摘要:

THE Materials Policy Commission, established by President Truman on January 22, 1951, to make a long-range study of the materials problem of the United States, having regard to the needs and resources of friendly nations, was also charged with assisting the formulation of materials policy. The Commission was assisted by a comprehensive staff, as well as by a panel of the National Research Council and by numerous industrial firms, universities and other bodies. The work of the Commission has now been made available in a comprehensive report* running to five volumes, of which the first, entitled "Foundations for Growth and Security", embodies the bulk of the findings and recommendations, con-stituting a summary and broad analysis of the whole problem. With the fourth volume, "The Promise of Technology", it is the part of the report of most interest to the scientific worker, though the tech-nologist will also be concerned with the second and third volumes, dealing with the outlook for key commodities and energy sources, respectively. The fifth volume presents a few of the basic studies prepared to assist the Commission. The report of this Commission, known from its chairman, Mr. W. S. Paley, as the Paley Commission, was sent to Congress on July 1, 1951, and ^the National Security Resources Board was asked by President Truman to study the Commission's seventy-eight specific recommendations. A special body was set up by that Board to submit sug-gestions for implementing those recommendations as well as to assist in continuing the review of materials and energy policies and programmes. Originally the proposals of the National Security Resources Board were to be forthcoming within sixty days ; but this task proved too great for the original time limit. Nevertheless, the report of the Materials Policy Commission seems likely to result in definite action by the United States Government.One of the most interesting features of the report is, however, the way it endorses an opinion expressed earlier in the year in "Facts and Figures for the Chemical Process Industries" by E. W. Pehrson, of the United States Bureau of Mines, that, from a mineral point of view, the United States are a 'have-not' nation in several indispensable minerals, and that for some of these the United States cannot hope to improve their position significantly through increased domestic output. Pehrson, in this article, listed thirty-eight important natural raw materials, and showed that in only nine of these are the United States self-sufficient, and for twelve they produce only ten per cent or less of their needs. The Paley Commission, in the first volume of its report, lists the production and reserves of twenty-two key materials in the free world, on all of which the United States are already substantially reliant or likely to become more reliant. Furthermore, with but 6-3 per cent of the world's population, the United States use 45 per cent of the world's minerals and are responsible for 50 per cent of the world's industrial output. During the first fifty years of this century, the population of the United States has doubled, while the national output increased five times. While the consumption of agricultural products of all kinds, including food, increased two and a quarter times, the consumption of minerals, including fuels, increased sixfold. By 1950, in comparison with 1900, the output of coal had increased two and a half times, of copper three times, of iron ore three and a half times, of zinc four times, of natural gas twenty-sixfold, and of crude oil thirbyfold. This trend is expected to con-tinue. It is estimated that by 1975 the demand for minerals as a whole will be twice as heavy as in 1950, though it is difficult to forecast the increased demand for any particular material.To readers of the report outside the United States the most interesting feature, however, in its analysis of the materials situation is not the realization by the United States of the worsening relationship between their requirements and their means of satisfy-ing them, but rather the outlook revealed by the Commission. There is official recognition that supplies are not inexhaustible, that even the United States must learn to be less wasteful of their natural resources of minerals, great as they are, and must accept the necessity of re-using the products of those resources many times over, and improve their techniques for the discovery and development of mineral resources. The Paley Commission points out that by making fuller use of known resources either by the avoidance of wastes, the exploitation of materials of lower grade or quality, or the utilization of waste products, the supplies of domestic materials can be expanded. This is largely a matter of expanding technology, though new physical knowledge may also be required. Both factors contribute to the improvement which could result by shifting from the use of scarce to more abundant materials, or the more economical use of materials which comes when they are used under conditions having closer regard alike to their intrinsic properties and to the purpose to be served. Whatever advantage can be drawn from the synthesis of new materials to relieve existing shortages, the recovery of valuable materials from waste products or scrap, the prevention of corrosion and the reduction of losses in storage or transport depend on tech-nological skill and scientific knowledge. Furthermore, they may also determine the capacity of the United States for dealing with what the Commission describes as the real threat in their materials problem.This threat does not relate to absolute shortages but is due to the insidiously rising real coststhe hours of human work and amounts of capital required to bring a pound of industrial material or a unit of energy into useful form. During most of the twentieth century these real costs of materials have been declining, and this decline has assisted in raising standards of living in the United States. The Paley Commission believes that this trend has now been retarded, sometimes stopped and even reversed. The central challenge of the materials problem in the United States is accordingly to meet expanding demands with expanding supplies, while averting a rise in real costs per unit. This question of costs is manifestly likely to be more difficult to overcome than in the past. Only in chemicals have real costs apparently declined faster in the past decade than in the previous four ; and whereas wholesale prices of commodities in general advanced about 105 per cent between 1940 and 1950, that of zinc rose 119 per cent, petroleum 149 per cent, farm products 152 per cent, lead 157 per cent and lumber 218 per cent. Other materials, including aluminium, iron ore, nickel, sulphur and copper, rose less than the general average. But the rate of technological progress, which could help to counteract this situation, depends largely on the supply of scientifically trained per-sonnel and the expansion of the fundamental scientific knowledge upon which technology is based ; here the Paley Commission states that available evidence shows that the prospective flow of scientific men- and engineers from the universities is alarmingly below apparent needs.The Commission accepts the view that the United States have been less assiduous in increasing the store of fundamental knowledge than in applying such knowledge in industry, and that fundamental research in the United States should be more in balance with the expenditure of effort on applied research and development. It does not believe, however, that the United States Government has a philosophy of research commensurate with its present respons-ibilities for the allocation of financial support. At no point in the government organization can a com-prehensive picture be obtained of the pattern of technological activity financed by the Government or an appraisal of that pattern.In general terms, the Commission formulates six main tasks for technology : the fostering of new techniques for discovery; the utilization of new materials ; the broader application of the principle of re-cycling ; the handling of low concentrations of useful materials; the development and more economic use of renewable resources, such as solar energy ; and the use of more-abundant materials to lessen or eliminate the use of a scarce material. These are dealt with in a subsequent chapter in the first volume, but detailed discussion is reserved for the fourth volume, in which specific problems are indicated. Here we can only consider the Commission's further judgment of the United States resources of trained man-power and their direction, which are examined in the chapter on "Government and Materials Research". The United States are estimated to have roughly 625,000 scientific workers and engineers, of whom some 76,000 scientists and 59,000 engineers are engaged in researchnearly 60 per cent in industrial laboratories, about 20 per cent in government laboratories and 20 per cent in educational institu-tions, scientific foundations, and the like. As already indicated, the Commission concurs in the view that there is likely to be an acute shortage of technical man-power in the immediate future, and it recommends that both industry and the government should give the maximum support to programmes for advanced training consistent with the number of young scientific workers willing and able to continue their work. It also recommends that the appropria-tion of the National Science Foundation should be increased to the limit of 15 million dollars which Congress inserted into its basic Act, and that Congress should re-examine the bases upon which it set this limit so low.The most pressing need, however, is for better co-ordination. The Commission believes that estab-lishment of an active co-ordinating body is essential for shaping and executing a comprehensive, effective national policy of materials research. Such an organization would estimate and appraise the impact of technology and other forces upon supply. It would, for example, revise continually estimates of reserves in the light of new discoveries and the development of new uses and methods ; estimate annually requirements of supplies at least ten years into the future on the basis of scientific and tech-nological developments, as well as data on domestic production and consumption, and imports and exports; report potential shortages of important materials far enough in advance to permit corrective action; and maintain an up-to-date list of the materials research and development projects that should be undertaken. For such projects that cannot normally be assumed by industry, it would consult with the appropriate advisory bodies and, if necessary, bring the problem before the President or Congress. Such an organization would necessarily occupy a high place in the structure of the Federal Government and maintain close relations with the National Science Foundation and many other government agencies as well as with industry. The Commission recommends that the National Security Resources Board should be directed to provide such a co-ordinating service. Whatever action may be taken on the Paley Com-mission's report in the United States cannot affect its value as a record of a reasonable appraisal of the situation over the next twenty-five years. Moreover, although in the lineage of Vannevar Bush's "Science, the Endless Frontier" and the Steelman report on "Science and Public Policy", it does more than record the view that the United States should be increasingly concerned with the conservation of resources : it asserts that the problem is one for the free world as a whole, and in which international co-operation is indispensable. The major premise of the report is, in fact, that the oveiall objective of a national materials policy for the United States should be to ensure an adequate and dependable flow of materials at the lowest cost consistent with national security and with the welfare of friendly nations. The Commission recommends that increasing emphasis be given under the United States programmes of technical assistance to under-developed areas for geological survey, preliminary exploration, and advice on mining technology. Support for these programmes should be increased to as much as four million dollars a year ; but the extension of technical assistance in these fields should be accompanied by assurances to the United States that the recipient country will promote conditions favourable to developing such resources as may be discovered.This objective inquiry has thus summoned the United States to conserve natural resources and co-ordinate them along with those of the other free natiorfe to the ends of common growth, common safety and common welfare, almost simultaneously with Prof. A. V. Hill's reference to this question of world resources and world population in his presi-dential address to the British Association. Prof. Hill emphasized the challenge of the present situation to the responsible use of knowledge and the combined resources of science, humanity and statesmanship. The Paley Commission affirms its belief in the prin-ciple of growth and in private enterprise as the most effective means of performing industrial tasks in the United States ; but it believes also that the destinies of the United States are inextricably bound up with those of the free world. There is much technical detail of wide interest to be found in these reports, but there is nothing more encouraging or more widely welcome than the evidence they contain of this spirit of co-operation and of readiness to approach the common problem of raising the standards of living of the free world as a whole, responsibly and imagin-atively, with all the resources which science and technology can put at the disposal of statesmanship.Resources for Freedom. (A Report to the President bv the President's Materials Policy Commission.) Vol. 1 : Foundations for Growth and Security. Pp. viii+184. 1.25 dollars. Vol. 4: The Promise of Technology. Pp. x+228. 1.75 dollars. (Washington, B.C.: Government Printing Office, 1952.)

ISSN:0028-0836    

DOI:10.1038/171001a0

出版商:Nature Publishing Group    

年代:1953

数据来源: Nature

摘要:

PROF. W. M. SMART has written this book for the general educated reader, who, in the first part, will find an admirably descriptive account of the solar system, which is complete in itself. The material is presented so as to lead up to the con-clusion that the uniformities of orbital and rotational motions in the solar system are so pronounced as to make it very probable that the whole system must have come into being as the result of a single cosmical process. There are exceptions to these uniformities, the most striking being the existence of retrograde satellites. But there is a rational explanation ; it is significant that the retrograde satellites are mainly to be found at the outermost fringes of the planetary systems concerned. To quote Prof. Smart : "There is perhaps a little justification for the suggestion that the satellites not conforming to the majority rule may have been originally minor planets which, through the interplay of planetary and other attractions, have been captured by the parent planets". Having decided that the solar system originated as the result of a single cosmical process, the next question is : When did this happen? The second part of the book is devoted to the answer to this question, and an obvious starting-point is the age of the earth. Prof. Smart recalls the nineteenth-century controversy between Kelvin and the geologists, and he then gives an excellent resume of the main facts of radioactive and nuclear phenomena, leading up to a clear account of the radioactive method of determining the age of the earth's crust, which is tied down to something between two and four thousand million years. He then passes on to an accoiint of the astronomical evidence which leads to estimates of the ages of the moon, sun and universe. The evidence from these phenomena of the expansion of the universe is outlined, leading to the conclusion that "we are left with a time scale of a few thousand million years within which the universe has reached its present development from an initial state of high concentration. The evidence from the lengthening of the day as a consequence of tidal friction leads to the conclusion that about 4,000 million years ago the moon's centre was bub 8,000 miles from the earth's centre, and that then the period of orbital revolution of the moon was equal to the rotational period of the earth, both being about 4 hours". The further sug-gestion seems to be unavoidable that the moon had then just been formed from the earth, from which it follows that the age of the moon is about 4,000 million years at most.As regards the age of the sun, Prof. Smart indicates how current ideas of the source of stellar energy lead to the conclusion that the sun's age "must then be much less than 8,000 million years". I feel that in this part of his book Prof. Smart may have produced an impression in the general reader's mind which is rather too dogmatic. He gives an admirable account of the known thermo-nuclear reactions which may have been effective in the life-history of the sun. But I think he could have made it clearer that our knowledge of these processes is probably incomplete and that other nuclear processes, of which at present we are ignorant, may have been effective. Until the method of synthesis of the more complex nuclei is understood, it is probably imprudent to be dogmatic. But having said this much, I hasten to add that the general reader will find a fascinating and well-written account of those thermo-nuclear reactions which have been studied and are now well understood. There remains the question of the exact mechanism of the cosmical process whereby the solar system was formed. The answer really is that we do not know, and in the third part of the book all that Prof. Smart can do is to give an account of the various theories that have been advanced. He records the conclusion that "the scientific search for an answer to our final question has thus failed, up to date, to reach a solution agreeable to astronomers other than those perhaps who individually are concerned with the formation of a particular theory". A very sound and salutary conclusion !The high standard of presentation is only what one expects from the Cambridge University Press. The book is excellently illustrated.

ISSN:0028-0836    

DOI:10.1038/171003a0

出版商:Nature Publishing Group    

年代:1953

数据来源: Nature

摘要:

PROF. C. VAN RIET LOWE, of the University of the Witwatersrand, Johannesburg, has won a great reputation among archaeologists for the work he has accomplished on the prehistory of South Africa. What then could be more fortunate than the collaboration of a man who knows as much as he does of the prehistory of the subcontinent with a colleague like Mr. E. J. Wayland, the director of the Geological Survey of Uganda?a man whose knowledge of his subject is unrivalled and who shares Prof. Lowe's love for prehistory ! Part 1 of Memoir No. 6 of the Geological Survey of Uganda has yet to appear, and in it Mr. Wayland will deal with the Pleistocene geology of the Uganda area ; it is to be hoped that he will not delay too long in publishing the fruits of his researches. Meanwhile, and happily, Part 2 ("Prehistory") of the Memoir has appeared, the result of some months of field- and museum-work in Uganda carried out in 1939 by Prof. Lowe, who worked at Mr. Wayland's sites with him and col-laborated very closely. The work is exactly what one could have hoped for?a straightforward and lucid account of the Stone Age cultures of Uganda based on the geological and archaeological investi-gations of Mr. Wayland. It is perhaps to be regretted that the author was unable, as he states, to examine an earlier work on the area?Mr. T. P. O'Brien's "The Prehistory of the Uganda Protectorate"?while he was working in the country. One questions whether a most understand-able desire to avoid entering the lists of East African prehistoric controversialists really does excuse the ignoring of this book ; for though O'Brien was not a geologist, he did have geological advice, including much kind help from Mr. Wayland, and had some experience in typology?and he did produce an impressive vohime. It was always clear that his presentation of the story was open to criticism ; in this case, for example, it would seem that Prof. Lowe does not agree with all his conclusions, such as the dating of the Kafuan culture ; but it would have been a great help to prehistorians who have not worked in Uganda to have had the criticisms of the work of Prof. Lowe's predecessor from the pen of one who does know the country.The memoir opens with a historical review?neces-sarily mainly an account of Wayland's connexion with Uganda. While not going into details, the geological setting is here given and, a little later, there is a diagrammatic section of the Kagera river valley near Nsongezi showing terraces and the 'M', 'N' and 'O' horizons. There are chapters on the various cultures, starting with the Kafuan and reviewing the African Chellean, the African Acheu-lean, the Sangoan,.and the Upper and Epi-palseolithic cultures and concluding with the Neolithic. In dealing with the Magosian culture, in the publication of which I was proud to be associated with Mr. Wayland in 1932, Prof. Lowe regrets that as all the material was sent to Cambridge he can only summarize the descriptions given in the paper referred to. There are thus no illustrations of the Magosian industry in this book?a notable lack in such a definitive work on the prehistory of the country. Yet reproduction of the original drawings or a choice re-drawing of the specimens could easily have been arranged. A brief but excellent summary and conclusions, with a useful table of climatic and geological correlations and, later, a bibliography, complete the text of 113 pages. Commenting on the surprising absence of any expression of the 'Capsio-Aurignacian complex' in Uganda, the author suggests that this may have been due to the lack of any fine-grained material such as flint, obsidian or indurated shale suitable for the manufacture of blade-and-burin industries. I have always felt that early man was very much at the mercy of physical Nature and feel sure that, as prehistorians discussing distribution maps, we often pay too little attention to this kind of circumstance. Lastly come fifty-four full quarto pages of illus-trations of stone industries. These are well-chosen and very well drawn, many of them from the gifted pen of Mrs. Leakey?and it is no easy matter to interpret specimens of fairly crude industries when they are made from coarse-grained materials lacking the clearly defined flake intersections of flint and similar materials. Altogether Prof, van Riet Lowe is to be heartily con-gratulated on having accomplished so much in his visits to Uganda (none of them very long), on having written a clear and much-needed account of the industries of the country founded on sound geological premises, and on having made available for study in the illustrations a large number of stone implements of various ages and cultures.

ISSN:0028-0836    

DOI:10.1038/171004a0

出版商:Nature Publishing Group    

年代:1953

数据来源: Nature

摘要:

THE storms that periodically affect the world of colour show few signs of abating, and a fresh disturbance from the west, indeed from as far west as California, is heralded by this monograph. Dr. G. L. Walls is already w^ell known as the author of "The Vertebrate Eye and its Adaptive Radiation", but the present work is in no sense a staid text-book. On the contrary, it is a trenchant criticism of many orthodox views and many orthodox workers, and perhaps we should be grateful that at least two British men of science in this field, Dr. W. S. Stiles and Dr. F. H. G. Pitt, emerge relatively un-scathed. For once, however, it is not the three-component theory of colour vision that is under attack. At the outset, the authors make it clear that they are staunch supporters of this theory, and, while their main theme concerns defective colour vision, it is their views on the yellow macular pigment that will probably create the greatest interest. A yellow pig-ment is believed by many authorities on vision to occupy the central macular area of the retina, and variations in its density are commonly regarded as a major cause of individual differences of colour per-ception and colour matching. The present authors do not actually deny the existence of the pigment, but they do deny that it plays the important part that is frequently attributed to it.A subjective demonstration of the macula is obtained when a uniform area of light such as the sky is viewed through a filter which transmits mainly at the far red and far violet ends of the spectrum. A diffusely defined reddish area is seen projected against the sky, and, as the gaze is directed from one part of the sky to another, so the spot follows the direction of view. It quickly disappears owing to local adaptation of the retina, but is restored to view if the filter is momentarily removed and then replaced. Sometimes the spot can be seen, without the aid of a filter, projected on a material dyed with a dichroic dye, although such dyes are normally avoided both because of their apparent spottiness and their marked change of colour with quality of the lighting. James Clerk Maxwell studied this spot in some detail, and it is often referred to as 'Maxwell's spot'. An obvious and commonly held explanation was absorption of the blue radiation by the yellow macular pigment, and it is this explanation that Walls and Mathews flatly reject. They have been to considerable trouble to discover a filter which shows the effect as clearly as possible, and, with the aid of an experimental Wratten filter, detailed structure within the spot can be observed. The structure varies considerably from observer to observer and even between the right and left eyes of a given observer, but most often a central red spot subtending about y is seen, and then an annular clearing of the same colour as the background, surrounded by a further red zone the diameter of which is some 3-4. Occasionally, a tiny pip of the colour of the background is located at the centre of the central spot, an effect I can see in my left eye using Walls's filter, but not in the right.Walls and Mathews point out with some logic that a yellow pigment impregnated in the retinal tissue could scarcely account for the structure of Maxwell's spot, since the retina is thinnest in the central | of the fovea in just the area where the blue absorption should be greatest. They therefore attribute the phenomenon to variations in distribution of the retinal colour receptors, and they point in particular to the recent experiments in foveal tritanopia (which they call tetartanopia) as evidence that the bluo receptors are missing in the foveal centre. A number of other arguments are assembled to demolish the macular hypothesis, including the dis-covery that one group of colour-defectives, the deuteranopes, are unable to see the Maxwell spot. The latter half of the monograph is, in fact, mainly devoted to a description of the spots seen by colour-defectives and to a discussion of the observation as a colour vision test.There is much here that deserves detailed study, and the analysis is undoubtedly made more difficult by the fact that in some respects both a yellow pigment and absence of blue receptors could produce rather similar effects. It does no harm for orthodoxy to be subject to the fierce criticism that we have here, but not all the arguments are equally valid. Many people would probably give greater weight to the histological arguments if reference had been made to Polyak's work. Then the authors criticize the use of data derived by calculation from the C.I.E. colori-metric system in place of direct experimental observations, yet their own neutral-point determina-tions were calculated on the C.I.E. chromaticity chart. Perhaps the main misinterpretation, however, is in attributing colour-matching differences to differences in receptor distribution. Two different physical stimuli that have the same colour would remain a match however much the proportions of red to green to blue receptors were changed in the area of the retina viewing the two lights. The appearance of the lights would change, but they would still match. On tho other hand, if the spectral sensitivities of the receptors were altered, or if a colour filter were introduced in the two beams, the match would break down. Actually, colour matches differ from one observer to another very much as if a yellow filter of differing density had been introduced, hence the argument for the yellow macular pigment.Yet difficulties do remain, and we can still be grateful to the authors of this monograph for their ruthless exposure of some of the fallacies of the pigmentary theory of Maxwell's spot without neces-sarily accepting all their arguments and conclusions.

ISSN:0028-0836    

DOI:10.1038/171005a0

出版商:Nature Publishing Group    

年代:1953

数据来源: Nature

摘要:

DESPITE (or perhaps because of) the rapid progress during the past twenty years in the elucidation of plant physiology, text-books in this field of natural knowledge have remained notoriously few and far between. The appearance of a new one is thus an event of unusual interest. This new volume, originating chiefly from the California Institute of Technology, is distinguished especially by the excellence of its treatment of the more biochemical aspects of the activities of the plant, and there are admirable chapters on photo-synthesis, carbohydrate metabolism, respiration, nitrogen metabolism and enzyme action. The capacity and enthusiasm of the authors are, however, by no means exhausted by their labours on nutrition and metabolism, as is shown when they proceed, in the last third of the book, to give a stimulating arid authoritative treatment of growth and development, in which the plant hormones, tissue culture and photoperiodism receive especial attention.In general the information provided is thoroughly up to date, and, though references are not cited in the text, a short list of sources is appended to each chapter. The book as a whole is written at a level approximating to that of a general degree course in botany, but in biochemical and some other aspects the standard of treatment is nearer to that of a special course. Omissions that may be noted include a failure to attempt an adequate explanation of root pressure, or to mention frequently observed phenomena such as guttation, nastic movements, haptotropism or nutation. Minor objection could be taken to a preliminary statement on p. 11, which might be interpreted to mean that the oxygen of photosynthesis originates from carbon dioxide the correct position on this is of course clearly indicated later in the chapter and also to a slight uncertainty in the text as to whether or not the authors intend photosynthesis to be reckoned as a part of the meta-bolism of the plant. In contrast with most other text-books on plant physiology, this one is copiously illustrated by means of drawings, diagrams, cartoons and graphs, to a total of 218. Many of these are excellent and some decidedly novel, such as that in which the familiar Askenasy apparatus is depicted as seen obliquely from above. But a few of the illustrations fall below the high standard set by the text. Fig. 11-9, pur-porting to illustrate the legume root nodule, is decidedly crude. The diagrams referring to plasmolysis fail to accord with the text in that they show no overall shrinkage in the size of the cell. The seedlings portrayed in Fig. 14-4 and stated to be "beans" seem more likely to be those of a cucurbit.These minor criticisms do not detract significantly from the assessment of this new work as a notable achievement. It is written in a lucid and interesting style, and is printed in a large, easily read type. A first reading has yielded only a single misprint. In so far as the rather high price permits of it, this text-book should be in the hands of all students reading for a general or special degree in botany.

ISSN:0028-0836    

DOI:10.1038/171006a0

出版商:Nature Publishing Group    

年代:1953

数据来源: Nature

摘要:

THE announcement of a synthetic soil conditioner, for the improvement of soil structure on a wide scale, was first made at a meeting of the American Association for the Advancement of Science held in Philadelphia on December 29, 1951, where a sym-posium on the improvement of soil structure by the application of organic matter took place. The papers read at this symposium have been published1, and I have given a summary of them2. The present article is intended to give some account of the development and properties of soil conditioners. Soil Organic Matter and Soil StructureThe organic matter of soil plays an essential part in securing in soil the structure that is required for high fertility. The maintenance of the supply of organic matter to arable soils is, indeed, a matter of the greatest economic importance, for productive capacity is largely dependent upon it. It is a well-known fact that an arable soil regularly supplied with farmyard manure has an improved and more stable structure than the same soil that has not received organic additives. A more friable crumb structure resistant to disintegration by water is produced. The organic matter of soil is primarily derived from the decomposition products of plants and from the products of autolysis of the immense numbers of micro-organisms which develop at the expense of substances of plant origin. A dynamic equilibrium exists in the soil between the numbers of bacteria, protozoa, yeasts and fungi, etc., that inhabit the soil and the organic matter being continually supplied by the decaying animal and vegetable tissues. Soil, therefore, normally contains a wide range of sub-stances commonly classed as metabolites of animal and plant tissues. The speeds of change of these substances may be very great, the rates depending on the temperature, hydrogen ion concentration, aeration, availability of water and mineral content of the soil. A number of substances, derived from animal, plant or microbiological life, are, however, relatively resistant to breakdown, and these sub-stances make up for the most part what is commonly known as organic matter. Such substances have the physical and chemical properties which together help to determine the structure and to influence the fertility of a soil.Among the most characteristic of the products making up the soil organic matter is the black colloidal material having high hydrophilic power known as humus. This is a complex mixture of substances which was once thought to be formed solely from the cellulose in soil but which is, in fact, a natural system varying in composition and con-sisting largely of various derivatives of lignins, proteins and celluloses. This organic matter greatly influences the structure of a soil, and therefore the air-water relationships upon which the fertility of a soil depends. The structure of a soil refers to the grouping or clustering of soil particles into aggregates or crumbs that at once influence water-movement, aeration and heat transfer. The granules that make up a soil of good structure may have a tremendous internal surface like that of a highly porous sponge, and it is in this large surface area that many of the biochemical and chemical changes take place that so markedly affect fertility. It is here where develop micro-organisms which convert organic nitrogenous com-pounds into the nitrate required by the plant roots, where metallic ions required by the plant are held by the soil in a base-exchangeable, or dissociable, form, where oxygen is dissolved and carbon dioxide is generated influencing local acidity and the meta-bolism of the plant root.Aggregating substances are found uniformly dis-tributed in soil crumbs. These consist8 of organic compounds resulting from the decomposition of fresh organic matter and of a group of substances, including oxides of iron and aluminium, fats, waxes and resins, which are less efficient than the former as soil aggregators. It is well known that bacterial slimes and fungal mycelia play an important part in soil aggregation and the resistance of soils to erosion. It is now known that among humus constituents are the polyuronides, substances related to the sugars and existing in a polymerized form. Forsyth4 has, for example, isolated from soil a polysaccharide fraction containing uronic acid units. These are widely distributed in plants, composts and soils. The quantity of polyuronide present in soil varies with the type of soil5, and there is evidence that the more fertile the soil the greater is the quantity of polyuronide present. Polyuronides include such well-known substances as pectic acid, alginic acid and a variety of bacterial polysaccharides. They compose the plant gums that are found in soils containing decaying vegetable matter. Bacterial polysaccharides such as the levans and dextrans also have marked aggregating effects on soils5'7.Alginic Acid and Soil Structure The large effect of a polyuronic acid, such as alginic acid, in increasing the water-holding power and crumb-stability of a soil was first shown by Quastel and Webley in 1947 B in work carried out during 1941-45 in the Agricultural Research Council Unit of Soil Metabolism at the Rothamsted Experi-mental Station, Harpenden. These investigators used a.manometric method of assessing the availability of oxygen to living cells, such as those provided by micro-organisms and plant roots, present in soils. The technique made it possible to investigate rapidly the immediate effects of the addition of various forms of organic matter on water-holding power and crumb-stability of soil. It was speedily found that the incorporation into soils of a variety of substances may greatly increase the amount of water that can be added to a soil before the availability of oxygen, defined as the aeration factor, falls. Sodium alggtnate, in particular, greatly increases both the wa^er-holcling power of a soil and ite crumb-stability. Results showing the effect of adding alginate to a standard soil depleted of organic matter are given in Table 1. It is seen that the addition of 1 per cent sodium alginate increases the aeration factor of a poor soil to that found for a fertile garden soil. The effect of the alginate rapidly increases to a maximum with increase of concentration. Even a garden soil, with a fairly high content of organic matter, showing good aeration at a high water-content, is affected by addition of alginate so as to improve the hydrophilic properties of the soil (Table 1).Table 1. AERATION FACTOKS OF SOILS CONTAINING ALGINATB AND OTHER SOIL CONDITIONERS (Quastel and Webley, ref. 8) Percentage water content per dry weight of soil25 37-5 50 62-5 Aeration factor values*Standard soil alone (a heavy clay) + 0-1% sodium alginate + 1 -0% sodium alginate 82-7 48-6 29-4 14-9 88-4 76-4 42-7 17-2 97-4 96-3 67-9 39-0Garden soil + 1-0% sodium alginate 101-0 83-2 72-0 21-7 108-4 112-0 123-4 96-0Standard soil alone + 1 % cellulose acetate -f- 1 % methyl cellulose + 1 % carboxymethylcellulose + 2% farmyard manure (dried and ground) + 2% horse dung + 2% ground peat + 2% extract of peat 4- 2% extract of garden soil 86-4 55-1 27-0 16-0 97-1 89-2 58-6 31-7 91-7 88-8 53-7 21-5 100-4 94-3 52-6 25-686-2 69-6 32-5 12-6 104-0 107-5 83-7 76-1 88-2 68-1 36-5 18-5 100-5 94-8 56-9 24-5 109-4 123-5 86-8 35-3 * Optimal aeration is given by aeration factor = 100Soil Conditioners Not only is a polyuronide effective in improving soil structure; cellulose esters such as cellulose acetate, methyl cellulose and carboxymethylcellulose will also improve the air-water relationships in soil (Table 1). These are substances which may be termed soil conditioners. They improve the structure of a soil by increasing the water-holding power and the soil crumb-stability. This improvement of structure enables more oxygen to become available to the cells, micro-organisms or plant roots, present in soil, at the water contents that the cells need for their meta-bolism. The increased stability of the soil crumbs diminishes soil disintegration by weathering, etc., and hence diminishes soil erosion. Soil conditioners are not plant nutrients. They yield nothing of service to the plant itself. But, by altering the soil structure, they make more oxygen and water avail-able to the plant roots.The addition of farmyard manures greatly improves the air-water relationships and crumb-stability of soil, and so does the addition of sewage sludges, composts and refuses generally in proportion to the amount of organic matter present. Extracts of soils and peats may be also very effective (see Table 1) in accordance with their content of organic matter. These observations make it clear that the com-monly occurring forms of organic matter in soils and manures greatly improve the hydrophilic properties and crumb-stability of soils. Yet the practical importance of such substances is greatly dependent on the rate at which they decompose in soil and lose their improving properties. That the addition of alginate to a soil will improve the yield of a crop, grown under glass, was shown by Quastel and Webley9 and confirmed by Owen10 and by Hedrick and Mowry11 (see Table 4) ; but it soon became certain that the fact that the polyuronide breaks down fairly rapidly in soil militates against its use on a wide scale as a soil conditioner. Again, relatively large quantities are required for the improvement of soil structure (perhaps 5-10 tons per acre) and they may cause harmful effects due to the liberation of cations which have to be added to the polyuronic acid to preserve neutrality.It was my objective to find a substance, or sub-stances, which would have the improving effects of alginate on soil structure but which would be relatively stable in soil. For use on a large scale, as a substitute for the organic matter of manures and composts, such substances would have to be, weight for weight, more effective than alginate, and without harmful effects on micro-organisms, plants or animals. The advantages of these substances for the improve-ment of fertility in soils relatively poor in, or depleted of, organic matter would be enormous. Thanks to the recent discoveries of the scientific staff of the Monsanto Chemical Company, with whose investigations in the field of soil conditioners I have been associated, such substances are now available.Synthetic Soil Conditioners Hedrick and Mowry, of the scientific staff of the Monsanto Chemical Co., using initially the mano-metric technique adopted by Quastel and Webley, and later a modification of the wet-sieving technique of Yoder12, began the screening of a large number of substances, most of which were synthesized in the Monsanto laboratories, to see if any had improving effects on soil structure. They soon found that only certain water-soluble polymeric electrolytes of high molecular weight were effective at the extremely low concentrations required by practical considerations. One of the most active substances was made by the hydrolysis of polyacrylonitrile to what is predomin-antly a sodium salt of a polyacid. Other substances that showed excellent effects were also polymers of nearly related structure. These substances had very great improving effects on soil aeration and soil aggregation11. A few typical results are shown in Table 2.Table 2. AERATION FACTORS OF SOILS TREATED WITH POLYELECTRO-LYTES (Hedrick and Mowry, ref. 11) Chemical added to standard soil (sandy loam)Concentration (percentage) Aeration factors25% 37-5% 50% 62-5% water water water waterStandard soil alone Sodium alginate Sodium alginate Pectin Lignin CRD-18Q CRD-im CRD-189 1-0 0-1 1-0 1-0 1-0 0-1 0-183 55 small small 108 106 73 26 118 85 28 small 86 77 small small 90 67 small small 130 99 63 30 128 92 66 * 40 113 99 72 35 The two materials on which most work was carried out were C-RD-189, the sodium salt of a hydro-lysed polyacrylonitrile, and CRD-186, another carb-oxylated polymer used as a partial calcium salt. Both these polymers are polyanions, that is, they contain recurring carboxyl groups along the carbon chain.These polymers have a very great effect upon crumb (or aggregate)-stability and upon soil aeration. A comparison of the effects of preparations of O.RD-186 and CRD-189 with those of several other substances on the aeration values of a sandy loam is shown in Table 2. CRD-186 and CRD-189 gave better aeration values at levels of 0-1 per cent in soil than any of the other materials at 1 per cent. This effect of CRD-186 occurs with a large variety of soils. The aggregate stability, as measured by wet-sieving technique, was greatly increased by applica-tion of the polymers to the soil, the quantity of large crumbs being increased with a higher rate of applica-tion of the polymers. Results of laboratory applica-tions of CRD-186 to a number of structurally deficient soils are shown in Table 3. Very pronounced im-provement in the workability of all soils treated with CRD-186 and CRD-189 took place. They became crumbly and friable at high water contents. Table 3. PARTICLES 0-25 mm. AGGREGATED INTO WATER-STABLEAGGREGATES o -25 mm. BY TREATMENT WITH C.RD-186 (Hedrick and Mowry, ref. 11)Soil Percentage aggregationUntreated 0-02%0-1% CRD-186C-RD-186 Paulding clay Sacramento clay26 8 29 2563 47 Miami silt loam7 4896 Cherokee silt loam7 3494 Pond loam1 3887 Renville loam5 1357 Barboursville sandy loam11 7886 Although the primary effect of the polyelectrolyte is on aggregate stability, the percolation-rate through a treated soil may show a hundred-fold increase over an untreated soil. The moisture equivalent of a soil is also improved, and evidence from experiments on the wilting of plants has indicated that all the increase in water held by the soil is available for plant growth. Treatment of soil with the poly-electrolyte results in a reduction of the rate of surface evaporation.Crumbs of soil treated with CRD-186 have remained stable under constant perfusion with water and air for 32 months at 76 F., indicating negligible biological breakdown of the soil conditioner in this period. The untreated crumbs broke down in a few minutes under the same conditions. An important question concerning the action of the synthetic soil conditioners was whether they affect adversely plant and animal life in the soil. The Warburg evaluation technique indicated that the polymers are not toxic to yeast or bacteria in the soil; moreover, the processes of nitrification are not disturbed. Spectroscopic analyses of kidney beans, wheat and radish plants grown in treated and control soils have indicated that nutrients and trace elements are not rendered unavailable in any way. Nor are the polymers toxic to earthworms, which have appeared in greater numbers in the more friable and well-aerated soil. Rats and chicks have been fed with relatively large doses of C.RD-186 and CRD-189 with no apparent ill effect.Table 4. EFFECT OF CjRD-189 AND ORGANIC FERTILIZERS ON GROWTH OF RADISHES IN MIAMI SILT LOAM (Hedrick and Mowry, ref. 11) TreatmentDosage (per cent) Average radish weight factorNone _1-0 CRD-1890-05 1-7CRD-189 + artificial fertilizer* 0-053-4 Sodium alginate Sodium alginate + artificial1-0 0-04fertilizer* 1-02-6 Commercial compost1-0 1-1Activated sewage sludge 1-00-6 Hotted cow manure1-0 2-3Peat 1-01-1 The effects of application of CRD-189 and of other substances to a silt loam on the growth of radishes are shown in the results of Hedrick and Mo wry, given in Table 4. It will be noted that alginate in the presence of added artificial fertilizers gives excellent growth, though alone it induces little or no growth owing to its mobilization of available nitrogen due to its breakdown in the soil. The synthetic polymer shows no such inhibitive effect. Crop YieldsAccording to Allison13 the application of CRD-186 and CRD-189 at rates of 0-025 per cent and 0-1 per cent to several saline and alkali soils from the western United States produce high water-stable aggrega-tions, with considerable increases in permeability of soils. Crop yields were favourably affected. Sweet corn was grown on treated and untreated soils ; whereas the untreated soils gave poor stands of corn owing to heavy crust formation, full stands were obtained on the treated soils. The quality of corn was excellent and yields were good despite the prevailing high temperatures during the experi-ments. Further experiments indicated that administration of CRD-186 facilitated removal of salt and exchange-able sodium after irrigation of the soils, a property of importance in soil reclamation.Martin, Taylor, Engibous and Burnett14 found also that application of the conditioners to various soils greatly improved water-stable aggregation and such related properties as porosity and permeability. Crop yields, particularly those of corn, oats and carrots, were considerably increased. Some of their results with sweet corn and beet are shown in Table 5. Table 5. EFFECT OF CRD-186 ON AGGREGATION AND SWEET CORN AND BEET YIELDS ON PAULDING CLAY(Martin, Taylor, Engibous and Burnett, ref. 14) TreatmentAggregation (particles >0-25mm.) (%) Sweet cornRed beets increase height over un-(in.) treated(%) weight increase per over un-30-ft. treated row(lb.) (%)Untreated 0-05% C.RD-186 0-15% CRD-ISQ 45 85 9412-1 21-3 76 24-4 102 6-7 7-7 15 8-7 30* Artificial fertilizer is 0 -1 per cent N.P.K. (6*10-4) Control of Soil ErosionEqual in importance to the experiments showing the effects of soil conditioners on the improvement of crop yields on various soils are those demonstrating the remarkable effects of conditioners in the control of soil erosion. Work by Weeks and Colter15 has shown that surface soil can be satisfactorily stabilized to the erosive action of rainfall by treating the surface with the soil conditioner. The permeable film produced by the conditioners not only stabilizes the soil, but also prevents run-off. The effect was much the same as that due to the application of a high rate of straw mulch. Addition of half to one pound of conditioner to 100 sq. ft. provided satisfactory protection to the soil. One set of results on the effects of artificial rainfall on experimental plots showed that erosion equal to a loss of 50 tons of soil per acre was reduced to a loss of 3 tons per acre by application of the soil conditioner. 'Krilium''Krilium' is the trade mark adopted by the Mon-santo Chemical Company for substances such as CUD-186 and CBD-189 sold as soil conditioners. The advent of these conditioners heralds a new phase in agricultural science, of equal importance perhaps with that brought about by the first application of the artificial fertilizers. The possibilities of improvement of fertility in the semi-arid wastes of many parts of the world, which have suffered through neglect of proper cultivation or lack of application of organic matter, are very obvious. But apart from the impor-tant economic consequences of the administration to suitable soils of the synthetic soil conditioners, it is clear that these substances afford most valuable material for further studies of the relationship between organic matter and soil fertility.

ISSN:0028-0836    

DOI:10.1038/171007a0

出版商:Nature Publishing Group    

年代:1953

数据来源: Nature

摘要:

WHILE science, in the modern sense, is often taken to date from about 1600, a year marked, for example, by the publication of Gilbert's "De Magnete", its roots are to be found far back in earlier ages. No one would deny the right of the Greeks to have some mention in a history of science, and few would omit the name of Plato, who is said to have died in 347 B.C., 2,300 years ago. Many biologists, and geologists, too, have heard of Anaximander, who died two hundred years before Plato, in 547 B.C. To include, in this annual review, the names of men who flourished before the Christian era certainly requires a rather optimistic reliance on the accuracy of historical chronology. Our justification must be that, if absolute accuracy be demanded, it might become necessary to omit the names not only of such men, but also of natural philosophers who lived many centuries later-. With this apology, we return to Anaximander (c. Gil-547 B.C.), a citizen of Miletus, arid pupil and friend of Thales,\who was not only interested in astronomy and geography, but also believed that the first animals were generated from moisture, being thus the first teacher of the doctrine of abiogenesis. He also taught that the ancestors of men were of aquatic origin. Plato (428-347 B.C.) must be regarded with mixed feelings. His attitude towards physical science, which he thought should be discussed as idealized by the mind rather than as presented by the senses, was called by Sir James Jeans a major disaster for physics.Others admire him for the immense stimulus he gave to the development of mathematics. He insisted on the value of mathematics in the development of logical thought, and over the entrance of his Academy was inscribed, "Let no one enter who is unacquainted with geometry". Although his interest in astronomy redeemed it from the reproach of atheism and thus made it respectable, his opinion that the perfection of the universe required planetary motion to be circular dominated astronomical thought for centuries, until the time of Kepler. Passing over the Dark Ages, now being illuminated by the questing beams of historians, we come to the thirteenth century A.D., when the founding of a school of science in Oxford can be attributed to Robert Grosseteste, who was born at Stradbroke, Suffolk, about 1173, and died in 1253. Grosseteste studied at Oxford, and later lectured there, ultimately becoming chancellor of the University. About 1224 he was ap-pointed rector of the school established by the Francis-cans. Here one of his pupils was Roger Bacon, who said of his master, "One man alone, our Lord Robert, knew the sciences", and it was probably due to the early influence of Grosseteste that Bacon plunged so deeply into scientific studies. Grosseteste himself was one of the earliest of the experimental scientists, and was particularly interested in optics, which he con-sidered to be the basic science. His writings include a discussion of vision, a treatise on the rainbow, and another on comets. He was made Bishop of Lincoln in 1235, an appointment which he held until his death on October 9, 1253.Coming to more modern times, three men who died in 1553 must be mentioned here. They are Reinhold, the mathematician and astronomer, Fracastoro, the physician, and Servetus, who earned a niche in medical history for his remarks on the minor or pulmonary circulation. Erasmus Reinhold (1511-53) became professor of mathematics at Wittenberg, a university founded in. 1502 and closely linked with Luther and the early days of the Reformation. Reinhold, a friend and colleague of Rheticus, who was the first disciple and staunch supporter of Copernicus, applied himself to re_-calculating to a greater degree of accuracy the tables given by Copernicus in his "De Revolutionibus", and these were published in 1551 as the "Prutenicae Tabulae" (so called in honour of Albert, Duke of Prussia, Reinhold's patron). These tables were well received at their first appearance, and were only supplanted by the "Tabulae Rudolphinae" of Kepler, published in 1627. Reinhold died on February 19, 1553, at Saalfeld, his birthplace, where he had fled in a vain attempt to escape the plague. A text-book on surveying, including mine surveying, which he had written, was published posthumously at Saalfeld in 1574. This was in use as a standard work in Germany for very many years (see Nature, 67, 42 ; 1902). Girolamo Fracastoro (1483-1553) was a Veronese physician who studied at Padua for some years. The fact that Copernicus was a fellow student adds inter-est to his astronomical work, "Homocentrica". This is an elaborate and somewhat obscure attempt to offer a new planetary system. In it he made the important observation that comets' tails are always turned away from the sun. When, in 1517, certain excavations revealed fossil shells, Fracastoro's comment that they must be remains of once living creatures earned him a place in the history of geology. His fame, however, rests on two medical books. In one, a poem, "Syphilis sive Morbus Gallicus", he described the disease which came to be known by the title of the poem ; and, in his later and more important work, "De Contagione", he classified for the first time modes of infection and gave detailed descriptions of a number of fevers, including typhus.A younger contemporary of Fracastoro was the unfortunate Spaniard, Miguel Servet y Reves (1509-53), better known as Michael Servetus, who was burnt to death at the stake, at Geneva, by Calvinists for the heretical opinions expressed in his "Christianismi Restitutio", a copy of which was tied to his waist. It was in this book that Servetus described the passage of the blood through the lungs. His account could have attracted little attention at the time, for, of the edition of about a thousand copies, half were burnt with an effigy of Servetus by the Catholic Inquisitor at Vienne on June 17, 1553, and the other half, which had been sent to Frankfurt, were destroyed at the request of Calvin some months after Servetus's death on October 27. It was well over a century before anyone directed attention to his contribution to physiology. Two naturalists born in 1553 were Thomas Moufet and Prospero Alpino. Moufet (1553-1604), the son of a Scottish haberdasher, was born in London and educated at Cambridge. He studied medicine and later became a fashionable physician. He is remem-bered for the "Theatrum Insectorum", the first British work devoted to insects, which, however, did not appear until thirty years after his death. It was based on the work of Thomas Penny; but the manuscript, which survives in the British Museum, has many excellent drawings by Moufet. Alpino, another physician, born at Marostica in the Republic of Venice on November 23, 1553, studied at Padua and took his doctor's degree there in 1578. He spent three years in Egypt, and afterwards published several works on the natural history of that country, the best known being his "De Plantis Aegypti Liber" (1592). He enriched the botanical garden at Padua with Egyptian plants.No outstanding scientist seems to have died in 1653, but two men born in that year have some claim to fame. J. Conrad Peyer, a Swiss zoologist, has his name commemorated in Peyer's patches, the intestinal glands which he figured in 1677, though he was not the first to describe them. He was also the author of a monograph on the compound stomach of ruminants. Peyer died at Basle in 1712. To have been deaf and dumb until the age of seven, and even after that age always to lack a normal voice and ear, would seem handicap enough in life without inviting further embarrassment by taking up the study of the physics of sound. Yet that was the choice of Joseph Sauveur, born at La Fleche on March 24, 1653. He was a student of the popular Rohault, and was elected to the Royal Academy of Sciences, Paris, in 1696. Although he has been described as the founder of acoustics, it has recently been shown (Lloyd, LI. S., Notes and Records Roy. Soc., 3, 149 ; 1941) that much of his work on harmonics had been anticipated by contributors to the Philosophical Transactions. He died in 1716. Before noting bicentenaries, one cannot pass without remark the fact that in 1703, two hundred and fifty years ago, occurred the death of the famous Robert Hooke and the almost equally celebrated mathematician John Wallis.The year 1753 is an epic one in the annals of natural history in Britain, for it was in the course of that year that Parliament passed "An Act for the Purchase of the Museum or Collection of Sir Hans Sloane and of the Harleian Collection of Manuscripts, and for providing one General Repository for the better reception and more convenient use of the said Collections", that is, virtually, for the foundation of the British Museum. Sloane had died on January 11, 1753, in his ninety-second year, and it was his wish that his enormous collections, which included 40,000 books, as well as manuscripts, coins, and botanical, zoological and mineralogical specimens from all over the world, should pass to the nation. He therefore instructed his trustees to offer them to the King or to Parliament for the sum of 20,000, which he believed to be less than a quarter of their true worth. If the offer was refused then other countries were to be approached, and he named the Royal Academies of Sciences at St. Petersburg, Paris, Berlin and Madrid, in that order. George II showed little interest in the offer when approached by Sloane's trustees, remarking, with good reason, that there was not 20,000 in the Treasury. Parliament, however, urged on by Speaker Onslow, passed the Act referred to above. To raise the necessary sum it was agreed to hold a national lottery, which was intended to produce 100,000. Although the lottery was suc-cessful in the latter aim, the traffic in tickets by the jobbers and gamblers who handled the business became a public scandal. Sloane, the son of a Scot, was born in Ulster in 1660. As a student of botany and medicine in London he became friendly with John Ray and Robert Boyle. He continued his studies in France, and returned to London in 1684 with many rare plants and seeds. In 1687 he went as physician with the Duke of Albemarle to the West Indies. Here, during a stay of some fifteen months, he made an extensive collection of plants, animals and minerals. His collections grew steadily as the years passed, and he purchased or acquired by bequest those of other collectors. Sloane was elected a Fellow of the Royal Society in 1685, and became secretary in 1693. In many ways he did good work for the Society, and in 1727 he succeeded Sir Isaac Newton as president, only resigning fourteen years later, when he felt his advancing years no longer permitted him to discharge his duties satisfactorily. He then retired to his country house in Chelsea, where his museum and belongings were removed, and where he died. His statue by Rysbrack still stands in the Chelsea Physic Garden, and the monu-ment over his grave in Chelsea churchyard has been more fortunate than the church in escaping war damage.Three days after Sloane, on January 14, 1753, another famous Fellow of the Royal Society died. This was Bishop Berkeley (1685-1753), the philo-sopher, who, like Sloane, was born in Ireland. Berkeley's philosophical works are well known, as well as his controversy with the mathematicians over the method of fluxions. A different aspect of his character is revealed by his cherished scheme to found a college in the Bermudas, where the English youth of the Plantations could study side by side with "the young American savages". Berkeley was actually successful in persuading Parliament to vote him 20,000 to promote his proposals; but, although he immediately crossed the Atlantic with his wife, and then spent three years in Rhode Island awaiting funds, he eventually despaired of receiving the money and returned to England in 1731. He died quite suddenly a few months after settling in Oxford, and was buried there in Christ Church. Three other scientists who died in 1753 call for brief mention. Nicholas Fatio de Duillier (1664-1753) was a Swiss mathematician who spent much of his life in England, and was elected a Fellow of the Royal Society in 1688. He was prominent in the Newton-Leibniz controversy, being the first to accuse Leibniz of plagiarism. He demonstrated to the Royal Society the use of jewelled bearings for watches, and also wrote on navigation. Becoming involved with a group of religious fanatics, in 1707 he appeared in the pillory at Charing Cross for publishing prophecies likely "to terrify the Queen's people". After some years abroad he retired to Worcestershire, where he died on April 24 in his ninetieth year.Georg Wilhelm Richmann, one of science's martyrs, was born at Pernau in 1711, and became professor of experimental philosophy at St. Petersburg in 1745. He deduced a formula for calculating the tempera-ture of mixtures, which was used by Wilcke in his experiments on the melting of snow. Richmann met his end in an unusual way. An enthusiastic student of electric phenomena, he was killed in the summer of 1753 during a thunderstorm by a flash of lightning which passed through his body from a lightning, collector with which he was experimenting. The strange manner of his death was made known in two communications to the Philosophical Trans-actions. Thomas Melvill (1726-53), a Scot, was only twenty-six when in 1752 he communicated a paper to the Edinburgh Philosophical Society in which he de-scribed the examination through a prism of flames into which different salts had been introduced. These experiments establish him as one of the pioneers of spectrum analysis. He died in December of the following year at Geneva.The stars of 1753 seem to have shone favourably for the birth of inventors, for six men born in that year whom we notice all had a strong bent towards practical science. The best known of them is Sir Benjamin Thompson, Count Rumford, who led a varied and colourful life. Born in Massachusetts on March 26, 1753, he arrived in England in 1776, his Royalist sympathies having made it advisable for him to leave America. In the War of Independence he served as an officer in the British Army, but at the end of the war, in 1783, he returned to England again. Soon afterwards he set out to visit Europe. In 1784 he entered the service of the Elector of Bavaria, and, becoming his principal adviser, he carried out many social reforms. It was during this period that he made in Munich his famous experi-ments on heat. He had been knighted by George III in 1784, and seven years later was created a Count of the Holy Roman Empire, when he chose to com-memorate in his title the Massachusetts township (now Concord) with which he had close associations. Returning to London in 1798, he applied himself enthusiastically to drawing up proposals for founding a public institution "for diffusing the knowledge and facilitating the general introduction of useful mech-anical inventions and improvements". These pro-posals led to the founding of the Royal Institution, in 1799. In his house in Brompton Row (a little east of Brompton Oratory, in what is now Brompton Road) he installed the many improvements in heating to which he had devoted so much of his time. The house was freely exhibited to visitors from all classes of society, and for several years attracted curious sightseers. Its furniture included beds disguised by day as elegant sofas, built-in cupboards, and hinged panels which could be raised to form writing-tables near the fire or window. Rumford spent his last years in France, where he died at Auteuil at the age of sixty-one. Another somewhat unusual character born in 1753 was Charles, third Earl Stanhope. Elected a Fellow of the Royal Society at the age of nineteen, he devoted much of his income to experiments in natural phil-osophy. He made two calculating machines, now in the Science Museum at South Kensington, and con-structed the first iron printing press. The latter, together with his invention of stereotyping by a plaster process, he presented to the Clarendon Press in 1805, and they were in use for some years. Stanhope died in 1816. A man in a very different walk of life to the noble earl was Samuel Crompton (1753-1827), inventor of the spinning mule which did so much to raise the status of the cotton industry. Other con-temporaries were Edward Troughton (1753-1835), the renowned maker of astronomical instruments, who received the Copley Medal of the Royal Society in 1809, and William Nicholson (1753-1815), who with Sir Anthony Carlisle was the first to con-struct a voltaic pile in Britain, and with it observed the electrolytic decomposition of water. He was also the founder and editor of Nicholsori's Journal, one of the first of the independent scientific journals in Britain. We must also mention F. K. Achard (1753-1821), the German chemist who discovered a com-mercial method of extracting sugar from the sugar-beet, so laying the foundation of an industry which rapidly became of considerable economic importance. In 1853, geological science suffered two losses in the deaths of C. L. von Buch (born 1774) and H. E. Strickland (born 1811). Von Buch had been a pupil of Werner at Freiberg and an intimate friend of Humboldt. He made many valuable contributions to geology, in particular a description of the Canary Islands, which he visited in 1815. He also made important observations on the change of sea-level along the Swedish coast, compiled the first geological map of Germany, and made notable contributions to palaeontology. Von Buch reached, the ripe age of seventy-nine ; but Strickland was only forty-two when he was killed by a train while making geological observations in a railway cutting near Retford. He was the author of a number of geological and ornithological papers, and in 1850 was appointed deputy reader in geology at Oxford, during the illness of Buckland. Strickland was one of the founders of the Ray Society, and edited for the Society the "Bibliographia Zoologies et Geologiae" based on the manuscripts of Agassiz, though on account of his untimely death the fourth volume was completed by his father-in-law, Sir William Jardine. Strickland was also joint author of a classic memoir on the dodo.French scientists lost several of their number during 1853, the best known being Dominique Frangois Jean Arago, physicist and astronomer, born near Perpignan in 1786. At the age of eighteen he became secretary to the Observatory in Paris, and two years later * accompanied Jean Baptiste Biot to Spain in order to assist him in completing the meridional measurements begun by Delambre. After Biot had returned to Paris, Arago became involved in the most fantastic adventures, which included imprisonment in a fortress, escape in a fishing boat, and capture by a Spanish corsair. Eventually he arrived back in Paris, still in possession of the records of his survey, which he had preserved through all his vicissitudes. Soon after his return he was elected to the Academy of Sciences at the remarkably early age of twenty-three, and about the same time Napoleon appointed him as one of the astronomers of the Royal Observatory. Arago carried out notable researches on the polarization of light. He also discovered the "magnetism of rota-tion", which was not interpreted until Faraday discovered electro-magnetic induction. Arago received the Copley Medal of the Royal Society in 1825 and died on October 2, 1853. His compatriot, Auguste Laurent (1808-53), a brilliant young chemist who died a few months before, on April 15, had led a very different life from that of the accomplished and successful Arago. Always struggling against poverty, and apparently ostracized by his French colleagues, some of his experimental work was carried out in a damp cellar white he worked as assayer to the Mint. He is credited with a number of discoveries in the field of organic chemistry. He died of consumption, and his famous *'Method e de Chimie" was published posthumously. Another organic chemist, Leopold Gmelin (1788-1853), perhaps the best known of a distinguished German scientific family, died two days before the unfortunate Laurent. He was professor at Heidelberg, and the author of the great "Hand-buch der Chemie", translated into English (1848-72) for the Cavendish Society by Henry Watts. Other deaths in the same year were those of C. J. Doppler (born 1803), the Austrian physicist who discovered the principle named after him, K. J. B. Karsten (born 1782), the German mineralogist, and M. J. B. Orfila (born 1787), the celebrated toxico-logist. In America the deaths were reported of Sears Cook Walker (born 1805), astronomer, and William Beaumont (born 1785), physiologist. The latter, an American surgeon, for many years made observa-tions on the stomach of a French-Canadian trapper who had suffered a severe gunshot wound. The per-sistent opening in the wall of his stomach permitted Beaumont to make experiments which threw con-siderable light on the nature and flow of the gastric juice.A number of particularly distinguished men were born in 1853, including four who received Nobel Prizes. Wilhelm Ostwald, born at Riga on September 2, held a professorship of chemistry at the Baltic Polytechnical School of Riga during 1883-87, and then became professor of physical chemistry at Leipzig. When he retired in 1905, at his own request, in order to devote himself to research, h,e was nomin-ated by the Emperor of Germany as the first exchange professor with the United States. In 1909 he received the Nobel Prize for chemistry. His contributions to physical chemistry were numerous, and too well known to need detailing here; but it is worth recalling that in the industrial field he developed the process for producing nitric acid by the catalytic oxidation of ammonia, which became the main source of Germany's supply of nitric acid during the First World War. Ostwald died on April 4, 1932. A contemporary of Ostwald's, who worked with him for a time at Leipzig, was Ernst Beckmann (1853-1923), who became director of the laboratory for applied chemistry there in 1897, a position he held until 1912. The Beckmann thermometer and Beckmann freezing-point apparatus for the determ-ination of molecular weights are well known.An outstanding figure of the period under review was the Dutch physicist, Hendrik Antoon Lorentz, born at Arnheim on July 18, 1853. At the age of twenty-five he was appointed professor of theoretical physics at Leyden, and occupied the chair there with great distinction for forty-five years. The Lorentz transformation, made known in 1903, became the basis of the theory of special relativity. With Zeeman, he was awarded the Nobel Prize for physics in 1902. He was a Foreign Member of the Royal Society, and received the Rumford Medal in 1908 and the Copley Medal in 1918. He died at Haarlem on February 4, 1928. Another eminent Dutchman, only a few months younger than Lorentz, was the genial Heike Kamer-lingh Onnes (1853-1926). Born at Groningen, he passed several years at Heidelberg under Bunsen and Kirchhoff. Appointed professor of experimental physics in Leyden in 1882, he founded the famous Cryogenic Laboratory, where he achieved his great triumph, the liquefaction of helium, in 1908. Like Lorentz, he was awarded a Nobel Prize for physics (1913), and was a Foreign Member of the Royal Society. A fellow student of Onnes at Heidelberg in 1872 was W. F. Hillebrand (1853-1925), the American geochemist, who after joining the U.S. Geological Survey in 1880 became specially distinguished for his analyses of rocks and minerals. He made many analyses of the mineral uraninite between 1882 and 1892, and was puzzled by the presence in it of an inert gas, afterwards identified by Ramsay in 1895 as helium. Later, his highly skilled analyses of radio-active minerals were used in determinations of the age of the earth by Holmes and others. A distinguished Italian mathematician, M. M. G. Ricci (1853-1925), who developed the tensor calculus, also comes into this period.In the biological sciences two men must be mentioned. Albrecht Kossel (1853-1927), trained as a physiologist, devoted his researches to chemical subjects and became one of the leaders in the then new science of biochemistry. He was professor of physiology at Heidelberg during 1901-23, and did notable work as director of the Institute for Protein In-vestigation. He was awarded the Nobel Prize for Medi-cine in 1910, and died at Heidelberg on July 6, 1927. No admirer of the work of Pasteur will have forgotten his devoted young assistant Emile Roux (1853-1933), who was so closely connected with the renowned researches on anthrax and rabies. With Alexandre Yersin he discovered the diphtheria toxin, an achievement leading to the discovery of the anti-toxin by Emil von Behring in 1890. In 1904, Roux succeeded Duclaux as director of the Institut Pasteur in Paris. He died just before his eightieth birthday, on November 3, 1933, and received a national funeral. Roux had been elected a Foreign Member of the Royal Society in 1913, and received the Copley Medal in 1917.In conclusion, it seems worth reminding readers that at the anniversary meeting of the Royal Society in November 1853, the president, the Earl of Rosse, informed the Society of a memorial made to the Government bearing some two hundred signatures, including those of many Fellows of the Society, requesting a building for the housing of scientific societies in the metropolis. As a result of this petition, Burlington House was eventually made available to the Royal and other societies, after a site at South Kensington had been refused by men of science on account of its inconvenience.

ISSN:0028-0836    

DOI:10.1038/171010a0

出版商:Nature Publishing Group    

年代:1953

数据来源: Nature

摘要:

DURING the International Polar Year of 1932-33, Appleton and Ingram1 established a correlation between magnetic storms and temporary reductions of -FVregion electron densities at high latitudes.. At moderately high latitudes, too (Slough, England), they found that J^-region perturbations were associated with magnetic storms ; but here the perturbation was sometimes an increase followed by a decrease of -FVmaximum electron density. At equatorial latitudes Berkner and Seaton2 showed that the normal tendency was for .FVelectron densities to increase during magnetic disturbance. On the basis of these facts, Appleton and Piggott3 have proposed a system of classification of iono-spheric storms which bears a superficial resemblance to that adopted by Birkeland for magnetic storms (for example, 'negative polar storm', 'positive equatorial storm'). On this method of classification certain anomalies appear ; for example3, "Washing-ton (lat. 38-5 1ST.; long. 77 W.) mostly behaves like an auroral-zone type of station, whereas Burg-head (lat. 58 N. ; long. 3 W.) and Leningrad (lat. 60 N. ; long. 30 E.) are predominantly non-auroral type medium-latitude stations, although all three lie on the same magnetic latitude".This tentative classification of Appleton and Piggott's is based on the study of noon values of ./^-electron densities. Martyn4 has already pointed out that there is a pronounced diurnal (local time) variation in Fz -region parameters during magnetic disturbance. This is found to be big enough to produce inconsistencies if Appleton and Piggott's mode of classification be followed. For example, if midnight instead of noon values be taken, auroral observatories show an increase of FZ -electron densities. A satisfactory method of classification of iono-spheric storms almost necessarily presupposes the existence of a plausible theory of their occurrence. Until 1950 it was generally supposed that such storms were due to local impact of particles from the sun, which in high latitudes heated the ionosphere, so reducing electron densities, and in low latitudes contributed to the ionization in some unexplained way. In that year Martyn5 put forward the hypo-thesis that disturbances of the F2-Tegion associated with magnetic activity were due in all cases (save possibly 'great' magnetic storms) not to direct particle bombardment, but to the effect of an electro-static field which spreads over the earth from the intense current systems set up in the auroral zones during all magnetic storms. This field, if it has the magnitude and phase necessary to produce the solar diurnal (Sp) current system in the ionosphere, will, it is found, produce the observed perturbations of the ^2-region by causing electron (and ion) drifts in accordance with concepts previously advanced6 to explain tidal phenomena in the ionosphere.Using this theory as a preliminary hypothesis, an extensive study has been made, during the past three years, of the geo-morphology of -F2-ionospheric perturbations associated with magnetic storminess On this basis it was logical to examine both Sp (/V2 and h'Fa) and Dst (/V* and h'Fz) using the methods and terminology developed by Chapman for the corre-sponding magnetic variations ; namely, in the case of the ionospheric DKt (disturbance, storm-time), to measure time from the beginning of the sudden or gradual commencement of the corresponding magnetic storm. Using this procedure the following conclusions have been reached : All major perturbations of the F2-region, save those associated with the relatively small travelling disturbances7 of unknown origin, are associated with magnetic storms. There is no evidence that such storms travel from the polar zones, with travel-times of the order of hours or days, as has been suggested from time to time. The ionospheric storm at all latitudes begins, either simultaneously with, or in a time less than one hour after, the com-mencement of the corresponding world-wide magnetic storm. The effect of a magnetic storm on the F2-TGgiou depends markedly on the season. In summer, the general tendency of a storm is to lower electron densities, and to raise the heights at which the maximum densities occur. In winter the densities are reduced in the morning hours, and raised in the afternoon hours.Fig. 1. S])(h'Fi) average diurnal variation of h'p^ (minimum equivalent height of JFVregion) for five International magnetically disturbed days each month minus same variation for five International quiet days each month, for :(1) Fan-banks, magnetic latitude (O) *= 64-7 K., April 1944-Dec. 1948. (2) Washington (O = 50-3 N.), Jan. 1941-June 1948.(3) Canberra (O = 44-0 S.), March 1937-June 1948. (4) Watheroo (X = 41-7 S.), Jan. 1944-Dec. 1948.(5) Kihei (X = 20-9 N.), March 1946-Dec. 1948. (6) Huancayo D = 0 -6 S.), Jan. 1942-Oct. 1948. The scale unit is 10 km. in each case.Fig. 2. Sj)(S Ft) average diurnal variation of f p.2 (critical pene-tration frequency of JVregion) derived as for h'pt in Fig. ] for :(1) Fairbanks (see Fig. 1). (2) Burghead E = 60-7 N.), Jan. 1943-Dec. 1946.(3) Washington (see Fig. 1). (4) Canberra (see Fig. 1).(5) Watheroo (see Fig. 1). (6) Kihei (see Fig. 1).(7) Huancayo (see Fig. 1). The scale unit is 0 -2 megacycle per second in each case.There is a general tendency for electron densities to be lowered on the average at high latitudes and raised at low latitudes. However, as mentioned above, this state-ment has to be taken in conjunction with the local time at which such densities are studied. For example, at local midnight, electron densities are above average at high lati-tudes and below the average in tropical latitudes not too near the magnetic equator (for example, Hawaii, Fig. 2). The SD (local time) variation is large and predominantly diurnal (Figs. 1 and 2). Densities are lowest in the mornings and highest in the evenings. The phase of the diurnal variation advances by about four hours as one passes from auroral to equatorial latitudes.At Fairbanks (Alaska) minimum densities (and greatest heights) occur at 11 hr. local time; in equatorial zones at about 07 hr. There is no evidence that any magnetic storm affects the northern and southern hemispheres differently, when due allowance is made for the seasonal effect described above. The initial effect of any magnetic storm on the Fz-region depends markedly on the local time of commencement. If the storm commences at a time when the local $D(/V2) curve is at its highest point (say 22 hr. at temperate latitudes), the initial disturbance is a decrease of /Va (that is, the variation initially follows the /Sj>(/Vj) curve). If, on the other hand, the storm commences at, say, 10 hr., the initial effect is an increase in /V2- It is suggested that the anomalous result found by Appleton and Piggott3 for Washing-ton is due to the inclusion of a preponderance of storms commencing in the (local) evening hours in their data. When allowance is made for this bias, Washington is found to have the appropriate char-acteristics of a temperate-latitude station. This effect is shown for Watheroo in Fig. 3, which exhibits the departure of fQpt from normal during the first three days of magnetic storms which commenced between (A) 08 and 11 hr. local time, and (B) 20 and 23 hr. local time. (In group A are included IT storms, in B 11 storms.) It will be seen that on. Appleton and Piggott's classification Watheroo would be classified as a temperate-latitude station on the basis of group A storms, andas an auroral station on the basis of group B storms. It appears that -F2-region ionospheric storms, like magnetic storms, have a unitary character, and may be regarded as manifestations of a single world-wide phenomenon. The local effects produced by this single phenomenon, which it is suggested is the electrostatic field of the SD current system, depend markedly on local time and season.The theoretical (Chapman) diurnal, seasonal and latitude characteristics of the -F2-region are normally perturbed by solar tidal electric fields, along lines previously reported8. It appears that the phase of the additional electric field present during magnetic storms is such as to increase these perturbations at high latitudes, and to reduce them at low latitudes. This is specially obvious at Huancayo, where the normal daily departures of the ^-region from 'Chapman' behaviour are large, leading to noon minima of ionization density, and abnormally rapid pre-dawn reduction of these densities. During mag-netic storms these anomalies are removed, and the diurnal variation of F^-region electron densities in the vicinity of the magnetic equator approximates more closely to that anticipated for a simple 'Chapman' region. Fig. 3. Dtf(/V,) at Watheroo. Hourly values of f pl for first three days of magnetic storms minus corresponding hourly values for magnetically quiet days, for (A) storms com-mencing between 08 and 11 hr. local time : and (B) storms commencing between 20 and 23 hr. local timeThis work is published by permission of the Radio Research Board of the Commonwealth Scientific and Industrial Research Organization. I am indebted greatly to Miss B. Hardwick, who has supervised the reduction into appropriate form of ionospheric data from co-operating observatories. * Substance of papers presented at the recent meetings of the International Scientific Radio Union and of the Mixed Commission on the Ionosphere, at Sydney and Canberra, Australia.

ISSN:0028-0836    

DOI:10.1038/171014a0

出版商:Nature Publishing Group    

年代:1953

数据来源: Nature

摘要:

JOHN HENDERSON SMITH, who died on November 28, graduated from Baliol College, Oxford, in 1898, proceeded to Edinburgh, where he took his medical degree in 1903, and then returned to Oxford as Philip Walker Student in pathology. Later, he was appointed bacteriologist to the Lister Institute. Here he did some promising work on immunology ; in one of his early investigations, published in 1907, he demon-strated that the concentration of anti-toxin in the blood at any time depends on the route of intro-duction. Later, in conjunction with Brooks, he studied the influence of the dose of antigen on the output of the antibody and on its time of appearance ; the results were published in 1912. All this work was characterized by cleanness and accuracy of experi-mental technique, and by careful and critical examination of the results ; he seemed to have the prospect of a very promising career in his subject. Then, unfortunately, he was struck down with tuberculosis, and although he made gallant attempts to continue his work he had to give it up ; in 1916 he left the Institute.Henderson Smith refused, however, to abandon scientific work. Fortunately the Rothamsted Experimental Station was beginning to expand and had brought plant diseases within its ambit. Its policy was to bring in, young people each well trained in some pure science which he or she could apply to the problems of the Station ; in connexion with the new developments, it was desired to find someone well grounded in human or animal pathology who could introduce new ideas and methods into the study of plant pathology. Henderson Smith was attracted to the work ; by 1919 he had recovered sufficiently to join the staff, and the healthy sur-roundings and the devoted care and attention of his wife enabled him to stay out his full term of service with no further serious trouble. He retired on reaching the age limit in 1940. Henderson Smith's first investigations at Rotham-sted were on the growth-rate of fungal hyphae, but he soon turned to more fundamental studies of the killing of fungus spores by phenol; these proved to be a valuable contribution to the general theory of disinfection. Plant virus diseases were then coming into prominence and he turned over to them : his work soon attracted attention, and following a request from the Imperial Mycological Conference of 1929 that virus diseases should be more fully studied, the Empire Marketing Board provided funds for a research team under his leadership. The work included the nature of the cell inclusions the so-called X-bodies the concomitant bacteria in virus diseases, and the size of the viruses.When W. B. Brierley left Rothamsted in 1932 to occupy the chair of agricultural botany in the University of Reading, Henderson Smith was appointed to succeed him as head of the Department of Mycology ; it continued to expand and to attract able young people, becoming one of the most vigorous at Rothamsted. He served as president of the Association of Applied Biologists, and was also president of the Virus Section of the 1939 International Congress of Microbiology. 'H. S.', as he was always affectionately called, enjoyed much quiet esteem among his colleagues. Under his wife's watchful care he had to be cautious in all matters pertaining to health, but this did not restrict his interests. Like his wife, he was well read ; in addition, he was a recognized authority on book plates, of which he was a discriminating collector, and an ardent and competent player of golf and of bridge. He never sought popularity, but his courage and his persistent determination to go on with his work in spite of threatened ill-health won him much respect from those who knew him well.

ISSN:0028-0836    

DOI:10.1038/171016b0

出版商:Nature Publishing Group    

年代:1953

数据来源: Nature

摘要:

FRANZ NAGELSCHMIDT, a pioneer of physical medicine, died on October 4 in Manchester. He was born in Berlin on January 29, 1875. He studied medicine, but soon became also interested in physics, for he thought that the many advances in modern experimental physics taking place at the end of the past century could be utilized for medical purposes. He went first to Copenhagen to work with Finsen, the founder of light therapy. He then returned to Berlin and established a light treatment institute at the Charite, where he installed the first X-ray unit for therapeutic purposes in 1903. In 1904, be founded a light treatment institute in Breslau, where he applied radium rays for the first time for treatment. In 1906, he settled in Berlin and founded the Finsen Clinic, of which he was in charge until 1933. Here he developed diathermy the name was coined by him, and generally adopted, for the creation of heat inside the tissue by external application of electric currents, his best-known discovery. He also designed and introduced an ultra-violet lamp without water cooling. This lamp, the prototype of modern ultra-violet lamps, carried his name for several years. In 1911, he designed an apparatus to produce 'electro-rhythmic current' for electrical vibration treatment. In 1912, he invented the neon lamp, originally for medical purposes. In 1933, Dr. Nagelschmidt left Germany for Great Britain, where he was immediately made an honorary consultant of physiotherapy at the Jewish hospital in London. In 1934, he had been awarded the "Golden Key" of the American Congress of Physical Therapy for "outstanding service to the science of physical medicine". In 1936, he qualified in Edin-burgh as a medical practitioner and settled in Man-chester as honorary consultant in physiotherapy at the Jewish hospital. He also founded a private therapeutic institute where he practised physio-therapy and carried out research until about three hours before his death.Nagelschmidt was a man of many talents and many interests, in art as well as in science. In spite of all his achievements, he was a very modest man. This modesty made him call all the therapeutic establishments installed by him after his teacher Finsen, and this may explain why the scientific world knows the name of Finsen, who first conceived light therapy, much better than the name of Nagelschmidt, who developed it and who added all the other forms of physiotherapy to it. It may also account for the fact that few honours were bestowed on this great man.

ISSN:0028-0836    

DOI:10.1038/171017a0

出版商:Nature Publishing Group    

年代:1953

数据来源: Nature