摘要:

THE question of the action of forests on rain1fall has been debated by foresters, agriculturists, engineers, and others for a long period, the discussion probably dating back to the time at which scientific forest conservancy was first introduced. In the tropical and sub-tropical parts of the world this is not, however, the point of primary importance. The vital factor for the community at large is the determination of how far the destruction of forests in catchment areas and on the sides of hills and mountains in the drier parts of a country affects, in the first place, the level of the water in the big rivers, a matter of extreme importance when the rivers are utilised for irrigation or power works; secondly, the decrease in the local water supplies and in local precipitations upon which the cultivator is dependent; and, thirdly, erosion and avalanches, and the destruction they cause in the fertile valleys beneath. Sudden floods may also cause enormous damage to railways, towns, and so forth. In India, which was the first part of the British Empire to give consideration to this aspect of the forest question, the matter has been the subject of discussion and reports through the whole of the past century, a statement which will perhaps come as a surprise to many in Great Britain. The problem of affording protection to forests for the above causes alone is by no means new. In France and Germany special laws for the protection and extension of the forests and the protection of agricultural lands by means of the forest have long been in operation; and similar laws exist in the Italian States. So far back as 1475 the subject attracted the attention of the famous Venetian Council of X., by whom a law was passed on January 7 of that year, regulating in great detail the clearance of the forests on terra firma. The mountain forests especially were protected by judicious regulations, which were renewed from time to time down to the very year of the extinction of the old republics. Tuscany and the Pontifical Governments were equally provident.History has since shown that the wholesale destruction of forests in Spain, Italy, Sicily, Greece, and Macedonia has resulted in a great deterioration of climate over considerable tracts, due to loss of moisture, the sterilisation of the soil, and excessive erosion. Although now well known, the chief action of the forest may be stated briefly as follows: The great factor in mountainous and hilly country is the maintenance of tree growth on parts of the area. In the case of bare slopes the rain rushes rapidly down, causing erosion, only a fraction percolating into the soil, and is carried rapidly away, giving rise to spates and perhaps to serious floods, since the old channels of these streams or rivers are no longer able to carry the excess water of flood levels. A hot sun bursting out on to the slope after the rain quickly dries up the thin layer of moisture covering it. In the hotter parts of the globe subject to heavy rainstorms or monsoons the rushing water starts gullies which eventually become ravines, all surface soil is rapidly washed away, and in the course of years the hillside is eaten into, rubble and boulders being sent down to cover up valuable lands below. When the area is under trees, a portion of the rain, falling on the crowns, drips slowly down on to the layer of humus beneath and sinks into it. The larger portion, perhaps, falls direct on to the forest floor, where it is gradually absorbed in the soft covering which takes it up as a sponge. The water then percolates slowly downwards, filling up springs and underground reservoirs, and reaches the streams in a retarded manner. The flow in the latter is consequently.more even and regulated, as also the amount of water which eventually reaches the rivers. The latter can therefore be more depended upon to maintain a normal level when it is required to utilise them for irrigation or power works. The roots of trees protect the surface by holding up the soil, and thus directly prevent denudation. It is possible to give some concrete examples of the effects of the destruction of teak forests in India during the first half of last century, owing to the large demands for this timber from rapidly expanding markets.The slopes on the west coast of the Bombay Presidency were once, even in the early days of British occupation, covered with magnificent, valuable, and extensive teak forests. These have long since been cut out, some disappearing for good. The denudation of the Deccan Highlands and the Eastern Ghhts has resulted in excessive erosion and the gradual silting up of the rivers. When the Dutch, French, and English first built settlements on the Coromandel Coast, it was possible to take ships up the Godaveri and Kistna. The English port of Narasapur and the French one of Yunaon, both on the Godaveri, were once the chief ports on this coast. They can now be reached only at high tide by small native shallow-draught craft. Last year the present writer had arranged to go down the Godaveri from Sironcha, on the frontier of South Chanda (Central Provinces) and the Hyderabad State, to Rajamundri, as he wished to carry out investigations in connexion with the effects of forest denudation on this river. It was early in March, the commencement of the hot weather season only. Inquiries elicited the fact that few rafts were now going down, owing to the extensive sandbanks already drying off in the river, and that even by dugout canoe, delays from stranding on sandbanks would be inevitable. Some hundred years ago this great river was the chief artery or high road into the interior At Masulipatam, Dutch ships used to ride at anchor close up to the port, whereas at the present day even small native vessels have to anchor five miles out in the roads owing to the silting up. Between 1840 and 1850, Dr. Gibson, the first Conservator of Forests in Bombay, drew up a list of the rivers and creeks on the Malabar coast, where on arrival in those parts ships used to ride at anchor, all the creeks having silted up within the memory of men then alive. Dr. Cleghorn, who afterwards became the first Conservator of Forests in Madras, directed attention to the destruction of tropical forests at the meeting of the British Association in Edinburgh in 1850. A committee was appointed to consider this matter. Dr. Cleghorn submitted its report, which was confined to India, the only country for which information was available, at the meeting of the Association at Ipswich the following year. The report summarised the position, as then known to the few in India who had given attention to the matter, pointing to the great and uncontrolled destruction which was taking place, both at the hands of timber merchants and owing to the careless habits of the native populations, who grazed their cattle at will in the, forests and fired them every year in order to encourage the growth of new grass. The indigenous tribes in the hilly country also practiced unchecked shifting cultivation, a practice second only to the lumberer in the destruction of fine forests. Under this method, which was a common habit in Europe in olden times, a patch of good forest is felled and the material burnt in situ; coarse grains are then sown on the clearing. The cultivator then sits down and awaits the harvest. Two or three crops are taken off the area; the weeds then became too strong (as he never troubles to weed) and he moves on to a fresh area. The enormous destruction of virgin forest this practice entails, when practised for centuries, has to be seen to be credited. Yet many of the tropical and sub-tropical forests in British Colonies and Dependencies are still subject to this the most pernicious and precarious form of so-called agriculture (as also to over-grazing and firing), the administrations responsible not having yet, apparently, understood the evils which attend it. The difficulties facing these Governments in prohibiting the practice or controlling it were all experienced in India, in one form or another, and overcome. The encouragement given to the growth of tea and coffee and similar crops by British administrations in the Empire, whilst eminently praiseworthy if carried out on well-considered lines, has been productive of great harm in the past, and even the present day can scarcely be said to be free from anxiety on this score. In a report written in India in 1876 with reference to coffee planting, the following criticism is made:" The planters who come over from Ceylon are now giving a very high price for land, and the whole mischief may be effected in a very short time. It must not be supposed that coffee is at all a permanent cultivation; we have only to look at the Sampajee Ghat in Coorg, the Sispara Ghht in the Nilgiris, and parts of the Annamalais to see at once that it is very often very little better than the shifting cultivation of the natives. It pays a coffee planter to take up a tract of primeval moist forest on our mountain slopes for a few years; he gets bumper crops the third, fourth, and fifth years, but denudation of the soil and erosion goes on rapidly, and it does not pay him to keep it up many years." Two other examples may be mentioned. In Ajmere-Merwara in Rajputana, all the waste and forest land was handed over to the people by Government in 1850. The hills were rapidly denuded of timber and grazing was uncontrolled. The crops are irrigated from tanks (ponds) formed by building embankments across ravines. Some of these were very old. The rainfall is scanty and comes in heavy showers. The water, rushing down in torrents, quickly eroded the denuded hillsides, the tanks filled up with silt and debris or the embankments burst. In 1869, at the end of a two-year famine, the region was desoribed as follows: " The cattle had perished, the people had fled, large villages were entirely deserted and the country was almost depopulated." All this was due to the mistaken policy of giving to the people what they had clamoured for, the uncontrolled use of the forest lands. An even more classic example is that of the well-known Hosiarpur Ckoh in the Punjab. These hills were formerly fairly well wooded. A rapid increase in population followed the advent of British administration in 1846. The consumption of forest produce augmented, the herds of grazing cattle multiplied excessively, and complete denudation ensued. This was followed by erosion, broad stretches of sand invading the plains beneath, with the result that the arable lands of 940 once prosperous villages were covered with sand, which laid waste upwards of 70,000 acres of fertile lands. In 1900 this formerly rich district was traversed by numerous broad, parallel, sandy belts cut out of the cropbearing and fertile area.In India these matters are now well understood, and the Forest Department, supported by the Government, has control of the great forest areas. Proofs of the disadvantages and disasters following the uncontrolled wasteful utilisation of the forests in mountainous and hilly country are not therefore wanting. It is known that the same processes are at work, and the same mistakes are being made, in our Colonies. It is the habit of British administrations to work in water-tight compartments. Probably the major portion of the difficulties being experienced in different parts of the Empire have been solved, or are approaching solution, in one or other of the provinces in India. They present no new features, as some appear to think, as the above-quoted examples go to prove. The chief difficulty is that action is delayed until almost irretrievable damage has been done and then the forester is asked to reafforest the areas so denuded. This entails an enormous expenditure, great skill, with success ever hanging in the balance. Attention was directed to this subject at the meeting of the British Association in Edinburgh in 1920, when a paper dealing with the Indian forests was read. Resolutions of the same kind were also passed by the World's Forestry Congress held at Rome in May 1926. As an outcome of last year's meeting of the British Association at Oxford, the chairman of the Forestry Sub-Section, Lord Clinton, drew up for the council a brief statement dealing with the destruction of forests on hill slopes, with special reference to the tropical forests of the Empire. This memorandum has been submitted to the Secretary of State for the Colonies, by whom it is being communicated to the Colonies and Protectorates. It may be hoped, therefore, that the chief factors of destruction, namely, shifting cultivation, excessive grazing and the firing of forest lands, may receive that measure of considered control which the expert forestry services under the Colonial Office are fully capable of inaugurating if supported by the several administrations.

ISSN:0028-0836    

DOI:10.1038/119037a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THIS instalment of Biometrika presents a strong 1claim on the interest of students of physical anthropology centred in the account which Prof. Pearson gives of the " Coefficient of Racial Likeness." This is a single numerical expression designed to measure the degree of resemblance (or divergence) of two groups of mankind. While this coefficient is the chief feature of research described in these memoirs, there is a second which should not be overlooked. The latter is an expression measuring the degree of resemblance of two groups in respect of a single character. It differs consequently from the coefficient of racial likeness, which sums up evidence furnished by a number of contributory characters. Miss Hooke is responsible for the first paper, entitled "A Third Study, of the English Skull." The previous studies were made by Dr. Macdonell (Biometrika, vol. 3, p. i9i, and vol. 5, p. 86) upon human skulls found in London, the first series coming from Whitechapel, and the second from Moorfields. Both were regarded justifiably as representative of Londoners of the seventeenth century. Miss Hooke disposes of a collection of skulls from Farringdon Street, and refers them to the seventeenth century likewise. Tables of measurements supplement the descriptions, while typecontours extend the basis of comparison with other groups. The coefficients of racial likeness have been determined, and when the results of comparing the Farringdon Street groups with those from Whitechapel and from Moorfields in succession are surveyed, the conclusion is reached that " the three are very similar, but not sufficiently so to warrant the assumption that they are drawn from a single homogeneous population" (p. 102). Resemblance is discovered between the Farringdon Street skulls and certain Scottish skulls, but marked divergence from the skulls at Rothwell, Northants, measured and described by Prof. Parsons. Dr. Morant contributes the second paper, reporting his inquiry into the characters of British crania at different historical epochs. First he reviews representatives of the Long Barrow (neolithic) population, followed in succession by those of the Bronze Age, the Iron Age, and the Anglo-Saxon period of dominance. The survey of these groups includes references to the arithmetical means of the measured characters, to the coefficient of racial likeness, to the coefficient termed a' (which measures the degree of likeness in respect of any single character), to measures of variability, and to type-contours. Discussion of the conclusions is carried into the next memoir.This paper contains the observations made by Miss Hooke and Dr. Morant conjointly on the conclusions to which their researches have led them. The ascertained values of the coefficient of racial likeness are brought together impressively in Table I. One coefficient is particularly remarkable, by reason of the emphasis it lays upon resemblance. The resemblance thus emphasised is that of the Whitechapel skulls to the British Iron Age skulls. This resemblance surpasses in closeness everything else in the table. The fourth paper is by Prof. Pearson himself. He recalls the difficulty of comparing two groups of mankind when the numbers of one or both are relatively small. He points out the difficulty of summing-up on the results of comparing characters one by one. He describes steps leading to a formula capable of measuring the degree of resemblance (or divergence) of the two groups. This formula he terms the coefficient of racial likeness; and (in regard to its indications) the nearer the numerical value is to zero the more closely associated are the two groups, in the sense that they are more probably samples of the same population.Prof. Pearson has at his disposal no less than 757 coefficients of racial likeness. Their numerical values range widely, Iio of them being less than unity, while 39 are higher than 31. Prof. Pearson suggests a classification with twelve subdivisions called grades. In Grade I. are all coefficients less than unity. They denote very intimate association. At the other end of the scale is Grade XII., including all coefficients in excess of 3i, indicating very wide divergence. A boundary is fixed arbitrarily at the number 13, and this is to mark the extreme limit at which resemblance can be claimed. The series of coefficients is next reviewed; and in regard to those with high numerical values indicative of wide divergence, Prof. Pearson is able to claim that in the vast majority of the instances available the coefficient brings confirmation to conclusions formed on independent grounds. In a corresponding manner, when scrutiny is directed to the coefficients denoting very intimate association, it is difficult to find any pair of groups " which embraces two craniologically distinct races " (p. 114). Such facts ought to establish confidence in the intermediate values and indications of the coefficient. Of these values it is remarked that some are in their purport entirely novel, while others correct views held previously as to the relation of certain groups of skulls. One of the four examples illustrating these conclusions proclaims that the English skull is nearer to that of the men of the British Iron Age than to that of the Anglo-Saxons. The conclusion reached by Miss Hooke and Dr. Morant in regard to the close association of the Whitechapel series and the British Iron Age skulls has been mentioned already. Here the setting is slightly different, and the relevant coefficients are adduced in support of the conclusion which it embodies.Turning to the records, it appears that in association with the seventeenth century English (Whitechapel series) the British Iron Age skulls yield a coefficient of 038, whereas with the same English series the Anglo-Saxon skulls yield a coefficient of 2-98. At this point it is worth recalling that in 1904, when dealing with the Whitechapel and Moorfields series, Dr. Macdonell found confirmation of the suggestion made by Prof. Pearson that the Whitechapel skulls are closer to the Long Barrow British than to the Round Barrow British, Romano-British, Anglo-Saxon or " mediaval English " represented in the museums of this country. About sixteen years later, Prof. Parsons urged the claims of the Anglo-Saxon skull in this respect, against those of the Long Barrow skull. The evidence of the coefficient of racial likeness acquires a special interest in view of this difference of opinion, and the present series of memoirs provides the following data upon this subject. COEFFICIENTS OF RACIAL LIKENESS. Whitechapel and British Iron Age . o038 ± 0-20 Whitechapel and Moorfields . . 2-05 ± 0-18 Whitechapel and Anglo-Saxon . . 2-98 ± 0-19 Whitechapel and Farringdon Street . 4-15 ±0-i8 Whitechapel and Long Barrow (p. Ioo) -7-44±-I8, (or p. 55) 3-7I±O-I8The coefficient consequently places the British Iron Age skulls closest to the Whitechapel skulls. Thus it displaces both the Long Barrow skulls and the AngloSaxon skulls from the distinctive position claimed for them by their respective advocates. The data illustrate also the varying values of the coefficient resulting from the comparison of the Whitechapel series with each of the two other seventeenth-century series of Londoners. Returning now to Prof. Pearson's paper, it will be found that he discusses the influence exerted upon the value of the coefficient by the number of the skulls available in the groups compared with each other, and again by the number and also the character of theobservations employed. A plea for standardisation in these matters is also advanced by Prof. Pearson. The application of the coefficient of racial likeness to the series of British crania has been taken above as an appropriate illustration. But although the associations there indicated and their grading may be novel, they are neither impossible, nor even extremely improbable. With such reflections in mind, attention is directed to the remarkable association assigned to Mori-ori and Fuegian skulls by the corresponding coefficient. Almost equally strange is the association indicated as existing between his Mori-ori (nonMongolian) Tibeta perusal of the list of records leaves a certain impression of caprice in the manifestations of the coefficient of racial likeness. For example, in one and the same population, namely, Londoners of the seventeenth century, the coefficient may range from 1-41 to 4-85 for male skulls and from o-96 to 5-77 for female skulls, according to the characters employed and the pairs of groups compared. Again, the comparison of various pairs of Romano-British groups yields a range of the coefficient from 0-5 to I7-48. These records must needs be borne in mind and the explanations carefully weighed before the very striking values of the coefficients relating to Tibetans, Mori-ori, and Fuegians are made the basis of arguments affecting the movements of human racial types. At present, caution enjoins reliance upon the coefficient only where its numerical values are extreme (whether low or high) and its emphasis (whether laid upon resemblance or divergence) correspondingly pronounced. In the fifth paper, Dr. R. W. Reid, emeritus professor of anatomy in the University of Aberdeen, describes two skeletons from St. Magnus Cathedral, Kirkwall, Orkney. The Icelandic Sagas and the Orkneyinga Saga provide Dr. Reid with evidence that the patron saint was executed (murdered is more correct), that the executioner used an axe, that after interment for twenty years the body was enshrined over an altar in Christ's Kirk, Birsay, and that after a sojourn there and in another church, the shrine was transferred to the cathedral. From the same sources Dr. Reid has ascertained that the body of the famous Norse St. Rognvald was buried likewise in the cathedral (of which he was actually the founder).Each skeleton occupied a recess curiously excavated high up in a pillar of the choir of the cathedral. Dr. Reid comes to the conclusion that the remains from the south pillar are those of St. Magnus, and that those in the north pillar probably belonged to St. Rognvald. The osteological descriptions are accompanied by tables of measurements and by contour tracings. Dr. Reid's conclusions make as close an approach to absolute identification as can be expected in the circumstances. Although not actually brachycephalic in terms of the proper index, both skulls by reason of their width tend in that direction. This point is mentioned in view of an opinion, based on experience elsewhere, to the effect that this tendency is very frequently to be remarked in the skulls of medieval ecclesiastics.The photographs of the skull assigned to St. Magnus suggest the possibility that two kinds of mutilation, effected at different epochs, are present. It seems not impossible that a spade may have inflicted supplementary injuries now indistinguishable from those due to the executioner's axe twenty years earlier. The difficulty of the problem has long been recognised, and a discussion thereof will be found in the " Collected Scientific Papers and Addresses " of the late Prof. Rolleston (vol. I, p. 286).

ISSN:0028-0836    

DOI:10.1038/119040a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THE application of the analyses of metal objects to 1the study of archaeology, especially in connexion with the problems of the bronze age, is becoming increasingly important owing to its bearing upon questions of cultural diffusion. If, for example, it were possible to determine by analysis the origin of the copper found in the various centres of early culture in which copper did not occur or had not been mined but had to be imported, we should probably be well on the way to solving some of the more obscure questions of pre-history. The work of the committee of the British Association which is seeking the source of Sumerian copper on these lines, when completed, may be expected to indicate how far such research is likely to be of practical utility in furnishing evidence in archieological and ethnological argument. This point is not without interest in the present connexion, as Dr. Friend, whose competence as an archaeologist and metallurgist has been proved in a number of communications to the technical journals, in his " Iron in Antiquity " has not confined his attention to the study of that metal alone. He has felt it incumbent upon him to survey briefly the technological side of the stone, copper, and bronze ages, and has thus put readers who may not be archeologists in possession of the facts which are necessary to an understanding of the special problems with which primitive users of iron had to deal. Further, he refers incidentally to the arguments relating to the diffusion of culture which have been based bv Prof. Elliot Smith upon the early use of copper in Egypt. As regards the beginnings of iron, Dr. Friend is of the opinion that meteoric and not telluric iron was the form in which it was first used. The figures he quotes in reference to the amount of meteoric iron which probably was available for the use of early man appear adequate to meet the arguments of those who hold otherwise. It would have been an advantage had the primitive furnace, especially as it occurs in Africa, received a little more detailed treatment. It would then have been more clearly apparent that the process of smelting iron is one which presented no very great difficulty to primitive man. It would seem, however: that both early and primitive peoples were not fully capable of dealing with the product of the furnace. While the Vikings, for example, were able to produce satisfactorily an object of some size, such as an anchor, a thin strip of metal such as a sword, which would retain an edge and not bend, was frequently beyond their powers. The regular occurrence in sagas and legends of swords of fame each with its own special name is some measure of the difficulty the smith experienced in producing a satisfactory weapon. In its rarity it called for special commemoration. References to the ease with which the spears of African natives were bent are frequent.Dr. Friend gives some interesting details relating to the quality and character of the metal in iron objects found in pre-Roman and Roman Britain. It is noteworthy that samples of Roman iron which have been tested for corrodibility compare favourably with modern mild steel of corresponding size. Although Dr. Friend's collection of data from various sources is admittedly not exhaustive, as supplemented by his own observations and researches, it will be of very real assistance to students of archaeology. The results of the qualitative And quantitative analyses are particularly useful and frequently illuminating. All sides of the subject are covered. The author touches upon the various uses to which iron was put-for ornament or for currency as well as for implements and weapons whether it be in the prehistoric period, in early Egypt and Mesopotamia, India, China and Japan, or among primitive peoples. It may, however, be said in passing that the chapter on Africa is scarcely adequate in view of the importance of iron-working in that continent and the amount of information about it which has been collected in recent years; and more attention might well have been given to China and Japan. Dr. Friend has not omitted to mention the interesting religious beliefs and superstitions which attach to iron, the avoidance of its use for ceremonial purposes, and the attribution of a magical character to the smith. A striking example to which he might perhaps have directed attention is found in the avoidance customswhich affect the relations of the general population with the iron-working tribes who are responsible for the supply of weapons in certain parts of East Africa; while in England, in addition to Wayland the smith, we have a good example of the smithmagician in that curious folk-song of the " CoalBlack Smith." Nor does he allude to the significant variant of the 'fairy-wife' folk-tale, once current in Wales, and elsewhere, in which the wife vanishes when struck by iron.As Dr. Friend does not confine himself entirely to the subject of iron, it may not be out of place to allude to one or two points in connexion with copper. The statement is repeated that Africa, excepting Egypt, had no copper and bronze age but passed directly from stone to iron. No doubt this is true generally; but no mention is made of the vast amount of copper which has been taken from the ancient workings in Rhodesia and the Katanga. Even now in Rhodesia the natives smelt copper in primitive furnaces. What was the destination of all the copper from these early workings, which has been estimated at an enormous number of tons ? It is urgently necessary that the dumps at the ancient mines should be examined for evidence of date before they disappear in the course of the mining operations of to-day. A committee of the British Association has been appointed with the view of following up clues furnished by objects which have come into the possession of the mining companies; but whether anything can be done must depend to a great extent on the possibility of raising funds for the prosecution of inquiries on the spot. Another curious point arises in connexion with the water-clocks in the form of a perforated bronze bowl which have been found at Wookey Hole and elsewhere. Dr. Friend is of the opinion that they are a British invention, although they occur in India and Ceylon presumably at a later date. Apparently he is not aware that they occur in Algeria also. What adds to the interest of this fact, but by no means makes it easier to explain, is that there also occurs in Algeria a primitive form of lathe which is identical in form with the lathe used in the peasant cottage-industry of woodturning in Buckinghamshire.

ISSN:0028-0836    

DOI:10.1038/119042a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

ONE of the most important branches of thermodynamics as applied to chemistry is the relation of heat of reaction with chemical equilibrium data and the calculation of the effect of temperature on the equilibrium constant. The fundamental equation here is that first deduced in its present form by van 't Hoff in i884: d log.K IdT=Q/RT2,where K is the equilibrium constant, Q the heat of reaction, T the absolute temperature, and R the gas constant. The effect of temperature on Q was known previously in the relation deduced by Kirchhoff, and special cases of the above equation had been used by Horstmann, Gibbs, and others. This is a differential equation, and its integration necessarily introduces an arbitrary constant, the value of which could be found only by experiment. It is the discovery of Nernst, published in i906, and generally known as Nernst's theorem, which enables one in many cases to find the integration constant without any information as to the states of equilibrium. This is the practical aspect of the theorem, and it will be realised that it opens out important fields of application both in the laboratory and in industry. In the shape used by Nernst, the maximum work, or diminution of available energy, is correlated with the heat of reaction in a form which is a consequence of van 't Hoff's equation, but Planck has shown that the content of the theorem can also be expressed in the statement that the entropy of every pure solid substance vanishes at the absolute zero. The entropy has been related to molecular statistics by Boltmann, Gibbs, and Planck, and in this field the quantum theory has found its place. It is therefore clear that an entirely new branch of the theory of heat has been created in recent years, and it is possible to speak of the ' New Thermodynamics ' as distinguished from the classical science evolved from the work of Joule and Carnot by Lord Kelvin, Clausius, and others.The book under notice is Prof. Nernst's own version of the new theory and of the experiments which have gone so far towards its verification. It is written in the style associated with its author; there is nothing superfluous and the mathematical apparatus is kept in its proper place. The translation has conveyed the spirit as well as the content of the original extremely well, and the book is one which ought to be a welcome addition to the library of every chemist who has occasion to make use of physical-chemical methods. It must be emphasised that Nernst's theorem has important industrial applications, and that the book is one which will be found intelligible by readers who have only a moderate knowledge of mathematics. The first part of the book deals with the specific heats of solids and gases, and the experiments which showed that at very low temperatures the specific heats of solids become very small. It was this result which gave such an important confirmation to the quantum theory as applied to material systems. The theory in the case of gases is much less complete, and there is a comparative lack of experimental data in this field. In Chap. vi. the formulation of the new theorem is dealt with, in a direct and practical manner, and then follows an attempt to explain its physical basis, which is said to be contained in the law that "there cannot be any process taking place in finite dimensions by means of which a body can be cooled to the absolute zero." Important mathematical formule used in the applications of the theorem are next summarised, and then the application of the theorem to numerous cases follows in the rest of the book. Complete numerical data, curves, and references to the literature are given.Perhaps the most interesting part of the book, from the theoretical point of view, is that dealing with the calculation of the chemical constants, which, together with thermal data, are required in the applications of the theorem. It cannot be said that this branch of the subject is yet in a very advanced state, but sufficient is given to enable the reader to understand the nature of the problem to be solved.

ISSN:0028-0836    

DOI:10.1038/119043a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THE subject matter of this book consists of a course of six lectures entitled " What to Eat and Why," given, under the auspices of the People's League of Health, by a distinguished group of lecturers. In the first lecture, on " The General Principles of Diet," Prof. Leonard Hill points out the importance of diet, sunshine, and open air in the prevention of tuberculosis and rickets. Overfeeding is stressed as being the most general error, caused by the temptation of " the arts of cooking, by pastry cooks and sweet shops." " More people are probably killed off too early by intemperance in eating than by alcoholic intemperance." The food requirements of different classes of individuals are given, and the use and misuse of some of the commoner articles of diet are discussed. The second lecture, on " The Food of Mankind treated Historically and Geographically," by Sir D'Arcy Power, affords an extremely fascinating picture of the habits that have prevailed from the earliest times. The customs of the Egyptian, Grecian, and Roman Empires are compared with those of Anglo-Saxon and Norman times, showing the evolution of present day usages. The chapter draws an important lesson, showing the relationship of moderation in food to health and character.Prof. W. D. Halliburton's lecture on " Vitamins and the Diseases caused by Badly Chosen Diet " urges the importance of milk, green vegetables, and whole-meal bread. Many will endorse the lecturer's remark: " Cursed be he who removes his neighbour's landmark, and those who interfere with their neighbours' food ought to be equally banned." But Prof. Halliburton's remark that " It is the poor, whose ignorance leads them to suppose that white bread is the best and whose poverty compels them to eat the cheapest fat," is especially poignant, as we see from the previous lecture that throughout the ages the poorer classes have invariably endeavoured to follow the habits of the more well-to-do. Dr. H. Scurfield follows with the application of the points already discussed to " Infant Feeding." The figures he has to give concerning the decrease of infant mortality in Great Britain are, encouraging and compare favourably with progress made abroad. Dr. M. J. Rowlands explains the importance of " The Feeding and Breeding of Cattle in Relation to the Health of the People." It is pointed out that as vitamins are of vegetable origin, they must be liberally supplied to the cow if the milk is to be of proper quality. This is frequently overlooked, especially in winter feeding. Besides reducing the quality of the milk, the lecturer considers that neglect of these substances is the main cause of bovine tuberculosis. The last lecture, on " Food Preservation and Adulteration," by Prof. W. E. Dixon, is comforting, for he shows clearly that the addition of preservatives is unnecessary for all foods except sausages. Australia and New Zealand send butter to the United States, where added preservatives are absolutely forbidden, so they can quite easily provide us with the same quality.The whole book is extremely readable and interesting, and should be widely studied by those interested in welfare work.

ISSN:0028-0836    

DOI:10.1038/119044a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

SOME curious phenomena accompanying the splendid aurora of Oct. 15, 1926, were observed by me. On the night in question I was working as observer of international determinations of longitude at the top of a hill named Voxenaasen in the neighbourhood of Oslo (approximate altitude, 470 metres). I was at work in a field observatory with a transit instrument registering star transits and chronometer beats for time determinations, when an initial aurora attracted my attention. My assistant was Mr. G. Jelstrup, electrotechnical student.I was able, during intervals between my observations of time and polar stars, to observe the aurora, which was certainly one of the most splendid I had ever seen. But what is of preponderant interest is the following fact: When, with my assistant, at 19h 15m Greenwich Civil Time, I went out of the observatory to observe the aurora, the latter seemed to be at its maximum: Yellow-green and fan-shaped, it undulated above, from zenith downwards-and at the 8ame time both of us noticed a very curious faint whistling sound distinctly undulatory, which seemed to follow exactly the vibrations of the aurora. The sound was first noticed by me, and upon asking my assistant if he could hear anything, he answered that he noticed a curious increasing and decreasing whistling sound. We heard the sound during the ten minutes we were able to stay outside the observatory, before continuing our observations. From 20h lm to 20h 6m (Greenwich Civil Time) we registered on our radio-receiving set the rhythmic time-signals from the LY station (Bordeaux). We secured the whole series of tops-but at the same time the 'aurora statics' disturbed the pen of the registering instrument. The impulses thus registered are of varying strength, and each of them is of course exceptionally well determined in time, being 'received' at the same time as the scientific time signals. I therefore think that they may be of some interest. The maximum impulses of 'aurora statics' and their duration were:No. Greenwich Civil Time. 1 . . . 20h 4m 28s860 2 . . . 20h 4m 298.49 3 . . . 20h 4m 39s-90 4 . . . 20h 4m 408*50 Duration. 0808 08.10 Os25 09-25 As regards the intensity of these impulses, I find that in each case the vertical component was greater than 100 microvolt/metre.When, after the reception of the time signals, we again went out of the observatory, the curious sound had absolutely ceased, and later in the night, when also the aurora had vanished, we noticed that the atmosphere was as if swept clean from statics and disturbances of our wave-length. Concerning the curious sound, I would only remark that the weather was absolutely calm when it was heard. As regards our antennme system, it may be said that it consists of 5 strands of 40 metres each. Our receiver set is an aggregate, consisting of a three-circuits tuner, two high-frequency valves, one modulator, one heterodyne, four low-frequency valves, relay and chronograph.

ISSN:0028-0836    

DOI:10.1038/119045a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

I Do not think the writer of the very full review published in NATURE (Nov. 27) of my book, “Wealth, Virtual Wealth and Debt,” really understands my new theory of money or the solution of the economic paradox, which he states, surely rather prematurely and prophetically, will be rejected by every student of economics. After all, I suppose every student of chemistry rejected the theory of atomic disintegration when it was first proposed a quarter of a century ago.The reviewer quotes me to the effect that the aggregate of money, irrespective of its quantity, represents the aggregate value of the wealth which the community prefers to be owed rather than to own-which negative quantity of wealth I term the Virtual Wealth of the community-and then states that the argument is not lucid, even to the trained student, especially when he reads on a later page that the virtual wealth has in fact little to do with the quantity of money. He alleges I do not seem to realise that people retain money balances for their convenience, although on p. 205 I state, " It suits some of the people's convenience and affairs all of the time and all of the people's some of the time to be owed rather than to possess wealth so that they may be at liberty to select at their own time the sort and quantity they need . . . in exchange for their money." Similarly, with regard to my proposals to issue national money in lieu of bank credit, ending with: " In truth, Prof. Soddy's real plea is for the nationalisation of banking," the criticism is a travesty of what I do propose and the 'real plea' about the last thing I would advocate. As regards the new theory of money, it follows the ordinary quantity theory, familiar to every trained student, in regarding the value or purchasing power of the unit of money as being inversely proportional to the quantity in circulation, considered as a single independent variable. This is the same thing as saying, as I do, that the value of all of it is the same, whatever that all may be. I should have rather expected from the trained student and the economist the criticism that my new theory was a mere round-about and unnecessary re-enunciation of the old quantity theory, though they are in fact quite different. On my theory the value of the aggregate quantity of money is a negative nonexistent quantity of wealth, not amenable to the laws of conservation, and alterable, though not very widely, by purely psychological factors. On the quantity theory it is related, in some indefinite and unexplained way, with the quantity of goods in existence, and, by what will I think come to be regarded as a very curious blunder, also with the velocity of circulation of money, although changes in the velocity of circulation affect equally rates of production and consumption and leave the quantity of goods in existence unchanged.I can only deal in limited space with a few of the other criticisms. As regards the War inflation, I do not want " to put the clock back." The evils the country is now experiencing are the direct consequence of the attempt to put the clock back to pre-War as regards the value of money. I want for the future to stop all possibility of juggling with the value of the £ sterling as much as with that of the lb. avoirdupois. The reviewer states that my proposals would bring to the ground " the whole credit structure, with all the assistance it renders to industry." My object is absolutely to destroy the whole system of fictitious credit in which, not the lender, but the general public gives up what the borrower receives, paying the principal out of the purchasing power of the money they own, and the interest out of taxation, and to replace it by a system of genuine credit in which the lender gives up what the borrower receives. As for the " assistance " the existing system renders to industry, look around and meditate upon Cacus who dragged the oxen back into his den that it might appear he had let them out. Where else but in the so-called science of business would it be deemed unimportant who provided and gave up the money for a loan so long as it was provided? The reviewer himself answers his own doubt as to how the £M2000 of new money to replace bank credit would be issued. "The new money would unuestionably be paid into the banks," who have in future to keep pound for pound against " currentaccount " deposits." The money will continue to be, as it already is, in circulation by cheque. There is no addition to the quantity, but it is proposed to rectify the omission of the banks to pay the State for it when they issued it and put it into circulation. The 'penalisation' of holders of War Loan by the redemption of their stock is imaginary. The stock would be bought on the open market,. and if they do not want to be ' penalised ' they need not sell it.I admit my proposals do not fully solve all the problems facing Great Britain in its excessive dependence on export trade for its food, and merely claim that they would make their solution easier rather than more difficult. The reviewer misrepresents me as advocating " floods of new currency . . . [being] issued by the State par passuwith the optimism of the producer " despite the absence of foreign buyers. Money is issued pari passu with increase of production to maintain the index number, or the average level of home prices, constant, and to keep them from falling with the increase of production. Goods unwanted and for which there are no buyers would fall in price, and the goods the buyers wanted would rise in price relatively as now. It is the average price-level which is maintained con

ISSN:0028-0836    

DOI:10.1038/119046b0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

IT is always unprofitable to both author and reviewer to attempt to reconcile conflicting views by further explanation on either side. Space alone precludes a successful issue. Such differences can only be left to the arbitrament of the reader. In this case he can clearly judge on the count of lucidity. A few further points may be within the limits of his patience.Prof. Soddy's conception of " virtual wealth " is a phantasyEvery deposit in a bank is balanced by an asset, presumably of genuine value and backed by real goods or definite rights. These deposits constitute part of the aggregate quantity of money The author contends in his letter that their value is a " negative non-existent quantity of wealth." Passing by the difficulties of determining how a quantity can be non-existent or how a value (connoting the abstract) can be a quantity (connoting the concrete), let the reader note that the review agreed (with the author) that the purchasing power created by bank loans is abstracted from the community, through the consequential reduction of the general purchasing power of money. Hence, if the borrower gains (temporarily and upon his undertaking ultimately to repay it to the bank) what the community loses, and if that loss is real-as Prof. Soddy truly argues-how can the gain, which is expressed quantitatively by the deposit created by the bank loan, be non-existent ? While accepting the author's statement that the nationalisation of banking is the last thing he would advocate, the reviewer still adheres to the opinion that it would be impracticable to give the State all the credit powers of the present banking system unless it also owned and conducted that system. The State is indeed contemplated (p. 198) as replacing the banks as a lender of £2,000,000,000.Prof. Soddy urges that after the State has issued this amount of new currency, each bank when it lends in future is to give up what the borrower receives. We may start then with a simple balance sheet of: Liabilities. Capital . . . £20 A's Deposit . . 100 £120 STAGE 1. Assets. Cash . . . . £120 £120B, wishing to borrow £100, goes to the bank, which is to give up to him £100 cash. Let it do so. B spends the cash in buying, say, a house from C, and C deposits the cash in the bank. The balance sheet then appears: STAGE 2. Liabilities. Capital . . . £20 A's Deposit . . 100 C's Deposit . . 100 £220 Assets. Cash B's advance . £120 100 £220So the process goes on until the ratio of cash to deposits reaches the safe limit of 1 to x. How does this differ from the present system ? Not one whit. But Prof. Soddy will retort that he has stipulated that the bank must keep pound for pound against deposits, so that stage 2 can never be reached. Exactly, and so the review stated that the banks can earn no interest, and that the whole credit structure would thereby be brought to the ground. Lastly, does Prof. Soddy seriously consider that holdings of £2,000,000,000 of interest-bearing War Loan could be permanently cancelled by its purchase on the open market in exchange for 'new national money' issued by the State, such money bearing no interest at all ? If so, he has yet much to learn of human nature.[No further correspondence on this subject can be accepted.-

ISSN:0028-0836    

DOI:10.1038/119047a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

IN his letter in NATURE of October 23, Prof. N. G. Ball throws doubts upon the validity of my conclusions that in Mimosa (1) the transpiration-current has nothing to do with the conduction of the excitatory impulse, and (2) that the conduction is a phenomenon of propagation of protoplasmic excitation. I would refer Prof. Ball to my work “The Nervous Mechanism of Plants” (1926) for accounts of experimental demonstrations fully justifying the above conclusions. Limited space available allows me to refer here only to a few of the more important results.The possibility of stimulating Mimosa by application of extracts of the stem to the basal end of a cut shoot has been adduced as evidence in support of the transpiration-current theory. This is by no means conclusive, as I have already pointed out in "The Nervous Mechanism of Plants," p. 17: " It is conceivable that certain vegetable extracts might act as stimulants; vegetable alkaloids of a poisonous nature, for example, produce excitation when applied in minute doses to the cut end of the stem. It would, however, be quite unreasonable to conclude from the result that an alkaloid is excreted from the plant under the action of a minimally effective stimulus." The following facts will be found to discredit the theory of transpiration-current. 1. The transpiration-current theory is based on the supposition that injury to wood caused by the wound, produces a stimulating substance which, being carried by the transpiration-current to the leaf, stimulates it to movement. It follows from this theory (a) that an intense wound-stimulus is essential for stimulation; (b) that the impulse should only travel upwards in the same direction as the ascent of sap; (c) that the velocity of the transpiration-current should be the same as that of the excitatory impulse; and (d) that in conditions where there can be no ascent of sap there should be no transmission of impulse.I will take these points one by one. (a) I have shown that Mimosa can be excited by an electric shock one-tenth of the intensity of that which evokes human sensation. No wound is produced, yet the excitation produced by such an excessively feeble stimulus is transmitted to a considerable distance. (b) The excitation is found to be simultaneously conducted both upwards and downwards. It is also found that, under moderate unilateral stimulation, the transmitted excitation ascends along one side of the stem to the apex and descends down the other. The transpirationcurrent could not possibly have produced this result. (c) Accurate determinations of the velocities show that the rate of transmission of excitation is several hundred times quicker than that of the ascent of sap. (d) The tip of the uppermost leaf of Mimosa was stimulated by the application of a drop of hydrochloric acid: an impulse was generated which travelled to a considerable distance downwards against the direction of the normal ascent of sap. Subsequent chemical examination proved that the stimulant had not been transported, but had remained localised at the point of application. These experimental results leave no doubt of the unfounded character of the transpiration-current theory. Nor can this theory be considered to have established its claim to acceptance until it has been demonstrated that excitation induced not by flame alone, but by stimulus of every kind-chemical, mechanical, electrical-is transmitted across the water-gap in the fundamental experiment upon which the theory has been built.2. I next adduce positive evidence which proves that the transmission in the plant is one of protoplasmic excitation. This is demonstrated by the fact that the transmission is correspondingly modified by all conditions which modify the transmission of excitation in the animal nerve. The polar action of a constant electric current is identical in the two cases; when the current is feeble, stimulation occurs at cathodemake, the excitation being transmitted to a distance; with stronger current, excitation is produced at cathode-make and at anode-break. In both Mimosa and animal nerve, the velocity of transmission is increased within limits by a rise of temperature, and diminished by a fall. In both, transmission may be arrested temporarily or permanently by various physiological blocks. When the conducting tissue in the animal or plant is cooled, the speed of the impulse is slowed down, culminating in its arrest. The conducting power is temporarily arrested by a block produced by the passage of an electric current in a portion of the conducting tissue through which the impulse is being transmitted. This electrotonic block is removed on the stoppage of the current. Finally, poisonous solutions abolish the conducting power of both animal and plant. These results offer conclusive proof that the conduction in the plant is a phenomenon of propagation of protoplasmic excitation, as in the nerve of the ani

ISSN:0028-0836    

DOI:10.1038/119048a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THE sudden appearance of fatuoids, that is, forms resembling the wild oatAvena fatua, in varieties of the cultivated oatA. sativa, has for many years attracted much attention both by its genetic interest and agricultural importance. The opinion has been widely held that they originate through natural crossing betweenA. sativaandA. fatua, but in recent years they have been more generally regarded as simple loss mutations fromA. sativa. The heterozygous form, which is intermediate between the normal and the fully developed fatuoid, usually appears first, and in nearly all cases previously recorded these heterozygotes segregate normals, heterozygotes, and fatuoids in a ratio of approximately 1: 2: 1.A combined genetical and cytological study of this problem, begun early in 1924, has revealed many new and interesting features. Not only have three, or possibly four, different types of heterozygous fatuoids been discovered, thus bringing the problem closely into line with the speltoid problem of cultivated wheat, but distinctive chromosome conditions have also been found to be correlated with the genetic behaviour and with the character of the segregates in the different types. The first and most common type, giving the 1: 2: 1 ratio of normals, heterozygotes, and fatuoids, has been described in NATURE, II5, 677-678, 1925, and Scientific Agriculture, 6, 303-313, 1926. Briefly, all the segregates are of approximately equal vigour, and all have the normal number of chromosomes, namely, forty-two; but while in the normals these form twenty-one bivalents, in the heterozygotes the arrangement is frequently nineteen bivalents, one trivalent, and one univalent, and in the fatuoids it is often nineteen bivalents and one quadrivalent. The second type also gives a ratio of approximately 1: 2: 1, though the numbers so far obtained are too small to determine this exactly, but the fatuoid segregates from it are all dwarfed and partially sterile. In this case the normal segregates again have twentyone bivalent chromosomes. The heterozygotes, however, have an extra chromosome, and their complement is either twenty-one bivalents and one univalent, or twenty bivalehts and one trivalent. The dwarf fatuoids in this type have two extra chromosomes, the total of forty-four being arranged usually as twenty bivalents and one quadrivalent. Normals and heterozygotes are segregated in approximately equal numbers by heterozygous fatuoids of the third type. The fully developed fatuoid form appears only very rarely, and is always dwarf and sterile. The normal segregates, again, have the normal twenty-one bivalents. The heterozygotes, however, have lost one chromosome and have only nineteen bivalents and one univalent. The sterile dwarf fatuoids have completely irregular meiotic divisions, including faulty pairing, and their total chromosome number is only forty.The fourth type has arisen from the third, and is similar to it except that the heterozygous segregates are much more numerous than the normals, the ratio being about 5: 1. In four heterozygous plants of this type which have been cytologically studied, the chromosome number is forty-one, as in heterozygotes of the third type. Certain differences in the chromosome behaviour, such as the more frequent formation of trivalents and the lagging of one or two bivalents, have been observed, but until the genetical constitution of the particular plants has been determined, it is impossible to say whether these minor differences have any special significance. The close correlation between cytological conditions and genetic behaviour in these different types of fatuoids seems to indicate clearly that fatuoids arise from normal oats, not by either gene mutation or natural crossing, but by any one of several different chromosomal irregularities, which upset the normal chromosome balance and permit the expression of other characters.Discussion of the particular hypothesis which best fits the observations must be left for the full account of this work, which will shortly be prepared. On the practical agricultural side there has emerged the possibility of developing commercially valuable varieties of oats which are entirely free from fatuoid factors.

ISSN:0028-0836    

DOI:10.1038/119049a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature