improvement, of this mechanism are wont to have us believe that there lies the path to social salvation. Everyone will be happy in his job and no one will envy anyone else, because it will be realised that those performing any given function are the best fitted for the job. This rosy picture is apt to be marred by the reflection that the capacities of the members of society may not be fitted to the functions. There may not be enough people, for example, innately suited to the routine which industry demands. Account also has to be taken of the fact that inclination by no means always corresponds to capacity. All those who think themselves fitted to rule are not qualified to do so.Quite apart from these reflections, however, it may be seriously questioned whether, at least so long as rank differences persist, this biological sifting of the population is not likely to result in a dangerous segregation of the gifted members, dangerous to them and to those from whom they are separated, because there is sufficient common ground of humanity to make contact desirable, and dangerous to society because of the possible loss of the gifted through revolution or differential fertility. Whatever may be the causes of social differentiation, its existence is of the utmost importance. Certain forms of social differentiation, chiefly those of rank, may bring unrest and sometimes revolution. For differences of rank there is little favourable to be said. On the other hand, without differences in function and culture, there is the danger of stagnation if not of decay. Functional differences may nevertheless result in unhealthy specialisation, as is the case with regard to the divorce betwoen work by brain and work by hand to-day. The profoundly interesting study recently pub. lished by Rostovtzeff of the social and economic conditions in the Roman Empire seems to point to the conclusion that the decay of that civilisation was due to the failure to compose differences that Prof. North would call differences of rank; these led in the third century to convulsions to which an end was put by the fatal policy of the fourth century which enforced too great a uniformity.Difficulties arising from differences of rank trouble modern society. The Russian solution seems to take the form of enforcing a uniformity which may be worse than the disease. There is no more urgent task than an examination of social differentiation in modern communities, with the object of ascertaining what differences are desirable and stimulating and what differences merely cause friction if nothing worse. Only when we have a clearer view than we possess at present of the functioning of society can we hope to apply rational control and so hope to pass beyond our present

ISSN:0028-0836    

DOI:10.1038/120833a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THIS twenty-second volume of the €œHandbuch der, Physik€ is divided into, six chapters dealing respectively with electrons, atomic nuclei, radioactivity, the ions in gases, size and structure of molecules, and the natural system of the chemical elements. The treatment is exceedingly clear and complete, and the twelve contributors deserve high praise both for the excellence of the subject matter and for the successful way in which they have avoided overlapping. The production of the book, too, leaves nothing to be desired, and is worthy of the high standard we have growii to expect from Julius Springer. The numerous diagrams are uniform and very clear, and apart from the usual subdivisions of the chapters and sections of the book, a useful feature is the statement at the head of each page of the actual topic under discussion. A brief subject-index is given at the end of the volume, and a useful table of physical constants is included. W. Gerlach presents, in Chap. i., an authoritative account of the various methods which have been used for the deterniiriation of the charge and specific charge of the electron, the principles and theory of each method being very clearly stated. The various results are critically discussed and the most probable values given. In his discussion of Ehrenhaft€™s work the author concludes that the evidence is opposed to the existence of the sub-electron.InChap. ii., Kurt Philipp describes the theory and experimental verification of the scattering of a-rays in their passage through matter, as well as the scattering of /3- and X-rays. Determinations of the nuclear charge both by these methods and by the application of Moseley€™s law lead to the same results. This is followed by a brief account of the evaluation of the mass of atomic nuclei by the methods of J. J. Thomson, Aston, and €˜Dempster. 0. Hahn describes the experimental work by virtue of which the identity of the ce-particle with the helium nucleus was established, and Lise Meitner shows how we may gain information on nuclear structure from a study of Geiger and Nuttall€™s law, from the regularities observed in the emission of radiations by successive radioelements, and from the consideration of /3- and y-ray spectra. The chapter closes with an illuminating account by Kirsch and Pettersson of work on atomic disruption by bombardment with a-particles. The chapter on radioactivity, though brief, contains a valuable summary of the subject in its many aspects. In the section on radioactive disintegration, W. Bothe describes the general theory of disintegration and the most important cases of successive change which arise in practice. We are then introducd to the work on the experimental verification of the theory, with special reference to fluctuations, and this is followed by an outline of the principal methods used in determining the main constants of radioactive change. On pp. 143 and 218, perhaps too much stress has been laid on the calculated heat production due to radium and its products, for although the aggregate value approximately agrees with experiment, the constituent values differ appreciably from the recent experimental determinations by Gurney and by Ellis and Wooster respectively of the values to be attributed to the /3- and y-rays.The various methods in use for detecting and measuring the activities of radioactive substances are admirably summarised by Stefan Meyer, who also deals with the preparation and main properties of each of the products in the three disintegration series, and gives a useful summary in tabular form of the constants of the radioelements. The application of the radioelements as indicators has been found of great service in a variety of chemical and physico-chemical investigations, and the results are ably summarised by 0. Hahn, who also deals with the significance of radioactivity in the elucidation of problems connected with earth history. The calculation of the influence of radioactive heat on the cooling of the earth, given on p. 295, is due to Holmes, however, and not to Ingersoll and Zobel. Work on the thermal effect of potassium appeared too late to be included on p. 292, and we believe that the unsuitability of thorium minerals for age determinations (p. 302) is more satisfactorily explained on the basis of a recent paper by Holmes (Phil. Mag., vol. i. p. 1066; 1926) than by the proposal put forward in 1917 by Lawson. Chap. iv. contains a most valuable account of the ions in gases by Karl Przibram. After a his- torical introduction , an account is given of the main properties of an ionised gas, together with their theoretical interpretation. Next follows a very clear description of the (lifferent experimental methods and underlying theory for the determination of ionic mobilities, and of the influence of various factors such as pressure, temperature, and strength of field. The ionic mobility in gaseous mixtures is also discussed, and reference made to the abnormally high and low mobilities obtained under certain conditions. A section is devoted to the diffusion, recombination, and adsorption of ions, and the discussion of the kinetic theory of ionic constants is particularly welcome, for there are still many discrepancies between theory and experiment. Finally, after dealing with the charge, radius, and mass of ions, the chapter concludes with an account of the ionic wind, and the condensation of vapours on ions.Karl F. Herzfeld is to be congratulated on his eminently readable and full treatment of the size and structure of molecules in Chap. v. In little more than one hundred pages the divers data are skilfully woven into a consistent scheme, and an interesting introduction is followed successively by an account of the methods used, and their results, of the position of the atomic nuclei in the molecule, and of the evidence on the structure of the electron shells. The last two sections of this chapter are by H. G. Grimm, and deal lucidly with molecular volumes, the size of ions and its relation to ordinal number, and with atomic volumes and dimensions. To have collected together successfully material of such variety must have been no easy task, and little of importance appears to have been overlooked. Attention may perhaps be directed to the fact that in the section on thin films only one of Adam€™s numerous papers in the Proceedings of the Royal Society is quoted. The concluding chapter iii the book is a useful and well-written statement of our knowledge on the natural system of the chemical elements, by Fritz Paneth. He deals in turn with periodic and non- periodic properties, isotopy and the separation of isotopes, the distribution of the elements and atomic types in Nature, natural and artificial disintegration of the elements, and finally, with the interpretation of the experimental results from the viewpoint of the Rutherford-Bohr mode

ISSN:0028-0836    

DOI:10.1038/120834a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THE merits of a book on atomic and molecular structure can be judged by a very simple test. If the book merely gives an account of the personal views and impressions of the author, in the form of a long essay on valency, its value is probably not very great; but if it is written with a full sense of historic values, and is based at every point on the study of the original sources, the narrative immediately becomes of permanent value as a guide to the serious student of science. It is, therefore, a pleasure to find that Dr. Butler has shown no desire to €˜ push €˜ his own views on valency, but, on the contrary, has made a very successful effort to show precisely what was done by Dalton, Davy, Berzclius, Faraday, Frankland, Arrhenius, Werier, Thomson, Rutherford, Bohr, and the Braggs. In many cases he has cited the exact words of the author, and in a still larger number of cases he has shown in a diagram the apparatus that was used in those crucial tests which will be regarded in the future as classics €˜ of experimental research.As a result, the reader is able to follow step by step the logical stages by which modern theories have been suggested, tested, and established. This careful reproduction of original material has the further merit of making the book useful not only to the elementary student, who may be receiving a first introduction to theories of atomic and molecular structure, but also to many advanced students, whose second-hand knowledge of the subject may be too sketchy to be adequate. In addition to ten chapters of text and an epi. logue, the book contains two appendices, the first dealing with €œThe Structure of Crystals,€ whilst the second is in the form of a Periodic Table of the Elements, showing Arrangement of Electrons i

ISSN:0028-0836    

DOI:10.1038/120836b0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

ALTHOUGH Prof Planck€™s €œThermodynamics€ first appeared thirty years ago, it remains still one of the clearest books on the subject at the present day. The eighth edition has 17 sections and about 40 pages more than the first, but the sections up to 280 are numbered as before. The additional sections deal with Nernst€™s theorem and its consequences. T is now used for the absolute temperatur§ instead of , certain proofs formerly based on the properties of a perfect gas have been made general, and the treatment of electrolytes has been improved. The new edition is well printed, but the paper of it compares unfavourably with that of the first

ISSN:0028-0836    

DOI:10.1038/120837d0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THE work of Aston has shown that potassium, which has an atomic weight of 39·104 (Hönigschmid), is a mixture of two isotopes. The atomic masses of these are 39 and 41, and they are present in ordinary potassium in the proportion of 20 to 1 respectively. Potassium emits a fairly penetrating β-radiation, and we are led to inquire as to which of the isotopes iS responsible for the emission of β-rays. It may be that there is a third isotope present in potassium, but in such small amounts that its detection by the mass spectograph is impracticable. Such a possibility has been discussed by Harkins (Proc. Nat. Acad. Sci., vol. 11, p. 630; 1925), who considers that isotopes of mass 40 or 41, the former of which is unknown, are the ones most likely toe radioactive. Harkins considers the hypothetical isotope of mass 43 (Kossel:Phys. Zeit., vol. 20; 1919) to be less probable.We can arrive at a solution of the problem by carrying out a partial separation of the isotopes of potassium and examining the activities of the fractions obtained. By way of illustration we may suppose that such a partial separation leads to a concentration of the isotope 41, and that the atomic weight of the €˜ heavy €˜ fraction is found to be 0005 unit greater than that of ordinary potassium. The obvious conclusion from such a result would be that whereas ordinary potassium contains 520 per cent. of potassium 41, the €˜ heavy €˜ fraction contains 5.45 per cent. of that isotope. If the radioactivity of potassium is to be ascribed to the isotope of mass 41, we should then expect to find that the activity of the €˜ heavy €˜ fraction would be 48 per cent. greater than that of ordinary potassium. Should the activity be due to a hypothetical isotope of mass 43, the difference in activity would be -4/2 X 48 per cent. On the other hand, if the activity be attributable to the chief isotope of mass 39, we should find that the heavy fraction would be 02 per cent. less active than ordinary potassium. Shortly after they were successful in effecting a partial separation of the isotopes of mercury and of chlorine, by the method of ideal distillation, Brnsted and the present writer undertook an elaborate research on tlEie separation of the isotopes of potassium. After several unsuccessful attempts the work was discontinued, as we were engaged on other more pressing problems. It was taken up again later by one of us (G. H.) in collaboration with Miss L˜gstrup.About one litre of molten potassium was introduced into the first of a system of Pyrex bulbs connected to a high vacuum, By means of an electric heater and an asbestos cylinder containing carbon dioxide snow the potassium could be distilled from the lower to the upper half of the bulb, and in this way repeated distillations were carried out, the apparatus being maintained at a high vacuum all the time. The later operations of ideal distillation were per. formed in the succeeding bulbs, the carefully purified liquid potassium being heated to about 160° C. and the cooled potassium surface on which condensation was to take place being cooled by solid carbon dioxide. It was arranged that the distance between the hot and cold surfaces was maintained at less than 1 em. After each operation of ideal distillation about 1 . 2 cc, of potassium residue remained, and this was transferred (in vacuo) to the next bulb. This operation was repeated ten times, and the whole of the residual heavy fractions were collected to- gether so as to have ample material for an atomic weight determination. Full details of the distillation process will be published elsewhere. Prof. Honigschmid kindly undertook to determine the atomic weight of the residual heavy potassium fraction, and for this he found an atomic weight 0005 ( L 1) unit in excess of that of ordinary potassium. It was now necessary to compare the activity of the heavy fraction with that of ordinary potassium. Owing to the feeble radioactivity of potassium great difficulty was experienced in obtaining a sufficiently high insulation of the 3-ray electroscope to ensure an exact comparison of the two activities, and ultimately it was decided to abandon this method in favour of the Hoffmann vacuum electrometer. Through the courtesy of Prof 0. Hoffmann the measurements were carried out in his laboratory at Konigsberg. The difference between the activities of the heavy potassium fraction and ordinary potassium was found to be 42± 07 per cent. In each case the material was converted into potassium chloride for the purpose of measurement, This result is in good agreement with that to be expected from the observed change in atomic weight, on the assumption that the activity of potassium is due to the isotope of mass 4 1 . We are thus led to the conclusion that the potassium isotope 41 is mainly if not solely responsible for the observed radioactivity of potassium.If we make the assumption that in the ease of rubidium the activity is also due to the heavier of the two isotopes 85 and 87, we get a simple general explanation of the greater intensity of the activity of rubidium as compared with potassium. The heavier isotope is four times more strongly represented in rubidium than in potassium, and hence the total activity of rubidium is approximately four times that of potassium. On the other hand, ciesium is a pure element, and the absence of radioactivity in the case of this element can readily be explained by similar reasoning, as suggested by Aston some time ago (Ann. Rep. Chem. Soc., vol. 21, p. 258; 1924). According to Holmes and Lawson (NATURE, vol. 117, p. 620; 1926) the most probable half-value period of potassium is TK 15 x 1012 years. This value was obtained on the basis of very careful and detailed considerations of the relative f - ray activities of potassium, rubidium, and uranium, and by assuming that both the isotopes 39 and 41, i.e. the whole of ordinary potassium, are radioactive. Should the radioactivity be confined to the 41 constituent of the mixed element, it was shown that the half-value period of the isotope of mass 41 would be 75 x 1010 years (Holmes and Lawson: Phil. Mag., vol. ii. p. 1224; 1926). Now it has been shown above that the radioactivity of potassium is to be ascribed to the isotope 41, so that the latter figure for the half- period is the true one. Radioactive measurements give no indication of the period of the common potassium isotope of mass 39, and this does not appear to differ from other stable elements in respect of its radioactivity.The above conclusions in no way affect the interesting results obtained by Holmes and Lawson (Phil. Mag., lc.) on the radioactivity of potassium and its geological significance. From the calculated period of potassium 41 it follows that since the consolidation of the earth€™s crust about 2 per cent. of this isotope will have disintegrated, and we are led to the conclusion that at that early stage of the earth€™s history the atomic weight of potassium would be 0002 of a unit higher than it is to-day. Should they lack other methods, chemists of the very distant future will be able, by redetermining its atomic weight, to calculate the lapse of time since the first modern atomic weight determination of potassium. If we assume that the emission of p-particles effects an alteration in the nuclear charge, the product of transformation of potassium will be a calcium isotope of atomic weight 41. We have seen that since the consolidation of the earth€™s crust about 2 per cent. of potassium of mass 41 will have decayed, so that the maximum amount of calcium 41 which has accumulated in potassium minerals during the whole of geological time will amount to only O1 per cent. of their potassium content. This should be capable of detection in determinations of the atomic weight of calcium which has been extracted fro

ISSN:0028-0836    

DOI:10.1038/120838a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

IT has been clearly recognised that the force of gravity acting on the atmosphere of the earth will cause the heavier gases to settle downward by diffusion and the lighter gases to rise to the higher altitude, and that winds, if they exist, would by convection keep the composition of the air uniform at all elevations. The classical ideas of atmospheric pressures (for example, Humphreys, Jeans, Chapman, and Mime, etc.) have been based on the assumption that convection is negligible, at least above a 50 km. level, and that diffusion is the important factor in deter- mining the partial pressures of the gases. In this note are presented some conclusions, to be published in detail later, which have resulted from taking into account convection and diurnal temperature variations in the high atmosphere.The ordinary equations of diffusion show at once that if the air were uniformly mixed at all altitudes and then left free from all convection currents, there would be a constant flow of lighter molecules upward and of heavier molecules downward, which would be independent of the altitude until a level was reached where the diffusing gas would be in gravity equilibrium. This €˜ diffusion €˜ level for hydrogen would move from infinity down to 142 km. in one day, at the end of five days it would be at a height of 127 km, and in 50 days it would be at 113 km. The corresponding levels for helium would be at 137, 120, and 106 km. respectively. The new calculations give hydrogen and helium contents above 150 km. roughly 1/100,000 of the values previously calculated. Absorption of solar and terrestrial radiation must be taken into account in any discussion of radiation equilibrium in the upper atmosphere. Numerous writers have recognised this fact, but apparently none of them has made an attempt to calculate absorption coefficients or to estimate a difference of temperature for day and night, or winter and summer conditions. Water vapour above 11 km. absorbs a little more than 20 per cent. of black body radiation from below at earth temperatures, while carbon dioxide absorbs nearly 40 per cent. Ozone absorbs only about 2 per cent., but its presence is important because it absorbs about 4 per cent. of the solar radiation at an altitude where most of the re-radiation must be by the ozone itself. Temperature calculations based on these absorption coefficients show that for a 50° latitude above a height of 60 km. we should expect a tern- perature of about 250° K. during a winter day with a drop to 220° during the night, and a temperature of 370° during a summer day with a corresponding drop to 230° during the night.The atmosphere at the base of the stratosphere cannot be in radiation equilibrium, but must receive more radiant energy than it loses both from above and below during a 24-hour day. The temperature condition of the earth€™s surface is in very unstable equilibrium. The loss in heat by radiation from the warm equator is much less than from the cooler polar regions. An increase in temperature at sea-level near the equator would not result in an increase in the energy lost by radiation from these regions, but would actually result in a decrease. Loss of heat by radiation from the earth depends not on the condition of the surface, but on the temperature at the base of the stratosphere and absorption in the stratosphere. A slight change in the carbon dioxide of the air would have a tremendous influence on the climate of the earth. If the carbon dioxide content of the air were increased from the present 003 per cent. to 0 1 per cent., tropical plants would probably grow in the polar regions. On the other hand, if this protecting sheet decreased from 003 per cent. to 001 per cent., ice would probably be found near the equator. Since the present theory leads to low densities of the atmosphere above heights of 100 km. or so, densities much lower than those of classical tables, the facts about the appearances of meteors require explanation. It seems possible to do this following to a certain extent the ideas of Sparrow and departing from those of Lindemann. When a high-speed meteor strikes an air molecule, it is assumed that the energy of the impact violently ejects atoms, molecules, and possibly small particles of molecular dimensions from the body of the meteor. This ejected material, by virtue of its velocity, carries into the air the energy which eventually gives the light of the meteor trail. For example, when a nitrogen molecule strikes an iron meteor which has a velocity of 40 km. per second, the energy of the impact is sufficient to raise the temperature of 1800 molecules 1000° C., or to evaporate 56 molecules of iron, or to evaporate and ionise 24 molecules of iron. As a result of this impact, a mass roughly thirty times that of the nitrogen molecule is ejected from the meteor principally in the form of highly energised iron atoms which have velocities slightly greater than that of the meteor itself. The inelastic collisions of these iron atoms with the mole- cules of the air result in the visible trail.The excitation energy of these collisions may be as high as 155 volts for nitrogen or 280 volts for argon. Much of this energy may be radiated in the ultra- violet or even soft X-ray region, and it is probable that not more than one-tenth of the total radiation is in the visible part of the spectrum. Therefore, the total mass of the meteor must be much more than that derived by Lindemann and Dobson from their considerations of the relation between the mass of a meteor and its light. The temperature changes in the upper atmosphere from evening to morning, and from winter to summer, given by the present theory, lead one to expect appearance of meteors at heights which are greater by, say, 5 km. in the evening than in the morning, and in the summer than in the winter. It would be interesting to know whether this difference has be

ISSN:0028-0836    

DOI:10.1038/120839a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THE following seems to be a possible means of investigating the question of association. Without going into the experimental and mechanical difficulties, which are great but not insuperable, I will indicate briefly the general idea, and for that purpose will take the simplest optical system of several that might be used.Consider a liquid contained in a tubular cell which is closed at the top by a semi-platinised plate and by a mirror at the bottom: with proper adjustment we shall observe a system of interference rings centred about the vertical axis of the cell. Let the cell be mounted as a centrifuge and be fitted so that the speed of rotation, which is to be completely controllable, is known.It is clear that on rotation there will be a movement of the rings across the field of view. Assuming that both the number of rings and the rate at which they pass can be noted, we get a complete insight into the changes in the €˜ optical density €˜ of the liquid. Knowing the speed of rotation and the compressibility of the liquid, we can calculate its bulk density at any point on the radius of the cell.There are three cases to be considered. (1) With a pure unassociated liquid we may take it that the calculated bulk density is reached practically instantaneously, so that even while the speed is changing it will coincide with the optical density.(2) With a dilute solution the two densities will no longer coincide. The compressing effect will, as before, be instantaneous, but the difference between the two densities will, while the speed is changing, ho dependent on the osmotic pressure and the rate of diffusion of the solute. Obviously the slower the rate of change of speed the less the discrepancy. When the steady state at any constant speed has been reached, the difference will be a measure of the concentration of the solute. Thus it would seem that a solution can be distinguished from a pure liquid by seeing whether the rings continue to move after the constant speed is reached.(3) With concentrated solutions, the effects are more complicated, but they need not concern us here. Now it is easy to show that an associated liquid is but a special case of miscible liquids, and as such is subject to all the osmotic laws. If we select a liquid which is but slightly associated it would come under category (2), and, on centrifuging, the two sets of molecules would, in general, be temporarily separated; and if we know from other sources their relative con- centration, valuable light on the type of association might be obtained.It may be pointed out that the sensitiveness of the method is, among other things, proportional (approximately) to the depth of liquid under examination; thus using a long column and a suitable optical system it might be possible to separate isotopes which are not otherwise separable. As bearing on the whole subject I would direct attention to a paper by the late Dr. C. V. Burton and me on the €œosmotic theory of solutions€ (Phil. Mag., 1909, p. 598; there are printer€™s errors on p., 612), which may help in the matter; indeed, the opti¢al method mdi- cated above was devised by us so as to continue the centrifuging experiments mentioned therein; but I am not in a position to pursue the research any further.Since writing the above I have seen Messrs. Raman and Krishnan€™s letter on €œThe Maxwell Effect in Liquids€ (NATURE, Nov. 19). It would be interesting to see whether the €˜optical€™ centrifuge could be used to test their theory; if, however, it takes time for asymmetric molecules to orient themselves, it will be difficult to distinguish between this effect and that c

ISSN:0028-0836    

DOI:10.1038/120840b0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

RECENT investigations on the band spectrum of helium and the many-lined spectrum of hydrogen seem to show that there is a far-reaching analogy between the arrangement and location of the electronic states of the term systems of the spectra of He, He2, and H2. For the spectra of He and He2this analogy has been discussed by Mullikan (Proc. Nat. Acad. Sci.,12, 158; 1925) and extended by the author (Proc. Nat.Acad. Sci.,13,213; 1927). In regard to the correspondence between the electronic states of He and H2, Richardson demonstrated a remarkable agree-ment between the term values (see Table I.) of certain band groups of the many lined spectrum of H2which he analysed (Proc. Roy. Soc.,113, 400; 1926) and the triplet system of the atomic helium spectrum In the case of He2and H2the analogy can be carried further in detail, due to the fact that under the usual conditions of excitation the band groups of the triplet system of He2(‘Main-series’) and the corresponding groups in the many lined spectrum of hydrogen (Fuicher bands, etc., seeProc. Roy. Soc.,113, 368; 1926) appear in greater intensity than the band groups of the singlet system of He2(‘Second series’) and the corresponding groups of the many - lined spectrum of H2. Furthermore, there appear relatively many lines in theQ-branches of the band spectrum of He2and in the many-lined spectrum of H2, while theP- andR-branches fade out with comparatively low rotational quantum numbers.Table I. gives a summary of the arrangement and magnitude of such of the electronic terms (in effective quantum numbers) of the spectra of He2, He, and H2 as have been analysed. The existence of the well-known 2S state in theTABLE I. OBSERVED EFFECTIVE QUANTUM NUMBERS OF ELECTRONIC STATES IN HELIUM AND HYDROQEN.Triplet System. Singlet System.D. S. He-Atom.H2-Molecule. IIe,-Molecule.He-Atom. 12 34 56 ..1788 (1928)* .. 2810 2928 30133818 3928 .. .. 4928 .... 5927 .. etc.1689 1937 .. 2697 2933 29973700 3932 3997 4701 4932 4997.. etc. .. 1934 (1.928)*.. 2937 .. 3939.. 4941 .. 5941etc. 07441853 .. .. 2964.. 3965 4966.. 5964 0744 .. ..1850 2009 .. 2857 3011 29983858 4011 3998 .. etc. .... .. 09191919 1695 (2920)* (2695.*.. . . .... * Calculated.helium spectrum, and the fact that intercombinations between the triplet and singlet systems mentioned in Table I. have not been observed (except for the combination X 59156 found by Lyman in the helium spectrum, which he classifies as the transition 1180 2P1) led me to look for a corresponding metastable state of H2 by absorption experiments in excited molecular hydrogen. The experimental conditions in the emission tube were chosen so as to produce the many-lined spectrum in J)articular. In the absorption tube a weak electric excitation of the hydrogen gas was used in order to excite any existing metastable states, that these might be the initial states of absorption for the radiation of the H2-molecules in the emission tube. If there is any absorption it should be shown by self-reversal of certain band lines. The absorption measurements which have been made over the whole region of the visible many- lined spectrum seem, indeed, to have the expected result. A number of intense lines, which are not distributed over the whole spectrum but are located in definitely . bounded regions, distinctly show self- reversal, while other intense lines scattered over the whole spectrum do not show any absorption. The study of the series relations of the reversed lines is in progress. After further experiments the results will be published elsewhere in detail. It is intended to extend the absorption experiments to excited molecular

ISSN:0028-0836    

DOI:10.1038/120841a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature