摘要:

PUBLIC opinion is inclined to look upon the P scenery and great natural monuments of a country as of the order that lasts for aye, and to imagine that their survival through many millennia betokens an infinite future. It little realises that in this and other civilised countries, human progress is constantly nibbling at the works of Nature, and that greatly as the rate of consumption has grown in recent years, the threat will undoubtedly be magnified in the years to come. The need of watersupplies for the centres of population has altered lakes and swamped valleys; the demands of industry have changed rivers and harnessed waterfalls; the vast requirements of the modern metalling of roads are cutting into the 'everlasting' hills; and the desire for speedy transport has driven and threatened to drive bleak roads through some of the select scenery of the land. With all this there has been, of course, immense economic gain, but there has also been loss. There has been a loss of beauty, a destruction of things of sthetic and artistic appeal; and who knows what unconscious influence these may have had upon the minds of men ? But there has also been a loss to science, sometimes material, more often of those historic-sentimental records, which, linking the achievements of the past with present-day knowledge, stir the imagination and stimulate the broad view. The haunts of a dwindling native flora and fauna are being disturbed: the driving of a road (abetted by the importunities of collectors) banished the Artaxerxes butterfly from its first discovered site in the King's Park, Edinburgh, which had "stocked the cabinets of Europe." Just as in Italy the Barma Cave, the richest and most interesting of the Grimaldi caves, which have added so greatly to the knowledge of paleolithic man, has been exploited for building stone, so the M'Arthur Cave at Oban, the first recognised habitation of Azilian man and, until the discoveries of last summer, the oldest known human dwelling in Scotland, has been entirely quarried away. The historic rock on Blackford Hill within Edinburgh, on the smoothed surface of which Agassiz first detected indubitable traces of an ice age, is threatened by the road-metal excavations of Midlothian County Council, and similar operations in Haddingtonshire will eat into Traprain Law, the site of extensive Celtic settlements and of the discovery of a unique silver hoard belonging to an early century of our era.Here is a clash between 'business' on one hand and aesthetics and science on the other. Obviously so disintegrating a warfare ought to be stopped, but how ? Not by a simple attitude of protest, for the claims of 'business ' cannot be lightly brushed aside, and the county council 'steam-roller' has an effective way of overriding objections. A burst of local effort endeavours to meet each new aggression, and occasionally a treasure is saved. Stybarrow and Glencoin Woods in Ullswater have thus been rescued within the last few weeks, and the Times of Feb. 5 announced that negotiations were understood to have reached a successful issue " whereby the land on the west side of the Borrowdale road, from Peterfield to the entrance to Stable Hills Farm, will be saved from all possibility of being built on, and the uninterrupted view over Derwent Water into the famous 'jaws' of Borrowdale and across to Cat Bells will be preserved intact for all time." In both cases appeal is made for public subscriptions of considerable amounts, necessary if successful negotiations are to be converted into the full goal of permanent preservation. More often, however, the 'steam-roller,' if checked at all, is only temporarily checked and soon returns to complete its work. A year or two ago the danger seemed to have been turned from Traprain Law, but now preparations for extensive quarrying on part of the hill are in full swing. On the whole, local effort is too little organised, too spasmodic, too late in getting into action, too lacking in persistence and in authority to deal efficiently with such emergencies.The needs of industrial progress are clamant and cannot be gainsaid by a point-blank negative, but is there no room for compromise ? Compromise implies give and take on both sides; what has the esthetic and scientific side to bargain with ? As the law of Britain stands, it has nothing; for though more than twenty years ago France passed its first law towards the protection of ' sites pittoresques,' in Great Britain public opinion remains the only support. The matter seems to rest upon the nature of property in land; does purchase or possession imply for the possessor an absolute right to deal anyhow with the land he possesses ? We act as if possession held this absolute right, and as if only by special appeal or through special favour may the right be waived; but ideas are changing and have changed. The absolute right no longer holds in the great cities, where an owner may not build upon his land except in accordance with the interests of the community as expressed by the Dean of Guild Court or some similar body. The time will come when a natural monument, whether its message be asthetic, historic, or scientific, will be reckoned of as much value as a garage, and its preservation or destruction a matter not for the individual but for the nation.Other countries, recognising their value in the national life, have moved or are moving towards a general conservation of the natural sites and monuments of artistic, scientific, historic, and legendary interest. A vast body of evidence in this sense was submitted to the " Congres international pour la Protection de la Nature " held in Paris in the summer of 1923, and appears in the " Rapports, voeux et r6alisations " of the Congress published in 1925. In 1906 the loi Beauquier, which provided for the classification of picturesque sites, particularly forest areas, by a special commission in each department, and for the safeguarding of these places, set the ball rolling in France. Since then various measures of preservation have been applied to the colonies of France by decrees of the colonial minister. In Switzerland, Spain, Poland, Jugoslavia, Hungary, and Russia the movement is strongly supported. In Great Britain spasmodic efforts have become crystallised in the Royal Society for the Promotion of Nature Reserves in the British Isles, and it has already done good work. We trust, however, that the lack of faith in the efficacy of parliaments and governments as protectors of the beautiful and interesting, expressed at the Paris conference by the president, Viscount Ullswater, does not mean that this influential society will refrain from impressing upon the government of the day the desirability of safeguarding natural monuments, until parliamentary recognition gives a national sanction far more effective than that of any private organisation could be. If, as we assume, a method of compromise between industrial needs and the demand for the picturesque or significant will ultimately replace the spasmodic and point-blank opposition of the present, who is to arrange the compromise ? It must be a body with authority, with knowledge, and with sympathies broad enough to gain the confidence of both sides. Local authorities are already sufficiently burdened with duties, and their very proximity may be apt to obscure the broad view.In France the Government appointed a special commission for the precise purpose, and this would seem to be the most satisfactory method. We need a Nature Monuments Commission, an advisory body attached to one of the great departments of Stateb, with the needful statutory backing. This body, with such local help as could be obtained, might draw up lists of Nature monuments and haunts of rare animals and plants deserving of preservation, but a chief function would be to receive from recognised local bodies complaints of threatened destruction, and to decide whether the particular needs of economic development were such as to demand the sacrifice of a national asset, or whether some adjustment might be arranged so that whole or part of the threatened natural monument might be preserved.Unti] recent years the handiworks of prehistoric man and his successors existed in Great Britain unprotected from the elements or from the despoiler (except where private ownership bestirred itself), and, as a consequence, hundreds of stone circles of the bronze age and prehistoric sepulchral cairns, as well as buildings of Roman or later times, have been demolished and converted into stone dykes and insignificant barns, byres, and cottages. But the creation by government of an Ancient Monuments Commission has saved the situation, and invaluable work has been done by this body in scheduling and protecting the irreplaceable relics of the former inhabitants of Britain. Here is a precedent for the creation of a Nature Monuments Commission, and here in many ways is a model for its labours.

ISSN:0028-0836    

DOI:10.1038/119265a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THE normal chemist is so well used to seeing This reagents pass away in a decently continuous fashion, that when he finds them attacking each other in a succession of recurrent spasms, he is a little apt to shy off. The thing is, perhaps, too nearly suggestive of heart-beats, of vital processes, and of human activities: domains into which chemists are warier of intruding than formerly, and which they prefer to leave to their bolder brethren, the physiologists and the historians. At all events, rhythmic, pulsating, or periodic reactions have seldom been systematically followed up in any general way by chemists. There have been, it is true, such detailed inquiries as Ostwald's on the periodic dissolution of a specimen of chromium in acid, as Bredig's on the pulsating decomposition of hydrogen peroxide by mercury, and as the numerous studies of the Liesegang effect in jellies; but Dr. Hedges and Dr. Myers have now worked their way to a more comprehensive survey than these, which they have summarised in a small monograph. The broad plan of this is, first to classify periodicities of various sorts, then to set forth the experimental factors that operate in each class, and to give in the end an indication of the views which the authors-themselves notable experimenters in the field-have formed as to underlying causes. The full and important bibliographic index contains about 300 references, of which about one-third centre in the Liesegang phenomenon. About twenty fall outside the last thirty years. The kinds of periodicity discussed are shown by the authors' definition of the word: " the recurrence of some property or accentuation of a property at regular intervals of time, distance, or other quantity." The sub-atomic recurrences that give rise to periodicities such as Mendelkeff's are intentionally excluded. Three main classes may be distinguished. In one, the speed of a chemical reaction shows pulsations, time being here the variable; in another are the reactions or properties in which space is the variable, so that fixed spacepatterns are formed, like the layers in an agate; and in another class the variable to which the pulses in properties are referred is not obviously time or space, but some adjustable condition such as degree of dilution or extent of mechanical stress. One example of the third class is Holker's effect, in which a row of tubes of a colloid solution show alternating groups of 'thick and clear' when each tube is given a stronger dose of electrolyte than its left-hand neighbour had. Another example placed in this category (labelled " static periodicity ") is found in the waxings and wanings of the mechanical and other qualities of some metals when subjected to continued cold-working.The second class includes all the phenomena first studied thirty years ago by Liesegang: the stratification caused by the advance of a reagent into a jelly containing a second reagent. The valuable critical survey of the work in this class shows that although stratification is favoured by the presence of jellies, these are not essential to it. It can, for example, occur by the slow merging of gaseous ammonia and hydrogen chloride; yet even here it is to be noted that the smoke produced is a colloid, and so are the glass reaction-tubes. It is obvious, in all cases, that a prime necessity is that diffusion must be going on, and to that extent time-rates must come into the affair; but the authors say that there is nothing to suggest that the reaction-time curve itself is periodic. They are inclined to correlate the formation of Liesegang strime with Holker's effect, already mentioned. Though much diverse work has been done, there is evidently much still to do before a full understanding is reached of the Liesegang phenomenon and, with it, of many structures that concern mineralogists and biochemists. The authors' survey will be very helpful to workers in this field. The account of the work on periodic reactionspeeds, together with that on pulsating electrodepotentials, covers very interesting ground. Here the authors, in their own investigations, met what they call " the bugbear of work on periodic phenomena "; namely, the operation of essential but unidentified factors. This has led many other workers into puzzles and controversy; but Drs. Hedges and Myers' happy gift of devising crucial experiments has often enabled them to exclude irrelevant factors and to study the phenomenon at its simplest. For example, aluminium dissolving in alkali gives off hydrogen in pulses; is this merely due to the formation and subsequent discharge of supersaturated solutions of the gas, either in the metal or in the liquid ? They make the aluminium one electrode of a cell containing the alkali; when it is made the anode, it dissolves and the hydrogen comes off in pulses-but at the other electrode; and when the aluminium is made the cathode, so that it does not dissolve, hydrogen is evolved from it-but smoothly. Hence the question is negatived. Again, it was found that certain cases of dissolution owed their periodicity to something in the glass walls of the containing vessel; and when the glass eventually 'tired,' periodicity could be restored by minute traces of various colloids. Eventually, the very important conclusion next mentioned was reached.The core of the book is this: the authors show fairly conclusively that intermittent pulsations in a reaction A + B are due to the presence of some substance, C, which must be in a certain special physical condition. This substance may be foreign to the net reaction; for example, metallic mercury will cause the spasmodic decomposition of hydrogen peroxide; but alternatively it may be one of the reagents themselves, appropriately treated beforehand. To mention one case, the dissolution of copper in a suitable acid goes by pulses if certain freshly made colloids are present, or alternatively if the copper itself has first been submitted to mechanical stress. The soft crystalline metals like lead and tin are not able to be activated for periodicity by being strained; the authors connect this with the faculty for self-annealing. With metals which have been only mildly strained, the property is apt to fade. Liquid mercury needs no special treatment; it is active without it. What clearly emerges is that the seat of pulsation in a heterogeneous action is at an interface. Further, there are good reasons for suspecting that, despite some seemingly contrary evidence, no pulsating reaction is other than heterogeneous.Drs. Hedges and Myers accordingly seek to go further; and, tentatively but suggestively, they refer rhythmic reactions, and rhythmic structures also, to effects of varying surface tension. There is evidence that this property, which itself affects reaction-speeds in a solution, can be a periodic function of the strength of a solution; and a valuable step forward will have been made if pulses in surface tension can be correlated with reaction pulses on one hand and with the Holker effect (and through it with the Liesegang phenomenon) on the other. It still remains to explain why periodicity of any sort should occur at these surfaces. The evident connexion with catalytic action is commented on by the authors; but they seem to think that rhythmic movements of energy may be intrinsicin 'metastable' surfaces. It is quite possible, they say, that all catalysis is periodic in character, though only rarely measurably so. Many readers will probably argue that the factors which must, in that event, be invoked to explain the suppression of rhythm in innumerable observed cases, might just as well be used instead to explain its presence in a few. That is, we would make rhythm a result of superposed velocities, rather than stop short at a' principle of periodicity.' Thus the reaction velocity in a volume of dilute reagents subject to catalysis at fixed surfaces in it will show pulsations, provided that the catalytic activity of the surface gradually increases until it causes a local ' explosion,' i.e. a reaction speed that outstrips the rate at which reagents reach the catalysing surface. An example is seen in the lecture experiment, wherein a heated platinum wire is hung above warm ammonia solution through which oxygen passes; the rhythm of accelerating catalysis culminating in explosion, with local exhaustion of the reagents and the renewal of the cycle, can be watched recurring for a long time. The molecular film-patch mechanism of surface catalysis, worked out by Langmuir and others, seems capable of describing conditions for such cases. At the same time it is attractive to look upon a pulse inductor as a kind of bank of energy, as the fly-wheel of an engine; for it does behave as if it stored up energy gained from the reaction, delivering it again so as to stimulate the adjacent reaction when this would otherwise have slowed down. In this light we may survey Drs. Hedges and Myers' conclusions as to the physical texture needful in a pulse inductor. Collating their facts as to cold-worked metals and colloids, they believe that a metastable, amorphous form is essential. They do not clearly differentiate metastability from amorphism; definitely crystalline, but metastable, allotropic forms of metals do not happen to be mentioned as pulse inductors; but the case of liquid mercury acting in this way shows that the potential energy, which characterises a metastable variety, need not have been implanted in the substance by previous treatment, but may be gained from the reagents into which it is put. The factor common to pulse inductors might be crudely described as the ability to produce atoms the valency-bonds of which stick out of the substance. Thus it can be said that a pulse inductor deals out to the adjacent molecules some of its internal energy, derived from external sources and set free by the return of its own atoms to a more stable orientation.An illuminating example of this 'relaxation' is quoted on p. 65; cold-worked copper spontaneously ' breathes ' oxygen in and out for a long time; whereas stable copper under the same conditions scarcely takes up oxygen at all. One may perhaps be allowed to picture this, however imperfectly, as a slow union of oxygen with areas of active or abnormal atoms of the copper; when the film of oxide molecules has spread to the edge of a patch of normal copper atoms, the transition sets in rapidly at the boundary, which thus quickly invades the oxide film and causes the expiration of oxygen, demanded by the smaller affinity between oxygen and normal copper. A moderately quick renewal, from within the copper, of areas of active atoms would then make the cycle set in again; such renewal requires that energy shall be supplied to the copper from outside, either by previous cold-working, or else by the storage of energy evolved from the stoppage and fixation of gaseous oxygen upon the active atoms. A fairly good analogue is that of a sink, filled by a slow tap and intermittently emptied by a quick-acting siphon; gravitational energy here takes the place of chemical energy. (It would be interesting to know whether the oxygen expired in pulses from copper is chemically active, as hydrogen escaping from palladium, and other molecules newly released from combination, appear to be.) The storage of energy here ascribed to pulse inductors, as it were in a delay-action fuze, may be compared with the similar storage of radiated energy that is seen within silica or fluorite when these are heated after being exposed to highfrequency rays; or, a better parallel here, in the photographic plate between exposure and deve]opment. (In passing, the 'reversed image' of a photographic plate suggests a periodic action.) Thus the time of relaxation can be long in a solid aggregate of molecules while no reagent is attacking the aggregate. In homogeneous systems, on the other hand, it is known from fluorescence measurements that the time of relaxation of the isolated molecules is extremely short; they do not appreciably store up energy, and accordingly, as has been mentioned, measurably pulsating reactions in truly homogeneous systems are suspected by Drs. Hedges and Myers not to occur. These reflections are offered merely as a footnote to a work which gives an admirable experimental survey and classification of facts, new and old, that were in much need of being marshalled and brought to our notice. The book is bound to meet with a well-deserved success; and not among chemists only; the authors remind their readers that periodic phenomena are of high importance biologically. Physiologists, no less than physical chemists, will find here much to think about, even though the book describes no biochemical or biophysical researches; for a good deal in the rhythmic behaviour of the fibres of living tissue is surely connected with the factors that Dr. Hedges and Dr. Myers have found significant in their studies of unorganised materials.

ISSN:0028-0836    

DOI:10.1038/119267a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

LOCAL Education Authorities would be wise L not only to facilitate and encourage investigation into local medical problems by members of their medical staff, but actually to expect and indeed require it. The problems are not only manifold but strangely significant and pregnant. " For here is an expanding physiology, unexplored; here are the very beginnings of disease; here its cause may be searched with some hope; here it may often be prevented; here the physique and education of a nation are in rudimentary form -and whatsoever here be found by searching or proved by experiment becomes forthwith of value to the child, to the community, and to the growth of human knowledge." In these words Sir George Newman, in his eighteenth annual report as chief medical officer of the Board of Education, just issued, points out the immense field of research into the physiology of growth which is offered by the presence in the nation's schools of the whole of the population during the most interesting and important years of development. Although there is now completely established a school medical service throughout Great Britain, with one whole-time school medical officer to 8500 children, but little has been done even to explore this abundant field. Local Education Authorities, frankly, are not interested in the question of research. Their medical staffs are overburdened with difficult problems of administration, and mere doctoring more than absorbs the whole of their available time.The appearance of Dr. Kerr's book on " The Fundamentals of School Health " is therefore especially to be welcomed. Dr. Kerr has been exceptionally situated. Appointed thirty years ago as medical adviser to the most progressive of the provincial education authorities, he was in 1902 appointed medical officer to the London School Board. He was the first medical man in England to appreciate the importance of the subject he deals with, and was the first doctor to make a practice of daily visiting the schools. In 1911 the London County Council, recognising his unique qualifications, created for him the post of Research Medical Officer and, to give him full scope and opportunity, relieved him of all administrative cares. The result of the research of a lifetime is to be found in this very remarkable book, with which there is none other in the English tongue that can be compared. It stands alone, and must for many a day stand, as an incomparable authoritative work.Roughly, the forty-three chapters can be grouped into six logical divisions. First come five chapters which deal with heredity and growth, then twelve chapters dealing with general physical defects of the child, followed by five chapters dealing with mental development and intelligence; then eleven chapters directed to the physiology of the special senses, next five chapters dealing chiefly with problems of administration; and, finally, five chapters on the school environmental conditions of the child, including ventilation, heating, and illumination. It is impossible to do justice in a review to the care and labour which have gone to the making of this book. It is safe to say that it includes everything that has hitherto been learnt in regard to the subject, and much is founded upon original work carried out by Dr. Kerr or under his direction.Of especial value are the chapters on the physiology of vision, upon ventilation, and upon illumination, but perhaps the most interesting are the early chapters dealing with problems of growth. Every one will agree with Dr. Kerr's denunciation of the general practice of treating averages as standards. One feels, however, that the author rather stresses environmental at the expense of genetic influences. Most of us would place the standard of height, for example, " somewhere between the Polish Count and Giant O'Brien," and for girth, " somewhere between the Anatomie Vivante and Daniel Lambert." Not so, Dr. Kerr; he is for Giant O'Brien every time. For Anglo-Saxon standards he draws arbitrarily a curve which is higher than the average attained by any but very exceptional groups. " They would represent the ideal young AngloSaxon as 6 feet high and weighing 1 1I to 12 stones." Any one of our race failing to reach this standard would be considered by the author as having been stunted by environmental conditions. He adduces in support the measurements of the rowing members of Oxford and Cambridge University boat crews. But surely a race is viewed as a congeries of genes, each of which, in respect to a character such as height, has its own maximum standard of attainment, and there must be innumerable Anglo-Saxon strains in which a height falling short of 6 feet by several inches is normal and not dependent upon environment. Do not they also serve who only sit and ' cox' ? Such criticism as this is not, however, to detract from the value of the book, but to point out the absorbing interest of the subject matter and its originality of presentment. The strong idealism of the author is shown in the tendency to stress environmental conditions. This idealism also causes him to leave the dusty road at frequent intervals in order to tilt at windmills-political, economic, and administrative. He returns, however, to the straight path after every such adventure with renewed zest and ardour. While these excursions do not advance the author's theme, they serve to make the work extraordinarily interesting to read, and to enliven a subject which might easily, by conventional presentation, have resulted in a dryas-dust disquisition.It remains to say that, as befits the subject matter of the book, the type and format are unexceptionable, the illustrations and diagrams, are numerous, and the tables clear and illuminative. While the work becomes immediately invaluable to all engaged in the problems of the care of the nation's childhood, it must remain to all time a classic.

ISSN:0028-0836    

DOI:10.1038/119269a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

AS the author says, the title of this book is non-committal, but almost unreasonably so, for in addition to most exhaustive descriptions of all the commercial varieties, this treatise contains a very complete discussion of the various scientific problems connected with the origin, breeding, and cultivation of what the daily journalist delights in describing as the " comestible tuber." Originally occupied in physiological research, Dr. Salaman has devoted the last twenty years to 'cultivating his garden' (and to some purpose), but the loss to medicine has proved a gain to agriculture. The diseases of the potato alone provide a fascinating subject for research, all the more seeing that the potato keeps up-to-date by falling a victim to virus diseases furnished with all the modern terrors of ' carriers ' and environmental 'factors.' Of these diseases Dr. Salaman says: "By directly threatening one of the most important elements of the food of the people they become a question of national concern and their investigation a matter which no country can afford to neglect "-least of all, we may add, Scotland, for the trade in Scotch seed potatoes is one of the most important that the country enjoys. We are bound to notice the author's footnote. " The Ministry of Agriculture has devoted in all but a few hundred pounds to the elucidation of a disease the ravages of which are costing the country at least five millions annually."These insidious diseases, we learn, are known popularly by such names as 'curl,' "crinkle,' "mosaic' --epithets descriptive of characteristic appearances on the foliage. Their effect is to cause a progressive deterioration in yield, amounting, in the second year of infection, to 50 per cent. and more. Scotland, it appears, particularly north of the Grampians, enjoys a considerable immunity. The reason assigned is of much scientific interest. The guilty virus is ordinarily carried from one plant to another by insects-aphides are probably the worst offenders, and in the cool climate of the north of Great Britain ' green fly' is rarely found. Seed potatoes brought from Scotland may, consequently, be free from the disease. We have said ' may,' for Dr. Salaman has proved that the infection may be 'carried,' just as that of diphtheria and other human diseases may be. It is still unsettled in what degree the superiority of the Scotch seed potato is due to this tolerance, or to absolute freedom from the disease. Dr. Salaman does not go so far as some and state that the degeneration which attacks the tuber in the south is solely due to virus diseases: in his view it is still possible that there may be an environmental or physiological cause (such as immaturity) for the superiority of northern seed. There are many other unsolved problems, most of which our author notices; a bibliography of 177 items is evidence that he has cast his net widely. When Dr. Salaman originally attacked the potato scientifically (under the inspiration, we believe, of the late Dr. Bateson) it was in the hope that the newly born science of genetics would give him useful results. It is somewhat sad to find the following passage under the heading of " The Application of Genetics to Variety Raising ": " were we, however, to possess all the data we could desire we might still be wanting in the possession of that one essential gift, the eye of the fancier, the flair of the breeder. . . . Some of the best varieties have resulted from seed secured by impregnating some favourite but nameless variety with pollen recovered from several plants mixed together on the thumb nail before being applied to the expectant stigma." That is not the only discouraging feature to the geneticist. The potato, in common with so many varieties of cultivated fruits and vegetables in Britain, is genetically 'heterozygous,' and when 'pure lined' is likely to suffer a great loss of vigour. So much is this proving to be the case that it is doubtful whetherexcept in relation to plants which are normally homnogamic, such as the cereals-the pure line will prove of much economic value.Dr. Salaman is a thorough-paced Mendelian. To the presence of multiple genes he would attribute all the varying economic characteristics of the plant -yield, shape, cooking quality, and so forth. Of all the farm crops, none is more sensitive to environmental conditions such as soil, climate, and cultural treatment. Added to these there is the admitted variability due to the degree of infection by virus disease. On the figures adduced by the author, subject as they must be to these errors, it is permissible to question the existence of genuine segregation: the facts, such as they are, might be equally well explained on the unfashionable hypotheses of blended characters, or inheritance of acquired characters. The book is produced in the style which distinguishes all the publications of the Cambridge Press, and it certainly constitutes the best textbook extant on the scientific problems of potatobreeding. As such, it should prove a welcome addition to the library of the scientific worker and, especially in regard to varieties, to that of the enlightened agriculturist.

ISSN:0028-0836    

DOI:10.1038/119271a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THE publication of Sir William Bragg's lectures to a ' juvenile auditory ' at Christmas 1925 will enable a much larger audience than could be accommodated in the historic Albemarle Street theatre to enjoy what he has to say on the application of modern scientific discovery to the study of practical problems. Our earliest inventors are known only by their works, but just as it is one of the aims of the archeologist to inform us of the social habits of past races, so the scientific investigator finds it worth while to attempt to explain the technique used in age-long industries. By so doing he not only shows us the why and wherefore of processes evolved by centuries of patient groping and accidental discoveries, but also at the same time lays bare the fundamental principles on which future improvements depend. Through the ages men have gradually learnt to smelt, cast, forge, harden, temper, spin, weave, dye, fashion, fire, and glaze, producing utensils, implements, tools, weapons, garments, and ornaments, but never before has it been possible to unfold the laws on which such operations depend for their success. The lectures cover wide and interesting fields of human endeavour, ranging from the study of the work of those who go down to the sea in ships to that done in peaceful cottages where wool and flax were spun into yarn by hand, and again to the hazardous business of mining, in which water, gas, and dust worked such havoc. In nothing has science wrought a greater revolution than in sea transport. To a seaman of the days of Elizabeth, the speed, regularity, and certainty with which passengers and goods are carried overseas to-day might well appear magical. Even in 1741, as we are told, Anson, after rounding Cape Horn, was ten degrees out in his reckoning. But with the coming of the sextant, the chronometer, and the Nautical Almanac, the mariner could fix his position with ease. Never was a nation's money more profitably spent than when IFlamsteed was made Astronomer Royal at £100 a year, or Harrison given the £20,000 for his years of labour on the chronometer. To the compass and the sextant have now been added the gyro-compass, wireless time signals, wireless direction finding, leader cables, echo sounding, and even microphones placed on the bottom of the sea far from land. With such appliances collisions are avoided, channels navigated, and harbours entered even in fog.While improvements in navigation have been mainly due to science, the progress in textile manufacturing owes most to the work of mechanical inventors. Kay's flying shuttle, Hargreaves' spinning jenny, Arkwright's water frame, Crompton's mule, and Cartwright's power loom were all designed to replace hand labour by mechanical appliances, and no one could wish for a clearer description of the processes involved than that given in the lecture on the weaver. To these inventors might have been added Eli Whitney, whose cotton gin made many fortunes, but riveted the fetters of slavery and led to civil war. In the textile industry, however, are many problems for research, and to these Sir William Bragg referred. In mining, too, it was the practical inventions of Savery, Newcomen, and Watt which made deeper mines possible, but it has been the study of scientific principles which has rendered coal-mining a hundred times safer. It is in the lectures on metals, clays, and dyes that the reader will see how the whole armoury of modern science is brought to bear on apparently simple yet really difficult problems. Chemical analysis, X-ray examination, the microscope, the theory of electrons, atoms, and molecules and internal structure are all used in the attack, and each lecture provides evidence of the value of research to industry. To the ordinary observer nothing could look less crystalline than the clay on the potter's wheel, yet even in the finest clays composed of the finest particles there is a crystalline structure, but " unfortunately, the information, while quite conclusive on this point, is not easy to interpret because our knowledge of the new X-ray methods is only in its first stages, and some problems are too hard for us as yet." As it is with the work of the potter so it is with that of the dyer and the smith, and familiar operations carried out daily in villages all over the world are subjects for the highest studies. It is to be regretted that no such lectures as these are delivered to our working men, for after reading them it is easy to agree with the remark of J. A. Froude, who, addressing the students of St. Andrews, said " that every honest occupation to which a man sets his hand would raise him into a philosopher if he mastered all the knowledge that belonged to his craft

ISSN:0028-0836    

DOI:10.1038/119272a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THE old apologetic for religion used to treat Tit, and its evidences, as if it were a branch of natural or historical science. Its truth depended on the accuracy of its cosmogony, the historicity of its mythology, and so on. All this is now recognised to be beside the point. Science and religion are regarded as two complementary methods by which different aspects of reality can be apprehended. Any satisfactory correlation of science and religion must supply a theory of the mutual relations of these two methods of approaching reality. So far as men of science are concerned, they may be said of recent years to have examined their own methods and subject matter pretty thoroughly. On the side of religion, too, a good deal has been done by philosophers such as Prof. Hbffding, Prof. Alexander, and others. But we still await the promulgation of a satisfactory philosophy of religion by a theologian. The book before us makes a genuine and sincere attempt to supply this want. Canon Streeter approaches the problem by first drawing a contrast between science and art. Between these two there are differences not only of method but also of subject matter. To take the latter point first; whereas science is concerned with the quantitative, or metrical, aspects of existence, art is concerned with its qualitative, or non-metrical, aspects. As regards method, there are two important differences: (1) Science states definitely, while art suggests; and (2) science explains observed data by bringing individual cases under a general law, whereas art reveals an inner spirit by embodying it in a concrete instance.These contrasts between the methods and material of science and art serve to illuminate the contrasts between science and religion. Religion, like art and unlike science, is concerned with the non-metrical or qualitative aspects of the world, though it is with ethical rather than with aesthetic values that it deals. With regard to method, religion, like art, suggests rather than states; and, again like art, religion isolates some individual event or circumstance, and makes it symbolic of the whole of reality, or of some dominant aspect of reality. Canon Streeter holds strongly that not only science, but also art and religion, reveal to us genuine aspects of reality, though they are different aspects. The contrast between science and religion may be expressed by saying that " what science gives us is a Representation of Ultimate Reality, and that this Representation is one that may be likened not so much to a picture as to a diagram." Whereas " what religion gives is also a Representation of Ultimate Reality, but one that is of the nature not of a diagram but of a picture." So that science and religion each give a representation which without the other is incomplete. One is like the ground-plan of Venice in Baedeker's guide, the other like Turner's famous picture, " Sunrise in Venice." These are complementary, though more or less incommensurable.Science, then, supplies us with abstract diagrams, whereas religion, using the methods of art (myth, drama, parable, hymn, etc.), presents us with the qualitative aspects of reality by making us feel these " beyond the limits of our own experience." Hence, to test the 'truth ' of any particular religion, its myths, etc., must be cross-examined. These, rather than the intellectual constructions of its theologians, indicate the spirit of a religion. No doubt, the question of the ' objectivity ' of the ' values ' of a religion is, in the end, a philosophical question. Religion cannot dispense with philosophy, or even with science, which contributes data for philosophical constructions, but philosophy is always secondary. Canon Streeter himself is far from avoiding the philosophical issue. He applies the tests indicated above to Christianity. He inquires the meaning of the Christian 'myth ' (which, however, he regards as history), and then proceeds to ask whether the values enshrined or symbolised in the myth are actually inherent in reality. He discovers that they are. He reaches this conclusion, not by the a priori reasonings by which theologians are accustomed to reach favourable results, but through a survey of scientific facts, largely from the biological sciences. Consequently, students of science will be able to follow this portion of the argument with patience, a thing they may often find difficult in this class of book. But in classing this volume with apologetic literature in general, we should not be acting fairly to Canon Streeter. It is a work of a very different type; one which all earnest students of the natural sciences would do well to read.

ISSN:0028-0836    

DOI:10.1038/119273a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THis volume fully maintains the reputation the previous members of the series have earned for the editor and publishers. The newest item in it is a description by Mr. Fishenden of the Pantone process, which Mr. Ronald Trist has now so far perfected that he no longer objects to publication of its details. " Planished plates of suitable metal are first coated with an electro deposit of copper to a thickness of, say, five one-thousandths of an inch, and then with a chromium deposit of two ten-thousandths of an inch." The plate is coated with a solution of fish-glue and bichromate, exposed, washed, and burned-in as usual in photoengraving. It is then treated with hydrochloric acid, which dissolves the chromium where it is exposed, but as it does not attack the underlying copper it cannot etch too deeply. The plate is next dipped into a solution of a silver salt, and then a few drops of mercury are rubbed over it. Amalgamation takes place immediately except in those parts where the chromium surface remains, and the mercury surface repels the ink without the use of water. The plate is now ready for trimming and mounting. The advantages of the process are many. It saves much time, as underlaying, reproving, and fine etching are unnecessary Fresh plates can be prepared as rapidly and cheaply as electros. Chromium " is five times harder than steel," and a plate that has been printed from every day for months shows by microscopical examination that each chromium topped dot retains its original perfection. An impression from a Pantone block made with a 175 to the inch screen printed simultaneously with type on a rough surfaced paper shows how perfect the dot formation is. The editor gives his usual summary of the year's progress, in which he points out the great advances being made in rotogravure colour printing now that the process is thoroughly practical, and at the end of the volume adds his " Note Book," dealing chiefly and critically with apparatus. " The Work of the Private Presses, VI., Essex House Press, 1898-1909," is treated of by Mr. Chas. T. Jacobi,with examples. A new system of music printing, " The Isotonic Notation," which is claimed to be simpler to learn as well as simpler to print than the usual notation, is described by Dom John Stephan. There are other articles of technical interest and importance, besides the usual batch of illustrations to demonstrate the present degree of perfection to which the modern reproductive processes have attained.

ISSN:0028-0836    

DOI:10.1038/119274b0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THOSE holding the opinion that chemical engineering is as distinct and important a study as are the other better-known branches of engineering might well point to the contents of this volume in justification of their views. There is a series of papers on industrial water supply and steam pollution, an authoritative discussion of filtration, a description of the machines used in magnetic separation, and a couple of lectures on petroleum distillation and steam jets. The latest developments in steam generation are also considered, for the volume includes a good account of the Brunler internalcombustion boiler, which employs a flame burning continuously under water, and an interesting description of the Benson generator, in which water is converted into steam without ebullition by heating it under the critical conditions of temperature and pressure. These brief references will suffice to indicate the wide range of technological interest covered during the year. Of the papers themselves, it need only be stated that their general merit testifies to the vitality of this youthful Institution.

ISSN:0028-0836    

DOI:10.1038/119275b0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

IN NATURE of Jan. 23, 1926 (vol. 117, p. 117), I gave a description of a method of determining ‘Hardness,’ in which a cone of the material to be tested was pressed against a hard surface (sapphire), and the area of the flat thus formed at the point of the cone by the application of a known force was measured, the hardness being defined as applied force÷area of flat, that is, as the greatest stress which the material can sustain.In all forms of tests in which hardness is determined by the effects of a crushing force (whether by the indentation caused by a hard ball or the flattening of a point or ridge) the stresses involved can be expressed as a volume-compressive combined with two shearing stresses, and the principal points of interest can be illustrated by a simple example. Consider a cube the edges of which are the axes x, y, z (Fig. 1), and let a compressive force F parallel to z act on the x, y faces, while the other x, z and y, z faces are free from any external force. These are the conditions for crushing and they can be satisfied by supposing that a volume compression F/3 acts on all the faces, while the shears the components of which, each equal to F/3 parallel to z and x and z and y, act to increase the pressure on the x, y faces and to neutralise that on the faces x, z and y, z. If k and n are the coefficients of volume compressibility and rigidity respectively, the result of the application of F is that the distance between the x, y faces is diminished by ' ( ) + ), while between the x, z and y, z faces the distance is increased by ' (), and the maximum value which can be given to F in Shear Shear:lume FIG. 1.-Compression. this expression may be taken as defining the hardness of the material.In all solids there are two distinct limits to the strains which they can withstand, namely, increase of volume and shearing strain. There is no known limit to the volume compression which can be borne by a solid; in fact, k increases continuously with the pressure, and hence when fracture is produced by crushing, the cause is to be found in its inability to resist shear. Whether the coexistence of volume compression with shearing stress alters the limits of strain for the latter is not known: it seems probable, however, that it does, or at any rate may, do so: but assuming for the moment that k and n are independent, the hardness of a solid is three times the force required to cause it to shear.In addition to the stresses just mentioned, reference must be made to the friction between the surface of the test piece and the harder substance by which the Shear F F Shear 3 Volue F E~xten s ob_) FlI. 2.-Extension. crushing force is applied. This effect, which depends on the coefficient of friction, differs for each material, but in general adds to the apparent 'hardness' by opposing sliding motion which occurs at the area of contact. In tensile tests the character of the stresses is inverted: volume compression is replaced by volume extension and the direction of the shear forces is reversed (Fig. 2).In such tests rupture may occur either because the substance cannot bear the requisite volume extension or the requisite shear, and the nature of the break depends on which of the limits is the greater. When the limit of volume extension is small the material may be malleable although not ductile, but if it is ductile it is necessarily also malleable. The accompanying table gives a list of 24 metallic elements arranged in order of their hardness. For TABLE OF 24 METALLIC ELEMENTS ARRANGED IN ORDER OF HARDNESS. Hardness stated in tons/square inch. 10 2 3 4 5 6 7 8 9 10 it 12 13 14 15 16 1 7 15 19 20 21 22 23 24 Metal. l Hardness. Iridium Molybdenum Tungsten Rhodium Nickel Chromium Cobalt Titanium Manganese lron Copper Aluminium Vanadium Palladium Silver Magnesium Zinc Gold Calcium Cadmium Bismuth Tin Lead Thallium 240 158 144 128 112 109 99 77 60 56 50 29 28 28 25 22 21 20 17-5 12 8 3 1-4 Remarks. I M. M. Wire. Thin plate, slaty fracture. M. Wire. M. Wire. Cast: Crystalline aggregate. M. Cast. Plate, slaty fracture. Brittle. Cast: Crystalline aggregate. M. From ingot made by Merriot process. Pure. M. Wire. M. Wire. Crystalline aggregate. Brittle. M. Wire. M. Cast. M. Cast. M. Cast, M. Cast. Crystalline aggregate. Brittle. M. Cast. Large, crystal. M. Cast. M. Cast. M. Cast. most of these the hardness is of little practical importance, but the table does show how capricious this quality is and how apparently unrelated either to density, atomic weight, or position in the periodic classification.Much depends on the condition of each specimen and on the treatment to which it has been subjected, as, for example, whether it is cast, forged, rolled, or drawn. In the cast state some of the metals consist of an aggregate of small crystals which separate comparatively easily, and in these cases the value found for their hardness relates to the junctions of the crystals and not to the crystals themselves. Only those metals which are, to some extent at least, malleable, give a true measure of hardness in this form of test. (These are marked M in the table.) The others show the apparent hardness of the particular specimen used, depending, in part, on the closeness of the aggregation of small crystals, or on the relation of the crystallographic axes to the direction of the crushing force.Many alloys have been tested. Various kinds of steel range from 700 tons/square inch for hardened carbon steel down to 56 tons/square inch for pure iron, and it is worth while to notice that none of the reputedly hard metals such as iridium approach the former fi

ISSN:0028-0836    

DOI:10.1038/119276a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THE review in NATURE of Jan. 15 of my criticism on Mr. Wells's somewhat antiquated biology has only just been shown to me, hence the delay in my sending this letter. I will make it as brief as possible, for I am only concerned with showing that the distinguished reviewer, Sir Arthur Keith, though he has doubtless been given a few sentences from my book for purposes of quotation, has not read the book itself.(1) He says: " So adroitly does Mr. Belloc cover his verbal tracks with a smoke screen " that he cannot determine whether I am a 'fundamentalist ' or a 'Darwinian.' As a fact, I cannot conceive myself being either, but the point is that no one who had read my book could have imagined that 'Fundamentalism' was the issue. The only issue was whether natural selection were the process whereby the differentiation of species came about. (2) He says that I give 'with approbation' St. Thomas's conclusion that the creation of man was (in scholastic language) ' immediate ': that is, special and direct. Had the reviewer read my book he could never have sincerely written that. I quoted this exceptional conclusion on immediate human creation to show that St. Thomas probably thought the creation of animate beings other than man to be 'mediate' that is, evolutionary.(3) The reviewer is " forced to the conclusion " that I have never read " The Origin of Species." If he had read my book he could not possibly have been 'forced' to so foolish a conclusion. All I say in it on this matter is written in direct relevance to that work-with its only original (and erroneous) thesis of natural selection as the machinery of differentiation. (4) He says that " Mr. Belloc resuscitates this ancient misrepresentation of 'accidental' and 'single' variations," and follows the sentence up with a good deal of irrelevant abuse. Had he read my book he wouldhave found that I knowall about Darwin's retreat in this matter, and am careful to point out that it was a muddled retreat. For the mathematical argument against natural selection applies just as much to a thousand cases out of a million as to one out of a thousand.(5) He so completely misusderstands the example I take from the growth of horns that he clearly has not read the original passage but is judging from a chance sentence put before him, and even that he fails to grasp. My point-clearly stated, emphasised, reiterated-was that multiple adaptation is mathematically incompatible with the blind mechanical action of natural selection. Multiple adaptation presupposes design. The citation of the hormone as a disproof of God is wildly off my point. One might as well say that the presence of glue in a piece of woodwork disproved the presence of a carpenter. (6) I have kept to the last the most damning count in this indictment. The reviewer sets me down as owing my remarks entirely to Mivart, as having merely copied Mivart's work of more than half a century ago: implying my ignorance of all since. Had he read my book he would have seen that I quoted from authority after authority among the highest names in modern biology from the beginning of the discussion to works which appeared so recently as three years ago. I give their actual words, which prove with what increasing force the old-fashioned Darwinian theory of natural selection has been beaten down. I end by a list of no less than forty such names-I might easily have made it a hundred. No one who had read my book could possibly have missed this continued and repeated citation of authority from every side, which is the principal feature of this section.I conclude, therefore, that the reviewer has not read my book; for I hope that not even the most violent religious animosity could lead him to deliberate misrepresentation.

ISSN:0028-0836    

DOI:10.1038/119277a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature