摘要:

A DISTINGUISHING, if not the chief, merit -£j- of a periodic congress is thff opportunity afforded for taking stock and" ^rtQ*ing progress of development, pmijpiJ^y'fVneii the terms of reference connote appMRifi Icience. / B^gn*^ /^liberations produce nothing sfartlingljCijew, as/is/of ten the case, the inevitable corrMat 19*1 of independent lines of reasoning and research serves as a stimulant to the delegate mind and creates a wider perspective, at the same time tightening the grip on essentials. This in turn has its natural repercussion amongst the greater body of workers, and thus is the spirit of technology constantly enlivened. Petroleum is a case in point. Its consideration at the second (triennial) Empire Mining and Metallurgical Congress, judged from the papers now available, is largely recapitulatory, but there is clearly apparent the aim at such co-ordination of data as may lead to some solution of the thorny problem of Imperial mineral oil resources and future supplies. The setting for such a discussion, Canada, is singularly appropriate, though paradoxical: while it emphasises the truly Imperial aspect of the question, it throws into sharp relief the unfavourable position of that great Dominion, the contribution of which is less than 0-02 per cent, of the world's petroleum production; like Great Britain, Canada is dependent on foreign sources of supply for her needs.The problem resolves itself into a dispassionate survey of hard facts: the maximum quantity of petroleum won from truly Empire sources lies between two and three million tons per annum; these limits constitute a reasonable estimate for the future. On the other hand, the total consumption of petroleum products in the Empire amounts to between ten and eleven million tons per annum, and is likely to increase considerably with each successive year. Thus Empire resources are hopelessly inadequate even for present needs. There follows the natural question: What exactly are our Imperial petroleum resources, both actual and potential, and to what extent is the British Empire committed to foreign oil supplies in the future? Failing a satisfactory solution in the shape of technical guarantees, what is the alternative to the existing situation? In substance these questions are not new; they have been raised a hundred times both on the platform and in print; they have been answered in diverse ways, but always with strong individual bias. The optimistic predictions of undeveloped oil-pools, shale-oil prospects, coal and liquid fuel substitutes, and similar panaceas variously prescribed to meet ultimate contingencies, are well known. In the light of present knowledge, such unbounded optimism is premature. At the moment the circle of argument, like that of the origin of petroleum, is still intensely vicious, but there are signs that this second Congress may be destined at last to break it.To clear the ground, a distinction must be drawn between truly Imperial oil resources and those, though developed by Imperial interests, situated in extra-Imperial territory; this is a point usually overlooked, but it is all-important to the present issue. Thus in the first category are placed India (with Burma and Assam), Trinidad, Sarawak, Egypt, and Canada; expansion is probable in the first three, extremely doubtful in the two remaining countries; to the same list may be added potential resources of New Guinea and North Borneo. Much is heard of the untapped oil reserves of the main continent of Africa, also Australia and New Zealand; unfortunately, the wish fathers the thought. Technically, the evidence tends to discount the discovery in these lands of major oil-pools destined to weigh heavily in the scheme of things; the great red spaces on the map of the world which depict Imperial terrain, lie. with one exception, tantalisingly outside the girdle of prolific oil production. Imperial petroleum interests in foreign countries are highly ramified and are of supreme economic and political import; they embrace Mexico, Persia, Venezuela, Peru, Argentine, Colombia, Rumania, and Galicia, among others. Russia is a problem unto itself, with oil as with politics; the march of time may determine the resumption of international competition for her undeveloped resources, with British interests reasserted, but prophecy concerning this unhappy country is dangerous. 'Iraq fascinates by its yet unproven possibilities, as also other regions of south-west Asia; Empire commitments here are much entangled with foreign policies, perhaps not disadvantageous in the long run. But the crucial point to remember is this: these countries constitute resources to the Empire only so long as political relationship is stable and international com rnerce is untrammelled by inimical legislation or actuality of war. Admittedly it is hard to imagine the extreme circumstance in which all these channels of supply would be blocked, especially in the light of experience gained during the War, but there is danger in the position as it stands, which would be intensified a hundred-fold if, for any reason, American sources were made unavailable for Imperial markets.The predominating position of the United States in the economics of world-supply and consumption of petroleum products has been defined so often as to be common knowledge; further statement is therefore superfluous here. To-day the Empire's dependence on that country for oil is as great as ever, for increased consumption more than balances increased production from extra-American sources. So long as one country is responsible for more than 70 per cent. (80 per cent, if Mexico is included) of the total annual output of a vital commodity, so long must it be the keystone of the whole economic structure, national and foreign, on which the relevant industry is reared. The free distribution of American oil supplies to Empire markets can only be disturbed by two eventualities: curtailment of exports to conserve national resources, or declaration of war. The first is feasible, in fact ultimately probable; the second is unthinkable, at least to the present generation. In any event, the fact that Imperial resources are totally insufficient to meet present necessities, much less any possible emergency arising from diminished trans-Atlantic supplies, serves only too well to indicate the real state of affairs. Moreover, in no other part of the world is it possible to predict, with confidence based on all available knowledge, the existence of undiscovered petroliferous territory of the magnitude and persistence of that possessed by the United States; geological work all over the world, though the detail of remote regions may still be lacking, is at least sufficiently comprehensive to justify that assertion. Thus hopes of independence of foreign sources of oil production vanish quickly when the situation is carefully examined. In the course of his address to the Congress, Sir Thomas Holland stated the case succinctly: " Under normal conditions we must depend on outside sources for a seriously large part of our petroleum products; " and again, "It is important to remember that in case of temporary isolation, even the Empire sources of crude oil may not be accessible. In any event, they would be quite insufficient even if they were available to the full. ..." It is quite impossible to encourage the slightest hope that the consumption - factor of eleven million tons or more of petroleum products per annum within the Empire can ever be attained by the utilisation of indigenous supplies. Thus technical guarantees fail and we are thrown back on alternative remedies.Sir Thomas Holland invited the Congress to consider six points which we may summarise as follows: (1) Prospects of maintaining or extending Empire production of crude oil, (2) the extent to which oil-shale exploitation may supplement mineral oil supplies, (3) prospects of obtaining oil from low temperature carbonisation, (4) possibilities of oil substitutes obtained by processes similar to hydrogenation of coal, (5) prospects of alternative liquid fuel, e.g. alcohol, and (6) increased production of light oils by cracking processes etc.The value of these headings lies in the fact that, as set out, they take nothing for granted; they presuppose no immediate remedy to be applied the moment emergency arises; they sponsor no premature optimism. The merit of the discussion along such lines lies in getting at the root of the whole matter; it is tantamount to saying, " Let us get clear for the moment from mere experimental data, from small-scale ideas which have scarcely transgressed the academic border-line. What are the large-scale possibilities of these alternatives? Which are, and which are not, of commercial application, from which a definite solution of the problem can alone spring? " Prof. Nash's paper on " Possible Auxiliary Sources of Liquid Fuels " should do much to focus attention on the true perspective of this subject; he is impressed with the many technical difficulties to be overcome before substituted fuels can compete with petroleum products, especially at current prices. The problem thus debated is bound to open out along the right lines. Economic policy and military security of the Empire demand some tangible solution to the fuel question in the near future. It is useless to leave things to chance; it is unworthy to allocate the task to posterity. The suggestion has been made that standing committees should be formed in each Dominion to watch commercial petroleum developments, to inspire technical activities, and to translate results in terms of Imperial requirements. Nothing should be allowed to hamper the fruition of any scheme to this end. Organised research, conceived and executed on a large scale, or at least with the view of commercial requirements, should receive all the backing from the governments concerned that it is possible to give; the need for this was proclaimed loudly at Wembley in 1924; it is clear that the second Congress has vigorously affirmed this demand; it is to be fervently hoped that its efforts will not be in vain.

ISSN:0028-0836    

DOI:10.1038/120429a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THE world to-day suUTO^lKpss/ipon explosions: it moves and/haer^ts very being, in the air and on the roads, Trfion and under the waters, through the agency of flame. The publication of a book dealing comprehensively with a subject of such public importance, by a master-worker, is therefore most opportune. It is so well-written that it should rank as a ' best-seller ' with Ludwig's " Napoleon " and gruesome " Jew Suss," being as readable and exciting as a " Greenmantle " or a Mason ' shocker ': though unfortunately the situations opened up are usually left unsettled and mayhap, even when ' continued in our next,' will still remain problematical. The plot, in fact, is seemingly one of fearful complexity and the detectives engaged in unravelling the story have been far from possessed of the logical training and mental agility needed to dissect out its many threads: still, that definite pathways are being cleared through the maze cannot be doubted. The book is most happily dedicated, by the authors, to Prof. H. B. Dixon, of Manchester, whose school is responsible for the greater part of the English work which is described. The issue he raised in 1880, while but a reader in Oxford, in showing that carbonic oxide was rendered incombustible even by moderate drying, underlies the whole narrative and remains unsettled to the end. It seems to be a Snark that cannot be caught-pursue it as we may and rouse it even with the high potentials the electrician of to-day has placed at our disposal, not merely with jam and judicious advice, this last being perhaps the least acceptable to its non-conformist nature. Carbonic oxide is the most elusive customer we have in chemistry.Facing the title page, the authors most appropriately quote the passage from Carlyle's " Hero as Divinity," one of the most characteristic of his essays, ending with the words, " From us too no Chemistry, if it had not Stupidity to help it, would hide that Flame is a wonder. What is Flame? " They carefully withhold the answer but, reading between their lines, we can see fairly clearly what a wondrous amount of stupidity has been displayed in seeking one: in fact, a large part of the book is a veritable comedy of errors. A deal of sack with very little bread. A wealth of experimental skill is displayed but backed by a parlous deficiency of acute theoretic dissection, Our science and our music seern indeed to be in similar quandary and but muddle through. Concertos are not concerted. Players are not playing their parts in the orchestra with effect, because of the lack of common rehearsals and the absence of skilled conductors. Verily is chemistry, at present, nought but an empiric art. We cannot be too grateful, therefore, to the'authors for having set forth the evidence so clearly. If not all, they have put most of their cards upon the table and thereby challenged us to play them: it is for us to take as many tricks as we can and they must not squeal if we are found to hold the trumps: frankly, their hand is a rotten one, their theory worse than threadbare.The purpose of the book is a review of the principal inquiries into the phenomena of combustion, from the time of Robert Boyle onwards to the present day, more particularly those of the period dating from about 1880, when Mallard and Le Chatelier and Berthelot and Vielle, in .France, began the study of explosive combustion and were followed, in England, by H. B. Dixon, Smithells, Lewes, Dugald Clerk, Bone and his pupils and others. As the principal landmark iri the survey is Dixon's theatrical discovery, over which we are still disputing, the period may well be spoken of as the carbonic oxide period. Of the five sections into which the work is divided, the first is introductory and historical, a brief but interesting survey of the work done mainly before 1880; in this, of course, Davy's and Buiisen's primary contributions are specially considered. The subjects discussed in the remaining four sections are: II. The Initiation and Development of Flame and Detonation in Gaseous Explosions (chaps. viii. to xviii.).III. Gaseous Explosions in Closed Vessels (chaps. xix. to xxiii.). IV. The Mechanism of Gaseous Combustion (chaps. xxiv. to xxxiii.).V. Catalytic and Incandescent Surface Combustion (chaps, xxxiv. to xxxvi.). The work is profusely illustrated and contains a number of very beautiful photographs, showing the propagation of explosive waves, reproduced from Prof. Bone's communications in the Proceedings of the Royal Society. For the first time, ail opportunity is given of appreciating the inventive skill and ability of the workers of the school which he has so happily called into being at South Kensington.If we are ever to acquire merit by securing ' theoretic command ' of the internal combustion engine, we must understand the so-called mechanism of combustion-hitherto, our treatment of the subject has been soulless. The authors deal with it at length but perfunctorily, particularly in discussing the combustion of carbonic oxide and of hydrocarbons. It is my fate to figure as the villain in the piece. First, under carbonic oxide (p. 337), as follows: " H. E. Armstrong, who always contends that chemical interactions cannot occur between two perfectly pure substances but require an electrolyte to form a ' closed conducting circuit,' supposed that the presence of steam, which he regards as being rendered conducting by association with some traces of an electrolytic impurity, provides the necessary conditions for the passage of the current, the oxygen playing the part of depolariser, as follows:After H20 H.O C0a CO2 CO CO O O Before OH2 OH," According to this view, the molecules of oxygen and a combustible gas are in all circumstances absolutely inert towards each other. Indeed, quite recently, Armstrong declared carbon monoxide to be 'per se an incombustible gas,' adding that ' an explanation 'may be found in the assumption that when a moist airbon monoxide mixture is sparked or fired some hydrone is decomposed and sufficient hydroyen set free to act in a depolarising circuit together with the oxide, as thus: H HO ... H 0 Hx| + + +>0:C>KHO H, \ I +>0: C) HO HO/ / H HO ... H O HO/HOH r/HO HOH=HOH O:C H0.0/ +CO," This is perhaps the most elaborate and extreme form which any chemical explanation has hitherto taken, although all of them involve the assumption that in the combustion of carbonic oxide steam is continuously decomposed and regenerated." Again, under hydrocarbons:" Another alternative, namely, that the initial stage of the oxidation of a hydrocarbon might conceivably involve the transient formation of an unstable ' oxygenated ' molecule, which, according to circumstances, would decompose more or less rapidly under the influence of heat, giving rise to simpler ' intermediate ' products, had been suggested by H. E. Armstrong but never explored experimentally. For on p. 417 of a new edition of Miller's ' Organic Chemistry,' published in 1880, he had visualised such oxidation processes as primarily involving ' hydroxylation.' In our next two chapters, we shall see how this idea ultimately furnished a solution of the problem." The issue to-day, as the authors recognise, is whether water be essential to the process of combustion.On this first count I am said to come out badly, because I have ' ignored ' " that there are well established cases (cyanogen, carbon bisulphide) in which apparently [I like the caveat and take it as evidence of a latent, uneasy conscience in the writers]combustion does not depend upon the presence of moisture." Also, because "any chemical view postulating that carbonic oxide cannot be burnt in flames except by the intervention of steam, which is continually decomposed and regenerated in the process, is countered by the spectroscopic evidence." One might use Mantalini language about spectroscopic evidence. I will only say: it leaves me cold; mercury, for example, as is well known, may be present in relatively large amount in a vacuum tube and yet be neither seen nor heard in the spectrum of the discharge. Carbon bisulphide is probably one of the liquids that is impossibly difficult to dry. The cyanogen used may even have been Bone-dry but no proof has been given that it was free from hydrogen cyanide. Go to, friend Bone, your ' well-established cases' may well go hang. " Nay, an thou'lt mouth,I'll rant as well as thou." You, in your turn, ignore the prime fact, that the heat of combustion of carbonic oxide is below that of hydrogen; also-as shown by Grove-that carbonic oxide cannot be substituted for hydrogen, in the gas cell. It cannot, therefore, be oxidised by steam.These are two nasty little facts which rather spoil your speculation: it hasn't the ghost of a theory about it. Your Bone-dry gas, after all, was not yet dry. Drying is an equilibrium process: some moisture will have been left upon the surfaces enveloping the gases. A vast amount of ' punch ' has to be put into the discharge to get it through- and yet combustion is far from complete. What happens when and as the discharge gets through? Is it not almost certain that hydrogen, imprisoned in the platinum electrodes and also platinum motes, are extruded into the gas? The photographs show that the explosive wave only ' gets up steam ' gradually. As combustion is set up less and less readily as drying proceeds, drying being never complete, is it logical to assume that another second process comes into play towards the end rather than that that initially in operation is dying out? The efficiency of your supposedly ' dry' process is so low, moreover, that the idea is not worth even provisional protection. No Comptroller could or would pass such a claim to an invention. " Tempted by extremes,The soul is most secure: Too vivid loveliness blinds with its beamsAnd eyes turned inwards perceive the lure." " Who seeks the shadow to the substance sinneth."The fact is, we have reached the limit to which experimental inquiry into such an issue can legitimately be carried. We need to sit down and calmly and logically worry out all consequences of the observations on record: to call a construction-holiday-even engage Lord Cecil to ' disarm ' our laboratories for a time and force workers to put on thinking-caps. We are in danger of making a fetish of laboratory work-the more since literary men have assumed control of the funds devoted to inquiry. The experimenter is apt to think too much of himself-to suffer from Cephalitis enlargica. He puts in his thumb and pulling out a plum thinks that he has, therefore, the right to say: ' What a good boy am I.' More often than not, he is a bad boy: the plum is a poor thing, unripe and sour; such plums should never have been made into a pie. This is particularly true in the field of biological inquiry. To experiment usefully, the motive of the experiment must be first visualised and must be logically conceived: its purpose must be clear and it must be carried through and the results punctiliously recorded and judicially interpreted with logical precision. These several ingredients are rarely present and mixed in due proportion in the research pie, nor is sufficient experience and intelligence imported into the operations. The true art of scientific inquiry is the outcome of genius and acquired only by the few: no attempt is made to teach it, in any considered way. We have to change all this, beginning in the schools. We shall do well to stay experimenting for a time and call in competent accountants-if there be such-to take stock for us and balance our books. We may then realise how ragged a state our business is in and how necessary it is to reorganise it. Our subject is very much in the condition of certain large firms that have recently lapsed into inefficiency through incompetent management. We shall certainly find that much of our stock is worthless and need to scrap a lot. We shall be in a position to say what new stock is most needed. What is good of that we have will make a brave show, when displayed apart from the rubbish with which it is now mixed. The book under notice shows this but also a lot of tares mixed with the wheat. Let us frankly admit that much of the work that is attempted to-day is too difficult for those who undertake it:" For, although common Snarks do no manner of harm, Yet I feel it my duty to say,Some are Boojums " Passing to the second count, on which I win, as the authors magnanimously admit, I have a bone to pick with them on the ground of historical accuracy: 1 am an older sinner than they suggest. If they will turn to the first edition of my " Organic Chemistry" (Longmans), published in 1874, they will find on p. 216, under Aldehydes, a statement that these are probably formed from alcohols as the result of two distinct changes, the first being " the production of a compound of the form R' . CH(OH)(OH), which is subsequently broken up into the aldehyde and water, the former of these changes being brought about either (a) by the direct addition of oxygen to the alcohol or (b) by the combined influence of the nascent oxygen and water or (c) perhaps by the agency of hydroxyl (hydric peroxide (OH)2) itself, thus:(a) R' . CH2(OH) +0=R'. CH(OH)2 (b) R'. CHS(OH) + 0 + OH2 =R'. CH(OH)2 + OH2(c) R'.CH2(OH)+(OH).,=R'.CH(OH)2 + OH2 R' . CH(OH)2-R' .-COH + OH2." I applied the ' hydroxylation ' explanation throughout the rest of the book and, afterwards, in rewriting Miller's " Organic Chemistry," published in 1880. I may add that I began the study of flame in March 1867, when I first attended a course at the Royal Institution and heard Frankland's lectures on coal gas, in which he disputed Davy's explanation of the luminosity of flames.The "never explored experimentally" in the quotation before given has an ungenerous twang. In framing my doctrine, I had before me the whole of the evidence bearing upon the ' hydroxylation ' process accumulated up to that time: it was considerable. The work done by Prof. Bone and his fellow workers is of value and importance, as showing the character and course of the changes under these or those particular conditions: not as special evidence of ' hydroxylation.' Drugman's observation, a most important one, that ethylic alcohol may be obtained directly from ethane with the aid of ozone, is the only direct demonstration to be derived from the inquiry, in justification of the view I have long held and advocated, that oxidation, in the first instance, invariably involves hydroxylation. The intensity of my belief is due to the firmness with which I hold the faith, that every chemical interaction is electrolytic in its origin and in its course and that the interactions in the Grove gas cell are to be taken as prototypical of all combustions. They are summarised in the expression:H HO ... H O H,O ... HO H H HO. HO O H2OThe authors have yet to learn that " faint love never won fair lady." They are not ' real sports.' If they were they would not hedge by saying of the " hydroxylation theory, advanced more than twenty years ago" (sic, 1880-1927=47, alternatively 1874-1927=53): " It should, however, not be interpreted or applied too rigidly, because doubtless in the long run the steady accumulation of new facts will necessitate some modifications and it would be unphilosophical to regard it as more than a serviceable tool for accomplishing further advances. It certainly affords what we believe to be a true explanation of slow combustion."The authors have their doubts as to its application to flame. The fact is, they have not yet learnt how to apply it. Their oxidation schemes are but skeleton forms - the intimate process is not considered. They visualise Oie/rmal changes as intermediate operations. Formaldehyde is figured as just breaking down into hydrogeti and carbonic oxide: CH2O=CO+H2. My sheet anchor has always been the belief in the superior charm first exercised by the oxygen atom and I would picture the downfall of forrnaldehydrol as a complex process, involving both hydroxylation and hydrolysis, at least in part often ending as shown schematically by the expression:.OH H2C(OH)2 +2(OH) =HHC(OH)(OH) = 2H2O + [C(OII)a=CO + OH2)]. Carbonic oxide, in like manner, is the product of the hydrolysis of chloroform by caustic soda. If the CH2 hydrogen were displaced by hydroxyl, formic and carbonic acids would be the products. In this instance, in my opinion, the hydrogen is quietly ' pulled away ' by hydroxyl. The production of carbon from acetylene as well as that of hydrogen from formaldehyde, are also complex, not ' purely thermal ' effects, I am satisfied.At the close of 1891, the late Sir George Stokes did me the honour to criticise an address of mine. to the Junior Engineering Society. We discussed together the interactions occurring in flames. One of my points was that purely thermal changes were unlikely to occur. My attitude was then as conservative as my ignorance was great but all that has happened in the interval of thirty-five years justifies the final plea in my letter (Chemical Society's Proceedings, 1892, 22-27): " Regarding the interactions in flames as consisting in a series of simultaneous and consecutive explosions, of which we can only examine the final steady state, it seems to me that the phenomena are necessarily of an excessively complex character and that their appreciation and successful interpretation must tax our powers of mental analysis in a very high degree. It will certainly be unwise at present to infer that the oxidation of the hydrocarbons or the separation of carbon and also of hydrogen from them, takes place entirely in any one way."The number of successive interactions involved in an oil engine explosion is almost incalculable, yet there can be little doubt as to their general course. It is impossible here, however, to discuss the subject at the length that would be necessary. The one point I desire to make is, that we not only need accurate experiment but also acute criticism of the results - what we get is worthy only of the nursery, not of the Senate House. The book under review will have failed in its mission if it have not as result a searching examination of its many propositions

ISSN:0028-0836    

DOI:10.1038/120431a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

(1) BOOKS about the relation between science and religion are apt to be heavy, but this reproach certainly cannot be levelled against Prof. Millikan's little volume. He gives in a few brilliant pages a sketch of the remarkable change which has come over the modern physical interpretation of the universe. He has been well placed to observe this change, having been, as he tells us, in direct touch with the older masters of the classical physics and having watched step by step and participated in the revolution which was initiated by Rontgen's discovery of the X-rays. He attended Rontgen's first demonstration on Christmas Eve, 1895: "As I listened and as the world listened, we all began to see that the nineteenth century physicists had taken themselves a little too seriously, that we had not come quite as near sounding the depths of the universe, even in the matter of fundamental physical principles, as we thought we had " (p. 10). This gives the key-note of Prof. Millikan's book, and most of it is a commentary, well documented, on the dangers of dogmatism both in science and in religion. His remarks about the shortcomings of the classical materialistic conception of the universe are amazingly frank. " We can still look," he writes, " with a sense of wonder and mystery and reverence upon the fundamental elements of the physical world as they have been partially revealed to us in this century. The childish mechanical conceptions of the nineteenth century are now grotesquely inadequate " (p. 27). Prof. Millikan has all the enthusiasm of the experimentalist, looking to the continued advance of experimental science for the future progress of humanity. He has a firm belief in progress as " the most sublime, the most stimulating conception that has ever entered human thought "; one respects the belief and its stimulating power, even though it may be, as he admits, an illusion, but one cannot help thinking that if progress be merely " the increasing control over environment," something else is required to make human life fuller, more adequate, and happier.Prof. Millikan's third lecture on " The Evolution of Religion " is scarcely so good as the other two -those entitled " The Evolution of Twentieth-century Physics " and " New Truth and Old "- but English readers will note with interest his view of the Scopes trial. While recognising the menace to freedom of thought implied in fundamentalism, he is inclined to think that the Scopes trial has done more good than harm, by ventilating the problems and making people think. With Prof. Millikan's conclusions, as summarised in the following passage, few, we imagine, will disagree." Physics," he writes, " has at the present moment something to teach to both philosophy and religion, namely, the lesson of not taking itself too seriously, not imagining that the human mind yet understands, or has made more than the barest beginning to ward under standing the universe. To-day physics is much more open-minded, much less dogmatic, much less disposed to make allinclusive generalisations, and to imagine that it is dealing with ultimate verities, than it was twenty-five years ago. This generalising farther than the observed facts warrant, this tendency to assume that our finite minds have at any time attained to a complete understanding even of the basis of the physical universe, this sort of blunder has been made over and over and over again in all periods of the world's history and in all domains of thought. It has been the chief sin of philosophy, the gravest error of religion, and the worst stupidity of science -this assumption of unpossessed knowledge, this dogmatic assertiveness, sometimes positive, sometimes negative, about matters concerning which we have no knowledge. ... If there is anything that is calculated to impart an attitude of humility, to keep one receptive of new truth and conscious of the limitations of our understanding, it is a bit of familiarity with the growth of modern physics " (pp. 93-4). (2) The same lesson is taught by Sir Oliver Lodge in his Hallcy Stewart lectures. He also emphasises the great significance for all branches of thought of the revolution in physical concepts which the " younger heretics" enthusiastically support. Everything has been put into the melting-pot, and the creed of science is being reconstituted. With it all, Sir Oliver pleads for a return to simplicity in matters of everyday conduct and experience, to the common-sense view of life, in accepting which the wayfaring man, though a, fool, does not err. His lectures, which cover a wide field of practical philosophy, are, we need scarcely say, distinguished by that genius for simplicity of exposition which make, them so understandable of, and so useful to, the man in the street. He emphasises, as does Millikan, the danger of dogmatism in any form and the need for freedom and fluidity of belief.Ultimate philosophy is to some extent a matter of personal conviction and experience; for this reason we do not propose to comment upon Sir Oliver Lodge's acutely dualistic scheme of things further than to express the contrary opinion that a more satisfactory philosophy is contained in the ' organic ' view of reality put forward with such skill by Prof. Whitchead.

ISSN:0028-0836    

DOI:10.1038/120435a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THE concept that the author sets out to develop is that "the soil is not the dead, inert, and simple thing often referred to as ' dirt.' It essentially a factory where raw materials are converted into finished products." In other words, the soil must now be regarded as dynamic rather than static, as indeed a living thing having complicated functional activities that react on one another and affect its productive power in the growth of plants, As a logical result, the man who understands his soil and treats it with sympathetic consideration of its individual peculiarities is in a position to get far heavier crops than he who fails to appreciate the possibility of this co-operation between soil and man. It now seems probable that the soil has a regenerative power that will enable it to produce crops indefinitely, subject to the application of knowledge and skill in its working, instead of being liable to become worked out and exhausted unless a supply of plant food elements, such as phosphorus and potash, is returned in amount equivalent to that removed by the crops. An attempt is made to draw an analogy between the soil and the animal, in view of the concept of the soil as a living entity. The various soil types are illustrated by accounts of the important soils of the United States, indications being given of the crops that are best adapted in each case, with the reasons for this association. A proper balance is necessary between what are termed the respiratory, circulating, and digestive systems of the soil for any particular crop to succeed. Methods of soil control are not confined to the replacement of plant food abstracted by crops, but include the proper rotation and adaptation of crops, suitable methods of cultivation, irrigation and drainage, and adequate balancing of organic and chemical manures. After discussion of the conception of the role of manures in ancient and modern agriculture, Whitney claims that the time has come to drop the term " plant food " as applied to fertilisers, and pleads for the recognition of the significance of the biochemical factors of the digestive system of the soil and the interdependence and the correlation which exist for the best effort of the soil, the plant, and the fertiliser treatment. In the earlier days of agriculture the responsibility for the maintenance of productivity in the fields rested entirely on the man, but even nowadays chemical fertilisers are not a substitute for human endeavour; they are simply a means of aiding to maintain agriculture in an economic position.In the cycle of ages, most civilised countries have developed well - organised agricultural systems, many of which have since died out. The cause of this often lay in a change in the character of the people, a substitution of nomadic for sedentary races, as in Asia Minor and Mesopotamia. Engineering works and irrigation systems were essential for the life of agriculture, and failure to maintain these was often the result of political changes, as in Spain after the conquest. In countries where agriculture has survived, no wars of extermination have occurred. China and Japan have maintained the productivity of their soil by sheer hard work, whereas in Egypt the natural irrigation and increased fertility due to the Nile cannot be destroyed. The agricultural literature of the Romans shows that though the soil was never very productive, intelligence was brought^, to bear upon cultivation with profitable results. The first 1500 years of the Christian era represent the Dark Ages, during which constant warfare precluded agricultural development. After Jethro Tull's advent in 1701 a gradual improvement set in in England, as well as in France and Germany. Present - day agricultural practice has not advanced greatly over that of the ancients, but more knowledge of material things has been acquired in the last century, as of steam, electricity, chemical elements, etc., and a beginning made in their application. It remains to be seen how the new discoveries will be used. There is every reason to believe we have made only a beginning in the possibilities of research, and it is not outside the bounds of possibility that improvement in important farm crops, as wheat, corn, oats, cotton, may yet be made more commensurate with the development already achieved in animals, in orchard fruits and garden vegetables, by means of intelligent application of the principles of science to agriculture.

ISSN:0028-0836    

DOI:10.1038/120436a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THE publication of Sir Charles Sherrington's -L " Integrative Action of the Nervous System " marked the beginning of a new epoch in neurology. Until then attention had been centred mainly on the analysis of the central nervous system into its anatomical components, the fibre tracts, and nuclei. Their different functions were investigated but very little was known of the way in which these functions were carried out. Sherrington used an entirely different method, the analysis of the complex behaviour of the organism into its component reflexes. Taking the reflex as the basic reaction of the central nervous system, he showed how the reflexes are compounded and adjusted to make up the changing pattern of activity which we see in the organism in its natural surroundings. The analysis of the activity of the central nervous system into the constituent reflexes is and must remain for a long time the most potent method of neurological research; but it was clear that the analysis could be pushed a stage further, for the reflex itself is not an irreducible unit but is made up of a complex of activities in the nerve fibres, synapses, and muscles. Not long after Sherrington's book had focussed attention on the reflex, Keith Lucas began an attempt to work up to the reflex from the unit reactions of the nerve fibre. This work was cut short by the aeroplane accident which deprived physiology of one of its most powerful investigators, but its influence has been far-reaching, and in recent years there has been an increasing tendency to analyse the reflex into the simple reactions of muscle and nerve along the lines which Lucas suggested. This tendency is reflected in the present book, which is written by a pupil of Sherrington's on the basis of work carried out at Oxford during the past four years.To some extent Dr. Fulton works at a disadvantage, in that there is no very clear, picture to present. Much work is still in progress on the physiology of the muscular contraction and of the nervous impulse, and although we can see a good way into the processes involved in the activity of the nerve and muscle fibres, we are still in the stage of collecting information and modifying our hypotheses to suit each new piece of evidence. For this reason there is much that is bound to be speculative in Dr. Fulton's presentation of the facts of muscle and nerve physiology, as, for example, in his discussion of the latent period, the summation of contractions, the neuro-muscular junction, etc. There is still more uncertainty when we come to build up a picture of reflex activity out of what is known of the simpler reactions of nerve and muscle. We are still in the throes of a controversy (very well handled by Dr. Fulton) on the nature of the tonic contraction and the relation of the sympathetic system to it, and we have not advanced beyond the stage of multiple hypotheses on the subject of central inhibition. But for all that, the position is clearing rapidly. We know what goes into the central nervous system and what comes out of it, the messages from the sense organs and the messages to the muscles. In every case the message consists of a series of nervous impulses of the type made familiar by investigations on the isolated nerve fibre, and the recent work in Oxford has done much to suggest how the incoming and the outgoing messages are related to one another in the central nervous system. Although the time is scarcely ripe for the presentation of a complete survey of reflex activity, Dr. Fulton is certainly to be congratulated on the orderly and readable account he has made, both of his own researches and of the great mass of recent work on the many fields involved. Any one who is concerned with the physiology of movement, whether as an investigator, a teacher, or an examinee, will find this book a most valuable (though expensive) collection of recently acquired facts and theories. There is an interesting historical introduction which does not omit due reference to Aristotle, and the book is closed by a table of more than 1000 references. In these days it is hard to overestimate the value of a comprehensive review of this kind, and Dr. Jfulton deserves high praise for writing it.

ISSN:0028-0836    

DOI:10.1038/120437a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THE author of this entertaining and beautifully illustrated book did not live to see its publication, but he has left behind him a record of picturesque experience and eloquent enthusiasm. Dr. Lee's work lay largely amongst the extravagant scenery of the western of the United States; while in later years he assisted in the exploration of the great Carlsbad Cavern, and began the study of landscapes from the air. The book reflects a corresponding love for the colourful and spectacular, and in an informal and non-technical way it succeeds in imparting not only the romantic spirit of geology but also a good deal of sound knowledge. The Grand Canyon is selected as the point of departure because it introduces rocks of the earlier eras. Other pages of earth history are written round the Painted Desert and Petrified Forest of Arizona; the high plateaux and Vermilion Cliffs of Utah; the ioe-scuptured Yosemite Valley; and the impressive peaks of the Rocky Mountain National Park. Many of the illustrations are reproductions of photographs taken from 'the air, and the book as a whole is original in both manner and matter. Teachers of geography will find in it many a telling example, and though its appeal will necessarily be mainly American, it can be cordially recommended to the layman who is looking for a brightly written interpretation of landscape and earth history.

ISSN:0028-0836    

DOI:10.1038/120438b0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

A FEW nijtttj^O" tae Society Islands gave Miss CheesmajSropporlrunities of seeing Tahiti, Raiatea, and Bora Bora, and her experiences and observations are recorded in this delightful volume. It differs from most books on the South Sea Islands in describing not merely the well-populated coast regions, but also the less visited high ground of the interior. Miss Cheesman's main object was to study the insect life of the islands, which was not well known before her visit, and while insects loom large in her pages, she misses nothing of interest in natural history. The book, in fact, is a record of a naturalist's wanderings, written with considerable descriptive power and much appreciation of the beauty of the islands. It is illustrated by a few photographs and sketches by the author. Among the many books on Tahiti it deserves to take a prominent place. There are appendices which give a catalogue of the fauna.

ISSN:0028-0836    

DOI:10.1038/120439c0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THE problem of an adequate supply of the fatsoluble vitamins for the needs of the growing population has received prominent attention at the recent meeting of the British Association. The shortage in the supply of milk fat in particular was emphasised, and a simple calculation led to the conclusion that this shortage is not a local one in Great Britain, but of world-wide extent. Butter is irreplaceable by margarine as long as this article of diet is deficient in vitamins. Even if we do not share the gloomy view as to the effect of this shortage on the health of the nation, since milk fat is not their only source, it must be admitted that the problem of the supply of fatsoluble vitamins is of outstanding importance.We would like to direct attention to the outcome of recent researches, only partially published as yet, in the course of which we became aware of easily accessible sources of both vitamins A and D. The solution of the problem depends now only on the industrial application of the knowledge made available by such research, So fa,r as vitamin A is concerned, we found that the chromogen responsible for the arsenious chloride colour reaction, discovered by one of us (O. R.), is present not only in the liver of the cod, but also in the livers of all animals examined, fishes, birds, and mammals. A study of the quantitative distribution of this chromogen and its correlation with vitamin A by means of the biological growth-test (Lancet, ii. 806; 1926), proved that the amount present in other liver fats in many cases far exceeds that found in cod-livor oil, the richest source of vitamin A previously known. It must be remembered that the main reason for the selection of the cod as a source of medicinal oil, leading to the development of the cod-liver oil industry, was the extraordinarily high fat content of the cod's liver and its relatively easy extraction on a commercial scale. As regards vitamin A content, however, we found that the liver oils of other fishes, such as salmon or halibut, are often more than 100 times as rich as cod-liver oil.On account of their limited accessibility, these oils cannot be considered as a commercial source of vitamin. The same reason excludes tho liver fats of birds, some of which, such as those of the grouse, goose, fulmar petrel (Biochem. Jour., Ill; 1927), are extremely potent. The liver fats of herbivorous mammals, on the other hand, appear to be an ideal source of vitamin A. Those animals live mainly on green fodder, the original source of vitamin A, and accumulate a store of it in the liver, as do fish and birds. We found by both colorimetric and biological tests that the liver fats of sheep, calf, and ox contain on the average as much as ten times the amount of vitamin A as a good Newfoundland cod-liver oil. Taking the vitamin A content of butter-a very variable factor-as from 1/20 to 1/100 that of cod-liver oil, those fats may be said to be from 200 to 1000 times more potent in this respect than butter. A recently published letter (see Times, Sept. 7) shows that by an interesting coincidence our results in this respect are confirmed by the independent observations, hitherto not published in detail, of Prof. Wilson, formerly of Cairo. According to these, " the liver fats of Egyptian sheep and oxen appear to contain about 200 times tho amount of vitamin A found in tho best butter examined." Without entering into a calculation of the available supply of liver, we may assume that Great Britain's need is easily met at home, supplemented if necessary by Empire produce. It may be stated that the vitamin content of the fat obtained from imported New Zealand liver equalled that of the liver of home-killed animals. As an additional advantage for tho purpose suggested, we find that these fats are free from the objectional flavour of fish oils, which is apparently connected with the presence of the highly unsaturatecl clupanodonic acid (C22H34O2) and the Fearon colour reaction (Biochem. Jour., 1342; 1926). Owing to their low melting-point, liver fats can be easily incorporated with other fats, such as margarine. Although easily extracted by the use of fat solvents, their isolation would probably not be necessary in largo scale manufacture. Vitamin A, being fat-soluble, can be directly extracted from the tissue by a neutral oil. The well-known skill of the margarine manufacturer should enable him so to incorporate the liver fats with his product as to convert a dietary article, already identical with butter in calorific value, into a cheap and palatable product of equal biological efficiency, so far as vitamin A is concerned.The no less important vitamin D, another variable constituent of butter, remains to be considered. Contrary to the expectation that this would also be contained in the mammalian liver fat, we found that the liver fat of sheep, at any rate, is practically devoid of this vitamin. It would seem that, unlike fish, the herbivorous mammal does not store vitamin D in the liver. On the other hand, the body fats of certain fishes, although free from vitamin A, as tested both colorirnetrically and biologically, were found to bo a good source of vitamin D. An interesting exception to what appears to be a general rule was revealed in the examination of the body oil obtained from eels. The oil content of this fish is relatively high (about 30 per cent.), and it contains not only vitamin D, but also vitamin A in an amount nearly equal to that of some Norwegian ood-liver oils (tested colorimetrically and controlled by the animal test). This result confirms, incidentally, the high value empirically attributed to the eel as an article of diet. There is, however, no need to search any longer for a natural soTirco of vitamin D, since we are now able to produce this important vitamin artificially by irradiation of ergosterol (Biochem. Jour., 389; 1927). Irradiated ergosterol possesses extraordinarily potent anti-rachitic activity, 1/10,000-1/20,000 iiigm. per diem preventing and curing rickets in rats. Clinical experience has since shown that human rickets also is rapidly cured by daily closes of 2-4 mgm. The amount to bo incorporated with margarine need, therefore, be only extremely small. By tt study of the best conditions of its formation in yeast, a practically unlimited supply of ergosterol should be available for this purpose.The margarine manufacturers have therefore at their disposal, if they care to make use of them, means which should make a perfect biological substitute for butter accessible, without unduly raising the price of margarine. Moreover, by carefully controlled methods of manufacture, it should be possible to supply a product of constant vitamin content, superior in this respect to natural butter, the vitamin content of which depends on too many uncontrollable factors of the food supply of the cow.

ISSN:0028-0836    

DOI:10.1038/120440a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

A KNOWLEDGE of the process whereby the latent image is produced on the exposure of a photographic emulsion to light is of primary importance to those engaged in fundamental photographic research. For some years past this problem has been under investigation in the laboratories of the British Photographic Research Association, and considerable progress has recently been made in our knowledge of the primary light action.As a first step, our method has been to try to identify the photographic mechanism with some characteristic of the silver halides which can be studied by purely physical methods, in the absence of-such disturbing factors as gelatin, etc. It has been known for a long time that the silver halides possess both photo-electric and photoconductivity properties. By the former is meant the complete liberation of electrons from the salt under light action, and by the latter the freeing of electrons internally, resulting in a change of conductivity on illumination (sometimes called the internal photoelectric effect). It seemed possible to us that the mechanism responsible for one of these effects might be identified with that which produces the latent photographic image, and consequently we started more than two years ago a series of experiments to investigate thoroughly the two effects in relation to the silver halides, and especially to silver bromide.The results of a long series of experiments which were published (Phil. Mag., 3, 482; 1927) indicated that the photographic mechanism was not photoelectric in the sense of its being a complete liberation of electrons from the crystal of silver bromide. The evidence in support of this conclusion is that photographic action takes place in an emulsion made with silver bromide at wave-lengths very much longer than the longest which will produce any photo-electric emission from that salt. A detailed investigation of the second, i.e. photoconductivity effect, has now been in progress for more than a year, and the results already obtained seem to be sufficiently striking to warrant publication in the form of a preliminary note.A study of the literature indicated that in many ways a parallelism does exist between photoconductivity and photographic effects. For example, the spectral regions to which emulsions are sensitive photographically are the same on the long wavelength side as those to which the corresponding pure halides show photo-conductivity effects. Take the most important case-that of silver bromide. The photo-graphic spectral sensitivity of a slow silver bromide emulsion increases very rapidly towards the blue from practically nothing at about X5000. The very trustworthy experiments of Coblentz (U.S. Bureau of Standards, Scientific Paper No. 256) on the photoconductivity of silver bromide showed that this effect also commences in the same spectral region as the photographic effect and increases also towards the blue. To this extent, therefore, the two effects are parallel. Coblentz's results, however, showed a very serious departure from the photographic case in that as the wave-length decreased from X5000, the photo-conductivity effect (for equal energy) after rising rapidly to a maximum, fell practically^ to zero at about X4200. This, at first sight, seemed to indicate that the mechanisms producing the two effects are different, because it is well known that photographic action occurs at wave-lengths far shorter than A4200. In the case of such thickly coated plates as are , commonly used in photography, there is a,n apparent decrease of sensitivity as we pass from the violet to the ultra-violet. This effect has, however, been shown (Phil. Mag., 49, 1104; 1925) to be due, not to a real decrease in sensitivity of the grains of silver bromide, but to secondary effects involving the thickness of the sensitive film. Experiments with thinly coated plates demonstrated (Trans. Faraday Soc., 19, 290; 1923; Phil. Mag., 48, 947; 1924) that the photographic sensitivity of silver bromide actually increases on passing from the violet to the ultra-violet. It was thought that the sharp decrease of photo-conductivity in the violet and the apparent absence of the effect in the ultra-violet reported by Coblentz might also have been due to a ' thickness ' effect in the specimens used by him and was not an inherent characteristic of the silver bromide.Since the light absorption by silver bromide increases extremely rapidly with decreasing wavelength from the blue to the ultra-violet, the former light penetrates much farther than the latter into the silver bromide layer. Since, further, the electrical conductivity depends on the whole thickness of the layer, it was suspected that the relative photoconductivity effects at different wave-lengths depends on this thickness, just as we have shown the photographic effect o so to depend. Experiments were therefore undertaken to measure the photo-conductivity effects at the three wave-lengths A4385 (blue), X4060 (violet), and A3650 (ultra-violet), and to see whether their relative values varied with the thickness of the silver bromide specimen employed. Preliminary experiments have completely verified the predictions, and have shown that while with a fairly thick specimen (about 0-7 mm.) the relative order of effects is blue>violet>ultra-violet, yet as th>e thickness of the specimen is decreased, so the violet and ultra-violet increase relatively to the blue, the order given above becoming completely reversed with a sufficiently thin specimen. The thinnest yet measured is about 0-07 mm. thick, and even for this the effect of a given amount of energy is about twice as great at A3650 as at A4358. Thus what seems to have been the greatest difficulty in the way of demonstrating the identity of the photographic mechanism and that which produces a change in electrical conductivity on illumination, has been removed. There is considerable experimental evidence that the mechanism of the photo - conductivity effect observed with many crystalline metallic halides involves the loosening of electrons from the halide ions of the lattice. The present work therefore adds considerable weight to the hypothesis that latent image formation involves the transfer of valency electrons from bromide ions to silver ions, resulting in the formation of metallic silver and free bromine.

ISSN:0028-0836    

DOI:10.1038/120441a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

ONE of the points in Mr. Frankland's letter is answered by Mr. Forbes in his last paragraph, in which he enunciates a correct sylvicultural prescription that sylviculture and high farming are not dissimilar, in that the former requires at least as close a knowledge and practice; and that to curtail expense in the first years is to produce an inferior article which may prove unsaleable at a profit. Mr. Frankland's second point on the subject of the possibilities and limitations of successful forestry on the high-lying moorlands so common in Britain is not at present easily answered since practical experience is almost absent. It may, however, perhaps be stated with some confidence that the solution is unlikely to be found in wide spacing. To be successfully marketed, timber from such regions must be of as high a quality as possible. In France, where since the War exposed areas of this type are being afforested, this business is being approached from the viewpoint that close spacing is the first necessity; and that this spacing must be maintained until close canopy has been produced. Subsequent thinnings will probably be delayed owing to the slower growth to be expected; but such thinnings will be carried out as required, irrespective of whether the material is saleable or otherwise.

ISSN:0028-0836    

DOI:10.1038/120442b0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature