摘要:

CONSIDERING the importance of wood and kits by-products in the necessities of life, it is strange how comparatively little systematic action has been taken in England to study the constitution of wood-substance and the structure and properties of the different timbers in relation to their uses. Much of our knowledge, whether it be of the chemistry of wood or its mechanical and physical behaviour, is empirical. Most of the difficulties encountered in connexion with timber are due to its extraordinary lack of uniformity. When anything goes wrong, as, for example, when an aeroplane strut breaks without warning, the first question always asked is: 'Is this a normal piece of wood ? ' A piece of wood may be regarded as normal or abnormal from several different points of view; for example, in its behaviour under mechanical stress, in either its minute or gross structure, with respect to its treatment during seasoning, or as representing normal growing conditions. The interrelation of these aspects is of very great importance. A timber is usually judged in practice by its mechanical properties, but until our knowledge of the connexion between structure, growth, seasoning, and strength is increased, it will remain impossible to assess the mechanical properties of a piece of timber with any degree of certainty otherwise than by actually breaking a test stick. Further, will the growing conditions which the forester aims at as ideal, produce timber which gives the best results under mechanical tests ?One can only hope to solve such problems by the close collaboration of a number of specialists in different branches of research. The establishment, under the Department of Scientific and Industrial Research, of the Forest Products Research Laboratory at Princes Risborough, within sixteen miles of the Imperial Forestry Institute at Oxford, has opened up a prospect of such collaboration which both institutions have been quick to grasp. These two institutions together provide the much-needed link between the sylviculturist on one hand and the wood-user on the other, harnessing science to the task of informing the sylviculturist of the species to plant, the quality of timber desired, and the means of obtaining it, and the wood-user of the right timber for the several uses, based on mechanical and physical properties, with the best method of preparing it for use. In this work the Imperial Forestry Institute is primarily concerned with the living tree, from the germination of the seed to the felling of the tree for timber: from this point the problems are proper to the Forest Products Research Laboratory, which is concerned with mechanical strength, seasoning, preservation, and manufacture of the timber, and with the investigation of by-products. There exists, however, a common ground, more especially in wood technology, mycology, and entomology. In these three subjects, in order to secure the closest co-operation, the staffs of the two institutions have been practically combined to form a joint section, working on a joint programme, the Forest Products staff being housed at the Imperial Forestry Institute at Oxford.In dealing with complex problems, it has thus been possible to co-ordinate very different aspects. and the personal contact between the two staffs greatly-facilitates the dissemination of information and ideas. For example, a number of independent lines of research, which are being undertaken, have been so arranged that their results may form the. basis of an investigation into the problem of 'brashness,' which means an unexpected brittleness in a wood which is not normally brittle; this is a problem of particular importance in aeroplane construction. Other problems coming within this system of co-operative research are the relation between anatomical variation, mechanical strength, and growing conditions; the range of variation consistent with normal mechanical strength; the physical and chemical factors involved in the process of seasoning; the effect of different degrees of fungal attack and the possible relation between insect and fungal attack. In the chemistry of wood-substance, a beginning has been made by arranging for work to be carried out under Sir James Trvine at the University of St. Andrews. This will be closely coordinated with the physicochemical research included in the joint programme of the Laboratory and the Imperial Forestry Institute, especially in its relation to shrinking and swelling. The problems connected with colonial timbers also can only be effectively solved by a combined investigation in which both the growing of the timber and its utilisation are fully considered. Here the co-operation of the systematist and the wood technologist forms an indispensable link, and is very strong under the existing arrangements. Such a combined scheme has already been put forward, in a joint pamphlet which has been circulated to the Forest Services of those parts of the British Empire which do not yet possess facilities to undertake the work themselves.

ISSN:0028-0836    

DOI:10.1038/119881a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

ANY anthropologist into whose hands this book may come will rub his eyes to find himself translated to an atmosphere of theological controversy which might well be that of the seventeenth century. Indeed, he may even go further and ask why a series entitled " L'Evolution de l'Humanit6," or, in translation, " A History of Civilisation," in which an impersonally objective treatment of its subject matter might reasonably be expected, should include a book so subjective in outlook as Dr. Summers' " History of Witchcraft and Demonology." It is surely not the function of the student of the development of thought and belief to inquire into the truth or validity of the tenets he examines, or to obtrude his own beliefs; his interest lies in the process of development and its product; he may legitimately be expected to regard them as objective matters of fact, the truth or falsity of their content being irrelevant to his purpose. Dr. Summers, however, believes in witches, and accepts the witchcraft belief as set forth in contemporary or nearly contemporary accounts and in the reports of witch trials as in the main a true record of a real cult and an actual manifestation of the principle of evil. He believes in the possible efficacy of a malediction. It is true that he acknowledges that the leader of the witches' coven was often proved to be a man-Francis Bothwell, for example, for political and other reasons was suspected of inspiring the Berwick witches who were accused of plotting against James I., and the suspicion is made almost a certainty by his notorious reputation as a 'witch master' when afterwards living at Naples-but he says:"When God's Ape the Demon can work so successfully and obtain not merely devoted adherents but fervent worshippers by human agency, there is plainly no need for him to manifest himself in person either to particular individuals or at the Sabbats, but none the less that he can do so, and has done so, is certain, since such is the sense of the Church, and there are many striking cases in the records and trials which are to be explained in no other way." It is therefore with scarcely a feeling of surprise that we read: " anthropology alone offers no explanation of witchcraft. Only the trained theologian can adequately treat the subject." In the true spirit of the orthodox when a belief in witchcraft was a test of orthodoxy, Dr. Summers gives a long list of fathers of the early Church, theologians, lawyers, and writers on witchcraft who held firmly to the belief in the reality of the existence and powers of the witch; but he might just as well have cited an almost equally long list of those who denied it. It is significant that while references to Sprenger and the " Malleus Maleficarum "-the bible of the witchfinder-Boguet, Bodin, and de Spina are frequent, such writers as Scott, Cotta, Bernard, Wierus, Webster, Becker, and Hutchinson, critics of the belief, are barely mentioned, if at all. As most of these writers are English, it may be that Dr. Summers will deal faithfully with them in the later volume in which he promises to discuss the witchcraft belief in its local manifestation in England, France, Germany, and elsewhere.Bodin, the famous French lawyer and writer of the sixteenth century, defined a witch as " Sorcier est celuy qui par moyens diaboliques sciemment s'efforce de parvenir a quelque chose " (a sorcerer is one who by commerce with the devil has a full intention of attaining some end). British jurists laid rather more stress on the existence of a pact with the devil. Virtually there was a general agreement in the witchcraft prosecutions in the fifteenth, sixteenth, and seventeenth centuries throughout Europe and in the American colonies, that whatever may have been the specific act upon which the accusation was brought, witchcraft involved a league with the devil and a renunciation of Christianity. The frenzied fear of the populace was responsible for the cruelty of the duckings and other forms of outrage and the witchfindings of Hopkins and his peers in the small towns and villages of Puritan England and Presbyterian Scotland of the seventeenth century, but it was the animus of the Church against the heretic which brought literally thousands to their death after the issue of the Bull of Innocent VIII. in 1484. It is quite correct, as Dr. Summers points out, that the witchcraft prosecutions did not begin with this Bull; but they increased enormously in number after its promulgation, and it was responsible for the activities of Sprenger and his colleagues in Germany, inspiring them to the authorship of the " Malleus Maleficarum," which became the textbook and code of those who emulated their achievements in prosecution elsewhere. The charges of heresy and witchcraft, it is true, were almost interchangeable, and accusations of witchcraft were brought freely against heretical sects; but it is difficult to accept Dr. Summers' view that the Bull of 1484 was directed against heresy alone. The various activities of witches are specifically enumerated: the renunciation of the faith is mentioned as an added crime, not as the head and front of the offending, however much importance may attach to it. In order to support his view that the witch as heretic was the object of the Church's attack and that the outburst of witch prosecutions of the fifteenth century was no new thing, Dr. Summers cites earlier Bulls of the popes and refers to earlier heresy trials. Among these he quotes an account of an assembly of Manichees at which the devil appeared. These Manichees were condemned by a synod at Orleans in 1022. But a similar account, almost identical in wording, appears in Walter Mapes about the Paturini, and much the same sort of accusation was brought against the assemblies of most of the many schismatic sects which sprang up about this time. It has all the flavour of a commonplace of ecclesiastical scandal and gossip which was fastened on to any sect that was forced by circumstances to meet in secret. Dr. Summers, however, is convinced of the connexion of heresy and witchcraft. He says:" The full fury of the prosecution burst over England . . . shortly after the era of a great religious upheaval, when the work of rehabilitation and recovery so nobly initiated by Queen Mary I. had been wrecked owing to the pride, lust, and baseness of her sister. In Scotland, envenomed to the core with the poison of Calvin and Knox, fire and cord were seldom at rest. It is clear that heresy had brought witchcraft swiftly in its train." In Ireland, on the other hand, for obvious reasons, "the devil's claws were finely clipped."It is not possible here to follow Dr. Summers in all the consequences which are entailed by this acceptance of the purely heretical character of witchcraft and the orthodox attitude of the Roman Church towards such matters, which almost necessarily involves the view that at the present day witchcraft persists in the celebration of the black mass, satanism, and spiritualism-a conclusion which an anthropologist at least would find it difficult to accept, for psychologically and culturally they are poles apart. It explains why he traces witchcraft back to the Gnostics and the Manichaeans, and also why he rejects the anthropological view. His rejection of the contribution of anthropology to the study of witchcraft might carry more weight had it been clear that he is fully aware of what that contribution is. The anthropologist no longer accepts, if he ever did, " devilworship," the term used by Dr. Summers, as an adequate description of a primitive cult, secret or other; nor incidentally is 'Bantu' a territorial term. The belief in the witch is widespread in time and space. Possibly its origin may go back to paleolithic times. The animal-headed human figure depicted in the cavern at Les Eyzies, or the leader of the dance in the paintings of Cogul, may be the ancestors of the leader of the coven. Witchcraft exists to-day among both primitive peoples and the peasant populations of Europe. At a time of universal credulity it was elevated by the Church, as a self-protective measure, into a heresy; but that does not place it outside the scope of the science which studies the beliefs of man as objective facts of experience, or remove it from the category of primitive religions, even if it survived only in a mutilated or attenuated form.In conclusion, although there are still many controversial points upon which it has not been possible to touch, it must be said in fairness to Dr. Summers, and to those who are interested in one of the most extraordinary chapters in history, that notwithstanding the point of view from which the book is written, and the bias which has determined the line of discussion of the origin of the belief, this is the best and most complete account of the witch cult in medieval and early modern Europe which has been written in recent years.

ISSN:0028-0836    

DOI:10.1038/119882a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

TUNGSTEN is a metal which presents so many points of special interest both from the practical and the scientific aspect, that a treatise dealing with it in detail is welcome. From the time when tungstic acid was first prepared by Scheele in 1781 and Bergman soon afterwards isolated the metal, tungsten remained a rare metal, and it only began to assume industrial importance as the result of the work of Oxland in 1847-57. The important position which the metal now occupies, both in connexion with the electric lamp industry and for the production of high-speed tool steel, is an often-quoted but none the less instructive example of the way in which a curiosity of the laboratory may become a valuable product of industry. Apart from this historical interest, however, the properties of tungsten itself are remarkable. The metal, at room temperatures and slightly above these, is chemically inert, and uses based on its resistance to oxidation and to chemical attack are numerous and important. Its application to electric contacts may be recalled. On the other hand, at higher temperatures, tungsten becomes chemically much more active, combining readily with oxygen and even exerting a strong reducing action on the oxides of other elements. For this reason, both in the manufacturing processes applied to it and in its practical applications at elevated temperatures, it must be kept out of contact with oxygen or other oxidising agencies. As a result we find that it is hot-worked usually in an atmosphere of hydrogen, or maintained in a vacuum or in an inert atmosphere such as nitrogen or argon. Tungsten is remarkable from yet another point of view. If we take account of what may be termed the 'relative temperatures ' of metals, tungsten at room temperature must be regarded as one of the I coldest' substances which it is possible to obtain; i.e. it is further removed from its melting point than any other metal. Since the properties of metals are closely associated with their ' distance ' from their melting points, it is not surprising to find that the mechanical properties of tungsten are correspondingly extreme. At room temperature it is probably the strongest known material, and it can be produced in a ductile condition only in special circumstances. When thus produced, however, it can be cold-worked and work-hardened like other metals, but with this difference, that plastic deformation applied to it at any temperature much below 1500° C. still produces work-hardness. The re-crystallisation normally associated with annealing only occurs above that temperature, which thus corresponds roughly with, say, 5500 C. for iron. Finally, tungsten cannot, like other metals, be melted and cast, since its melting temperature is so high that it is not yet possible to obtain a refractory capable of holding molten tungsten. It remains to be seen whether this will yet be accomplished, or whether it will be worth while. Dr. Smithells states that tungsten which has been fused is rendered permanently brittle, but recent work on other metals at least suggests that such brittleness may be due to the presence of traces of inter-crystalline impurities which readily escape detection.Meanwhile, the process of manufacture of ductile tungsten is again of special interest. Like wrought iron, the metal is brought into a coherent solid form by the high-temperature welding of small particles without previous fusion. The metal is obtained in the form of powder, of the desired degree of purity, and this is welded into the form of rods by heating the compressed material in an atmosphere of hydrogen and then 'swaging ' it while hot. The rods thus produced are 'sintered' by heating them electrically by the direct passage of a heavy electric current, and the material thus consolidated can then be worked down, while hot, by further hammering. Ultimately it can be drawn down to exceedingly fine wire in the cold. Perhaps the most curious fact of all is that such wire shows a considerable degree of ductility, but is rendered completely brittle by heating it up to or beyond 15000 C. The proximate explanation is that in the cold-drawn wire the crystals are elongated into long fibre-like bodies, so that bending or twisting of the wire implies deformation of the crystals themselves, but little or no relative motion between adjacent crystals. After annealing, the crystals resume an equi-axed arrangement, and any plastic deformation implies considerable relative movement of the crystals with the result that, at room temperature, rupture immediately occurs. This phenomenon has been interpreted, both by Z. Jeffries and the present writer, in terms of the 'amorphous cement ' theory, according to which there is a thin layer of non-crystalline metal between adjacent crystals. At temperatures very far below the normal melting point of the metal, this amorphous layer is brittle and incapable of even a minute amount of flow. A similar phenomenon occurs in iron at very low temperatures. The question just briefly discussed is an example of the way in which the behaviour of tungsten is apt to become the testing-ground of theories of the structure and behaviour of metals in general. In fact, a considerable portion of Dr. Smithells' book, and perhaps the most interesting portion of it, is devoted to an account of a series of researches of a general fundamental nature in which tungsten has served as the material for experiment. In view of the difficult technique, often involving the use of very fine wires and of exceedingly high temperatures in high vacua or in carefully controlled atmospheres, it is surprising to find the degree of success which these investigations have attained. The researches of Goucher and of Smithells himself are excellent examples. The only misgiving is whether tungsten, which differs in so many remarkable ways from other metals, is the best choice for work of this kind. No doubt the most fundamental phenomena are common to all metals, but each of them has its own peculiarities, and tungsten perhaps more so than the majority.Dr. Smithells' book deals with the various matters already mentioned, and many others bearing on the manufacture, properties, and applications of tungsten in a lucid and interesting manner. The matter of the book is selected in a way which speaks at once of the fact that it is the work of a man writing on his own subject, largely on the basis of direct personal knowledge, and the book is to be valued accordingly. The only section to which this does not apply so fully is that relating to the use of tungsten in alloy steels. No doubt this section has been included for the sake of completeness, but it is not on the same level as the rest of the book. One can scarcely blame Dr. Smithells because he is not also an alloy-steel metallurgist, but it might have been wiser to omit this section. Finally, the photo-micrographs of tungsten which are given in the book deserve a word of praise. They frequently represent sections of very thin wire wound in spirals and have been obtained by an ingenious technique used with great skill. Fortunately, the structures encountered in a pure or nearly pure metal like tungsten are sufficiently simple to be readily understood by the technical reader even if he is not a trained metallographer. On the whole, Dr. Smithells' book is to be commended as a clear and well-written monograph on a subject of great interest

ISSN:0028-0836    

DOI:10.1038/119884a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

(1) THIS attractive volume, printed and illustrated with the expensive excellence that is found so frequently in American publications, is a prelude to adventure in a scientific sense rather than a record of completed researches. While this is true up to a point of the actual work accomplished, the summing up of the knowledge concerning all the matters touched upon is vividly and skilfully done, so that the reader is presented with the state of knowledge in connexion with the matter in hand in relation to the particular experience and contribution made by the members of the expedition. This is well shown by the very interesting account of yellow fever. Scarcely any cases occurred during the period spent by the expedition in Brazil; the preventive measures, and probably also a spontaneous remission, have resulted in the almost total disappearance of the disease. The writer, however, summarises the studies carried out on the last epidemic at Bahia in 1923, and concludes that the evidence incriminating Leptospira icteroides was strengthened and the identity of the yellow fever occurring in Palmeira and Bahia with that which is found in Mexico, Peru, and Colombia was established. Among the medical matters investigated, the chapter on malaria and splenomegaly is of particular interest. Malaria, in spite of quinine and of all the knowledge that has been accumulated in the last thirty years, remains the most prevalent and serious disease of Amazonia, as indeed of practically all tropical and many subtropical countries. It is true even now that the disease is accepted fatalistically in countries much more civilised and better administered than that traversed by the expedition. The workers show the wide experience that they bring to the problem, which is well handled, and the ravages of the disease as an agent of human degradation and of actual depopulation of considerable areas are forcibly and eloquently described.The chapters dealing with insect life are, as might be expected, of great interest, tropical South America being a naturalists' paradise in this respect. Simulium and Tabanus were found in large numbers, and are reported upon in some detail. The summing up of the role of Tabanus species in the transmission of disease, especially protozoan diseases such as trypanosomiasis, is judicial and well informed. The problem of the transmission of the trypanosome of Mal de Caderas remains, however, unsolved. The expedition, as has already been shown, had a happy and catholic taste in knowledge, and there is an excellent account of a new dipterous fly Malacophagula neotropica (Bequaert), parasitic in a snail. This chapter also gives an account of the arthropod enemies of snails.(2) If the report of the Hamilton Rice expedition cast its net in a wide and leisurely way into a sea of tropical life, and brought back a mixed catch which is set out with a truly scientific interest in knowledge for itself, the second book to be considered deals with the wide range of its subject in a totally different spirit. In "Animal Parasites and Human Disease," Dr. Chandler takes his title to heart from the first page, and we are considering animal parasites and animal life strictly from the view-point of the doctor and the sanitarian. The author knows what he is about, and the preface states the position with admirable clarity. It purports to give the results of scientific research in this particular field in such a way that it shall be useful to those who seek to apply them to practical problems. Dr. Chandler is inclined to reprove the scientific worker for his failure in propaganda, but this vivid, condensed, and readable treatment of the subject is itself a proof that the task of exposition is probably better executed by those who are applying the fruits of inquiry rather than by those whose energies are absorbed in the pursuit of new knowledge.There is here quite frankly a different attitude towards knowledge, and the energetic insistence of this type of statement requires gifts which differ from those usually possessed by the research worker. The book succeeds in its aim. It contains an enormous amount of information; it deals with all the protozoan parasites of man, their life-histories, means of transmission, and with the history of the insect vectors-this last section is particularly well done considering the scope of the book. All the spirochetes of man are described; all the ' worms ' parasitic in man, with a brief chapter on leeches, and all the arthropods which are either parasites of man or suck his blood, are included; and all this is achieved within the compass of 528 pages. It is in the main a very accurate and fair presentation of the case, and if there are some rather sweeping generalisations and a slightly optimistic sense of progress and achievement, as, for example, in the account of malaria, it is nevertheless a sound and valuable book and excellently suited to the reader for whom it is designed.One wonders if such doubtful forms as the Chlamydozoa and Cyclasterion scarlatince are worth including in this book, but the fact that they are mentioned gives a measure of the completeness with which the author has dealt with the subject. These two books are an interesting comment upon each other, for the Hamilton Rice report reveals how lamentably the use of knowledge lags behind its possession.

ISSN:0028-0836    

DOI:10.1038/119885a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

(1) APPLIED photo-electricity has perhaps developed more rapidly than any other branch of applied physics. The discoveries of outstanding importance which have resulted from photo-electric, observations have stimulated the production of improved apparatus, and this has had a healthy reaction upon practical applications. Of these, telephotography and television are among the most interesting. Of the former, Mr. Thorne Baker was one of the most distinguished pioneers, and it is well to have a book on the subject from his pen. The various methods of picture transmission, such as those of Bakewell, Caselli, Charbonelle, Korn, Belin, and others, are described, but considerably more might well have been said about the code method by which Sanger Shepherd transmitted the race for the America Cup. A great deal is naturally said about selenium, and most of it correctly, though the date of discovery of its light-sensitiveness is given as 1861 instead of 1872, and the very prevalent mistake is made of describing it as particularly sensitive to red light, the great response to which is solely due to the abundance of energy in the red end of the spectra of most terrestrial sources. The successes achieved by Korn with his selenium transmitter in 1907 have almost been forgotten; the speed was five seconds per line, in spite of the 'lag ' of selenium. Portraits were transmitted between Paris, London, and Berlin, of a quality suitable for newspaper reproduction. More recent methods, employing photo-electric cells with a million-fold amplification, maybe somewhat speedier but scarcely give a better quality, though giving more detail. The method worked out by Mr.Herbert Ives, of the American Telegraph and Telephone Co., is particularly interesting in view of the fact that it has recently been successfully applied to television. The difficulty of synchronisation is in this case got over by phonic wheels at the sending and receiving stations, both controlled by the same tuning fork.(2) Mr. Dinsdale's booklet purports to give a general statement of the problem of television and the various attempts to solve it. Much is said about the results achieved by Mr. J. L. Baird, and said in a rather rhetorical manner, without, however, giving sufficient data to judge of the originality of the method adopted. But at a time when the solution of the problem is being achieved simultaneously along different lines, it is useful even to have a partial description of one of the successful systems.

ISSN:0028-0836    

DOI:10.1038/119887b0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THIS little book is a continuation of the series of books by Dr. Hale, of which " The New Heavens " and " The Depths of the Universe " were the first representatives. Like those volumes, it forms an edition de luxe of three articles which originally appeared in Scribner's Magazine: their titles are- " The Oriental Ancestry of the Telescope "; " Heat from the Stars "; "Beyond the Milky Way." They are plentifully illustrated by excellent photographs and diagrams, and the volume in every respect reaches the high standard set by its predecessors.The contents of the chapters have already been separately noticed in NATUTRE on their first appearances, so that little of a descriptive character need be said. It is unnecessary also to comment on the accuracy and lucidity of style of a book by Dr. Hale. His main purpose in this excellent little series is " to tell of some of the principal advances of my associates, with such historical background as to render their significance clear," but that he is not rigidly restricted by the terms of this statement is shown by the fact that the first chapter of the present volume has been constructed, as he says, from material gathered chiefly in Egypt and England. The book will be found useful, not only by the general reader, for whom it is evident that it has chiefly been prepared, but also by workers in astronomy who often feel the need of authoritative statements on matters of current research, disentangled from the mass of detail in which they are necessarily involved in the original publications. A new attitude to the problem of variable stars is inevitably induced in the reader by the direct statement that " while to the eye X-Cygni is 10,000 times as bright at maximum as at minimum, the total radiation as measured with a thermocouple undergoes a variation of only 1-7 times." We hope that Dr. Hale will continue to enrich the literature of astronomy by further additions to this admirable series.

ISSN:0028-0836    

DOI:10.1038/119888b0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

.IN attempting to give an account of the development of civilisation from the end of the paleolithic age to the bronze age in Europe and adjacent regions, within the compass of this small volume, Mr. Burkitt has essayed a very difficult taskdifficult in more ways than one, for the material does not lend itself easily to systematic treatment. It has not been worked over and classified to the same extent as the material of the old stone age, and in the later stages the problem of dealing with a multiplicity of detail of which the bearing is often still obscure is complicated by ethnologicalquestions to which the answers are still very much at the hypothetical stage. All credit is therefore due to Mr. Burkitt for the success with which he has carried out his task, even though in its later pages his book suffers from over-condensation and lack of space for adequate discussion of many doubtful points. Probably to most of his readers much of the material relating to the copper and bronze age will be seen in a new perspective, while the chapter on art brings together material which is usually scattered. It gains greatly in significance by the author's method of treatment.

ISSN:0028-0836    

DOI:10.1038/119889b0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

HAVING read the interesting criticism in NATURE of May 14 of the annual report of the Oversea Settlement Committee, may I, as a member of that Committee, be permitted to make certain comments?It is claimed that the report fails adequately to cover the field of activity of the Oversea Settlement Department, and that no mention is made of many of the various factors that bear more or less directly on the question of the settlement of our people in the Dominions. The answer to this stricture is twofold. In the first place some of our earlier reports cover a wide range; but in a time of transition like the present there would be great difficulty-in fact danger-in attempting to forecast, for example, the economic results from different types of farming. Secondly, our reports are intended primarily for Parliamentary use, and are not intended for purposes'of propaganda or to furnish information to would-be settlers. The latter functions properly belong to the handbooks on the various Dominions and Colonies which are prepared and issued free to inquirers by the Department. These handbooks which, it may be said, are compiled with the utmost care and are revised twice yearly, contain much of that information we are charged with omitting from our report, where its inclusion would be quite impracticable, if only on the grounds of bulk and expense.The O.S.C. has no widespread policy of propaganda, for the simple reason that, without it, there are more migrants willing to leave our shores than the Dominions can at present absorb. This point should be clearly understood-the volume of migration from Great Britain is governed by the absorbing power of the Dominions.In regard to this power of absorption, I would point out that the article in NATURE overlooks the fact that New Zealand, per head of her population and pro rata for her area, places far more settlers than any other Dominion. One reason for the small numbers who migrate to South Africa is that more capital is required there than is the case in the other Dominions. There are other reasons as well that it is inexpedient to discuss.One very important point raised in the criticism is that of the suitability of previously inexperienced men for settlement upon the land. We can say quite definitely that, given the right conditions of settlement, inexperienced men can and do succeed well. The Group Settlements of Rochester and Shepperton in Victoria, Australia, are convincing proof. Started in 1910, with the settlers drawn almost entirely from our great cities, these are to-day well-developed and flourishing communities. But this form of settlement, though in the long run economic, entails heavy initial expenditure. On the other hand, to place townsmen on the land as isolated units and without adequate training and supervision is to court failure. The comments upon the part education should play go to the very root of the matter. There is nothing to be gained by shutting our eyes to the fact that since the foreign migrant has a far more highly developed 'land sense' than the British migrant, less has to be spent upon looking after him during his early years. So far as I am aware, foreign Governments do not, and have no need to, give grants in. aid of migration. But we have to deal with the fact that the drift to the town is more accentuated in the case of the Anglo-Saxon than with other nationals. Considerations of national safety demand that that tendency should be combated. If we are to develop the empty spaces of the Empire by men of our own race, we must take the necessary steps to guide cultivators of the soil to those areas. A high degree of organisation and the full co-operation of all the Governments of the Empire is called for; and such organisation will cost money. We must maintain balance. Such effort does not preclude the migration of thousands of men who will not go upon the land, but it will be fatal if the agricultural side be overlooked.

ISSN:0028-0836    

DOI:10.1038/119890b0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

MANY methods have been devised for the investigation of the evaporation of sea water, but of them all only those can be applied aboard a ship in which errors caused by the rolling of the ship are prevented. Therefore the method invented by Dieulafait and modified by Penck and Merz has largely come into use. The authors mentioned measured the quantity of evaporated water by observing an increase of the concentration, or density, of the salt solution.Evidently, however, such an increase must always be very small, because the concentration itself of the salt in the sea water is usually equal, to 30-37 per thousand. For example, Merz and Wiist were obliged to wait 12-24 hours before it was possible to make a good observation of the increase of concentration. During such a long time all the meteorological conditions may be altered and the temperature of the evaporating water will change. The simple method which I describe here is free from all these defects. It is based on the observation of the cooling of water caused by evaporation.The sea water must be poured into a so-called Dewar vessel of a special form, represented in Fig. 1. The thermometer T gives the initial temperature, when the instrument is closed with a cover C. When the latter is opened the water will begin to evaporate through the action of the wind blowing over its surface. The latent heat of evaporation, specific heat of water, the volume of the vessel, and the area of the water level are known. It is easy, therefore, to calculate the quantity of water which evaporates in 1 sec., per unit area, but only if the mean temperature of the water-before and after evaporation-is equal to that of the air. The interval of time sufficient for the perceptible cooling of the water usually does not exceed a few minutes, the thermometer scale showing not smaller parts than fifths of a dearee.The temperature of water is usually higher than that of the air. In such cases one must draw the curve of cooling (Fig. 2). The ordinates of this diagram represent the temperature of the water, and abscissue either the time or the " distance which the air-particles travelled in the wind." This latter case occurs when the velocity of the wind varies strongly during a short period of time. (For further details on this question see my article mentioned below.) We will now consider only the case of constant velocity of the wind. Let us denote the temperature of the water by t (to being the temperature of the air) and the time by T. Then it is evident that the velocity of evaporation is proportional to dt/dT, calculated for a point of the curve, where t = to. To the same quantity (dt/dT), is proportional the quantity of heat which is lost by the water. If we calculate analogous quantities for other points of the curve (in Fig. 2), we shall obtain data for the study of the thermal interchange between the sea and the air: if the temperature of the former is greater than that of the air, there will be a more rapid cooling of the water; conversely, the cooling down will be retarded. From such observations can be deduced the law of thermal interchange, a law of very great importance for geophysical problems.A great number of observations have been made by me from the Black Sea, over the Mediterranean, Red Sea, Indian Ocean, to the China and Japan Seas, from July 1925 to March 1927. The results of the measurements of the evaporation and thermal. interchange will appear in Gerlands Beitrdge zur Geophysik. The instrument used for these measurements was suspended on Cardan-rings, as is shown in Fig. 1 , A is the anemometer, placed on the same level with the water in the vessel. With an analogous instrument one can measure the evaporation of water immediately from the level of the sea or of the lake; in this case it must float in the water so that the edges of the Dewar vessel just touch the water-level. Thus it is possible to find the connexion between the evaporation from a vessel on board a ship and the evaporation in natural conditions. It is understood, of course, that such experiments can be made only when the water is sufficiently calm.

ISSN:0028-0836    

DOI:10.1038/119891b0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

MISS BUER'S letter in NATURE of May 7 removes the difficulties which I felt in accepting the reviewer's statement that the rise and population in England after 1750 was due to the introduction of inoculation and a consequent decline in infant mortality.I am, however, mainly interested in the industrial history of Great Britain in the first half of the eighteenth century, and here I still think that Miss Buer has underestimated the influence of the Colonial trade upon developments in the west of England. In her chapter on commerce Miss Buer says that " Bristol and Norwich were stationary and Liverpool had hardly begun to be." The chroniclers of Bristol (Nicholls and Taylor, for example) do not support this statement. Bristol, it would appear, had been growing in importance long before 1750, and this prosperity had extended beyond the City walls. In 1756, Dean Tucker estimated that the proportion of iron manufacturers-that is, smiths to iron-makers-was two thousand to one. The former were using largely American bar iron, but the iron industry had already moved from the Weald to the west to be in a position to supply this growing market. Hence it is probable that there was in the first half of the eighteenth century a considerable redistribution of population in Great Britain-some depopulation by the southern counties being more than offset by an increase in the western area.

ISSN:0028-0836    

DOI:10.1038/119892c0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature