do with the Royal Society's Catalogue of Scientific Papers or the International Catalogue of Scientific Literature. Now two channels for the publication of scientific papers must be accepted without cavil. In each country (for international publications, however desirable, present almost insurmountable mechanical difficulties) it is well that there should be a periodical devoted to each "branch" of science, and as time goes on each "branch" will naturally become more and more subdivided. This may be regarded as the natural, and, putting on one side historical considerations, the first channel. But the publications of established academies and of the older special societies must be accepted also. The newer special societies would do well to make use of the special journals, in some such way as the Physiological Society makes use of the Journal of Physiology, and perhaps even some of the older ones might adopt the same methods. In any case, there is no reason for special comment on these two channels. But things are different when we come to consider the kind of publication of which I have given examples above. Let me take, for instance, the Journal of the Marine Biological Association, and the Thompson-Yates and Johnston Laboratories Reports. The number of the former is almost wholly occupied by a memoir of systematic zoology, the number of the latter by papers on trypanosomiasis. Why should the student in systematic zoology, who has possibly at some expense taken steps to secure ready access to the publications of the Zoological and Linnean Societies, have also to run after the Journal of the Marine Biological Association? Why should the student in tropical diseases have to run hither and thither, seeking in this and that report what he ought to find ready at hand either in the Journal of Comparative Pathology or Journal of Hygiene, or some still more special periodical? Now there can be no doubt that the causa causans of the two periodicals in question is advertisement. One cannot but sympathise with the efforts of the Marine Biological Association to make its worth known; one has also sympathy with the University of Liverpool, but less acute since its great merits are in everyone's mouth. But I venture to put the question, Is it desirable that, for the mere sake of advertisement, the progress of science should be hindered? For anything which puts obstacles in the way of the student getting ready access to a knowledge of what has been done is a distinct hindrance to progress. Why should not the Marine Biological Association spend the money which it has spent in printing the Hon. C. Eliot's valuable memoir on British nudibranchs in subsidising some acknowledged channel of zoological publication. It is well that the association should have a journal, but that journal ought to be occupied exclusively by business matters; all scientific papers of permanent value produced by help of the association ought to be published elsewhere. In the same way, why should not the Liverpool University spend some of the ample funds at its disposal in subsidising periodicals, many at least of which are in urgent need of support? This would in the end be even a better advertisement. The Lister Institute sets in this respect a very good example. It too has need of advertisement, but the results of the varied work carried on there are published each in an appropriate acknowledged channel. It limits its direct advertisement to issuing in a collected form reprints of the various papers scattered over many periodicals. re The scientific papers in Government publications stand on a somewhat different footing from those just spoken of. The Annual Report of the medical officer of the Local Government Board referred to above contains, besides several papers of direct administrative value, under the term port a number of valuable papers of a purely scientific character, papers to which every inquirer in pathology ought to have ready access. But why should a scientific library, and why especially should the limited library of a pathological institute or laboratory, for the sake of a mouthful of pure science. burden its shelves with an intolerable mass of adminis trative details? The publications of the medical oficer of the Local Government Board do not stand alone in this respect. In the enormous mass of printed matter which H.M. Government puts out every year there are hidden, buried, lost to view. records of scientific research of varying but not unfrequently of great value, records to which the scien tific inquirer ought to have ready access. This official burial of scientific work does a double harm; it harms him who did the work, it harms all those who, through the burial, miss knowing what has been done. Of course it must be recognised that H.M. Government, having ordered and supplied the funds for a scientific inquiry, has a right of possession in the records of that inquiry, so that by the official publication of that record it may justify before Parliament and the public the order for the inquiry. The matter is further complicated by the fact that when the order for inquiry is part of the work of a Royal Commission, the results of such an inquiry cannot be made known until the report of the commission on its work as a whole is laid before Parliament and published. But these difficulties are not such as cannot be overcome. A small Commission of the nature of what is known as a Departmental Committee, appointed some little time back to investigate plague in India, has, with the approval of the authorities, adopted the following plan. While making the usual arrangements for the reports on administrative matters, it proposes to publish from time to time the scientific results of the work of the commission in an appro priate scientific journal, securing, by the purchase of extra copies of the records thus published, the means for the complete publication of the whole work of the commission at some future period. Such a plan might be extended to all scientific inquiries carried out by order of H. M. Government; it needs nothing more than frank negotiations between persons responsible to H.M. Government and editors of scientific periodicals. Such a plan would bring many blessings. It would enable the man of science who is putting his best into the work which he is doing for Government to feel that the record of his work will not be hopelessly lost sight of. It would save other men of science the labour of hunting for scientific needles in Government bottles of hay, or the chagrin of finding out, when too late. that by shrinking from such uncongenial labour they had missed something of great price. It would save the nation a not inconsiderable sum of money, and yet furnish the editors of scientific journals with money, which many of them need for the conduct of their journals, and which most of them at leas! would use in helping the poor author to a more complete publication of the records of his work. Lastly. it would relieve the bibliographer from much weari some labour. In every way, in fact, it would tend to advance natural knowledge. x. THE YORK MEETING OF THE BRITISH ASSOCIATION. THE York meeting of the British Association, night, promises to be a very large one. The local arrangements and the programmes of the various sections have already been described in these columns. Among the representatives from abroad who are expected at the meeting are the following :-Section A, Prof. H. Rubens, the University, Berlin; Prof. C. G. Rockwood, Prof. F. P. Whitman. Section B, Prof. Paul Pelseneer, Ghent; M. G. Grandidier, Paris; Dr. and Mrs. Yves Delage, Paris; Prof. Looss, Cairo; Prof. Gary N. Calkins, New York; Prof. H. F. E. Jungerson, Copenhagen; Dr. Gustave Loisel, Utrecht. Section C, Prof. Edgworth David, Sydney. Section E, Prof. Loezy, Budapest. Section F, Prof. K. Wicksell, Lund. Section K, Prof. W. Johannsen, Copenhagen; Prof. C. H. Ostenfeld, Copenhagen; Dr. C. Rosenberg, Stockholm; Prof. E. Pfitzer, Heidelberg; Prof. and Mrs. Jeffrey, Harvard University; Prof. Ligrier, Caen; Prof. H. Potonie, Berlin. Corresponding member, Prof. C. Julin, Liége. The Court of the University of Leeds has resolved to confer the honorary degree of D.Sc. upon the following in connection with this meeting of the Association:-Prof. E. Ray Lankester, F.R.S.; Prof. A. Grandidier, of Paris; Prof. P. Pelseneer, of Ghent; and Prof. H. Rubens, of Berlin. The degree of D.Sc. will be conferred upon the following in connection with the meeting of the Association and also with the coal-tar colour jubilee :-Sir W. H. Perkin, Dr. Heinrich Caro, of Mannheim; Prof. Albin Haller, of Paris; Prof. C. Liebermann, of Berlin; and Dr. C. A. von Martins, of Berlin. OF THE INAUGURAL ADDRESS BY PROF. E. RAY LANKESTER, M.A., MY LORDS, LADIES AND GENTLEMEN,-It is, first of all, my privilege to thank you for the distinguished honour you have done me in electing me President of this great scientific Association-an honour which is enhanced by the fact that our meeting this year is once more held in the venerable city of York, in which seventy-five years ago the British Association for the Advancement of Science held its first meeting. It is a great pleasure to me to convey to the Lord Mayor and the dignitaries and citizens of York your hearty thanks for the invitation to meet this year in their city. It seems to have become a custom that the Association should be invited at regular intervals to assemble in the city where it took birth and to note the progress made in the objects for the furtherance of which it was founded. A quarter of a century ago we met here under the presidency of that versatile leader in public affairs-Sir John Lubbock, now Lord Avebury. That occasion was the jubilee the fiftieth anniversary of the Association. Lord Avebury on that occasion gave as his presidential address a survey of the progress of science during the fifty years of the Association's existence. He had a wonderful story to tell, and told it with a fulness which was only possible to one of his wide range of knowledge and keen interest in the various branches of science. If I venture on the present occasion to say a few words as to the great features in the progress of our knowledge of Nature during the last twenty-five years, it will be readily understood that the mere volume of new knowledge to be surveyed has become so vast that a full and detailed statement such as that which Lord Avebury placed before the Association at its jubilee is no longer possible in a single address delivered from the President's chair. Let me ask you before we go further to take for a few moments a more personal retrospect and to think of the founders of this Association, then of the great workers in science who were still alive in 1881 when last we met here and have since gone from among us, leaving their great deeds and their noble enthusiasm to inspire now and for all future time those who have vowed themselves to the advancement of science in this realm of Britain. There must be some here who had the privilege of personal acquaintance with several of the men who founded this Association in York seventy-five years ago. I myself knew Prof. John Phillips, Sir Charles Lyell, Sir Roderick Murchison, Sir David Brewster, Dr. Whewell, and Mr. Harcourt of Nuneham. All these fathers of our Association had passed away before our last meeting in York. And now, in the quarter of a century which has rolled by and brought us here again, we have lost many who took an active part in its annual meetings and were familiar figures in the scientific world of the later Victorian period. Huxley and Tyndall, Spottiswoode and Cayley, Owen and Flower, Williamson and Frankland, Falconer and Busk, Prestwich and Godwin Austen, Rolleston and Henry Smith, Stokes and Tait, and many others are in that list, including one whose name was, and is, more often heard in our discussions than any other, though he himself never was able to join us-I mean Charles Darwin. Happily some of the scientific veterans of the nineteenth century are still living, if not with us in York. Sir Joseph Hooker, who visited the Antarctic with Ross in 1839, is still hale and hearty, and so are Alfred Russel Wallace, Lord Kelvin, Sir William Huggins, and many others who were already veteran leaders in scientific investigation when last we visited York: they are still active in thought, observation, and experiment. 66 66 In attempting to give an outline of the advancement of science in the past twenty-five years I think it is necessary to distinguish two main kinds of advancement, both of which our founders had in view. Francis Bacon gave the title " Advancement of Learning to that book in which he explained not merely the methods by which the increase of knowledge was possible, but advocated the promotion of knowledge to a new and influential position in the organisation of human society. His purpose, says Dean Church, was to make knowledge really and intelligently the interest, not of the school or the study or the laboratory only, but of society at large." This is what our founders also intended by their use of the word advancement." So that in surveying the advancement of science in the past quarter of a century we of the British Association must ask not only what are the new facts discovered, the new ideas and conceptions which have come into activity, but what progress has science made in becoming really and intelligently the interest of society at large. Is there evidence that there is an increase in the influence of science on the lives of our fellow-citizens and in the great affairs of the State? Is there an increased provision for securing the progress of scientific investigation in proportion to the urgency of its need or an increased disposition to secure the employment of really competent men trained in scientific investigation for the public service? I. THE INCREASE OF KNOWLEDGE IN THE SEVERAL The boundaries of my own understanding and the practical consideration of what is appropriate to a brief address must limit my attempt to give to the general public who follow with friendly interest our proceedings some presentation of what has been going on in the workshops of science in this last quarter of a century. My point of view is essentially that of the naturalist, and in my endeavour to speak of some of the new things and new properties of things discovered in recent years I find it is impossible to give any systematic or detailed account of what has been done in each division of science. All that I can attempt is to mention some of the discoveries which have aroused my own interest and admiration. I feel, indeed, that it is necessary to ask your forbearance for my presumption in daring to speak of so many subjects in which I cannot claim to speak as an authority, but only as a younger brother full of fraternal pride and sympathy in the glorious achievements of the great experimentalists and discoverers of our day. The duty of attempting some indication of their work is placed upon me as your President, and it is for my effort to discharge that duty that I ask your generous consideration. As one might expect, the progress of the knowledge of nature (for it is to that rather than to the historical, moral and mental sciences that English-speaking people refer when they use the word "science") has consisted, in the last twenty-five years, in the amplification and fuller verification of principles and theories already accepted, and in the discovery of hitherto unknown things which either have fallen into place in the existing scheme of each science or have necessitated new views, some not very disturbing to existing general conceptions, others of a more startling and, at first sight, disconcerting character. Nevertheless I think I am justified in saying that, exciting and of entrancing interest as have been some of the discoveries of the past few years, there has been nothing to lead us to conclude that we have been on the wrong path -nothing which is really revolutionary; that is to say, nothing which cannot be accepted by an intelligible modification of previous conceptions. There is, in fact, continuity and healthy evolution in the realm of science. Whilst some onlookers have declared to the public that science is at an end, its possibilities exhausted, and but little of the hopes it raised realised, others have asserted, on the contrary, that the new discoveries such as those relating to the X-rays and to radium-are so inconsistent with previous knowledge as to shake the foundations of science, and to justify a belief in any and every absurdity of an unrestrained fancy. These two reciprocally destructive accusations are due to a class of persons who must be described as the enemies of science. Whether their attitude is due to ignorance or traditions of self-interest, such persons exist; and it is one of the objects of this Association to combat their assertions and to demonstrate, by the discoveries announced at its meetings and the consequent orderly building up of the great fabric of "natural knowledge," that Science has not come to the end of her work-has, indeed, only as yet given mankind a foretaste of what she has in store for it-that her methods and her accomplished results are sound and trustworthy, serving with perfect adaptability for the increase of true discovery and the expansion and development of those general conceptions of the processes of nature at which she aims. New Chemical Elements.-There can be no doubt that the past quarter of a century will stand out for ever in human history as that in which new chemical elements, not of an ordinary type, but possessed of truly astounding properties, were made known with extraordinary rapidity and sureness of demonstration. Interesting as the others are, it is the discovery of radio-activity and of the element radium which so far exceeds all others in importance that we may well account it a supreme privilege that it has fallen to our lot to live in the days of this discovery. No single discovery ever made by the searchers of nature even approaches that of radio-activity in respect of the novelty of the properties of matter suddenly revealed by it. A new conception of the structure of matter is necessitated and demonstrated by it, and yet, so far from being destructive and disconcerting, the new conception fits in with, grows out of, and justifies the older schemes which our previous knowledge has formulated. Before saying more of radio-activity, which is apt to eclipse in interest every other topic of discourse, I must recall to you the discovery of the five inert gaseous elements by Rayleigh and Ramsay, which belongs to the period on which we are looking back. It was found that nitrogen obtained from the atmosphere invariably differed in weight from nitrogen obtained from one of its chemical combinations; and thus the conclusion was arrived at by Rayleigh that a distinct gas is present in the atmosphere, to the extent of I per cent., which had hitherto passed for nitrogen. This gas was separated, and to it the name argon (the lazy one) was given, on account of its incapacity to combine with any other element. Subsequently this argon was found by Ramsay to be itself impure, and from it he obtained three other gaseous elements equally inert : namely neon, krypton, and xenon. These were all distinguished from one another by the spectrum, the signmanual of an element given by the light emitted in each case by the gas when in an incandescent condition. A fifth inert gaseous element was discovered by Ramsay as a constituent of certain minerals which was proved by its spectrum to be identical with an element discovered twentyfive years ago by Sir Norman Lockyer in the atmosphere of the sun, where it exists in enormous quantities. Lockyer had given the name helium to this new solar element, and Ramsay thus found it locked up in certain rare minerals in the crust of the earth. But by helium we are led back to radium, for it was found only two years ago by Ramsay and Soddy that helium is actually formed by a gaseous emanation from radium. Astounding as the statement seems, yet that is one of the many unprecedented facts which recent study has brought to light. The alchemist's dream is, if not realised, at any rate justified. One element is actually under our eyes converted into another; the element radium decays into a gas which changes into another element, namely helium. Radium, this wonder of wonders, was discovered owing to the study of the remarkable phosphorescence, as it is called the glowing without heat-of glass vacuum-tubes through which electric currents are made to pass. Crookes, Lenard, and Röntgen each played an important part in this study, showing that peculiar rays or linear streams of at least three distinct kinds are set up in such tubesrays which are themselves invisible, but have the property of making glass or other bodies which they strike glow with phosphorescent light. The celebrated Röntgen rays make ordinary glass give out a bright green light; but they pass through it, and cause phosphorescence outside in various substances, such as barium platino-cyanide, calcium tungstate, and many other such salts; they also act on a photographic plate and discharge an electrified body such as an electroscope. But the most remarkable feature about them is their power of penetrating substances opaque to ordinary light. They will pass through thin metal plates or black paper or wood, but are stopped by more or less dense material. Hence it has been possible to obtain shadow pictures" or skiagraphs by allowing the invisible Röntgen rays to pass through a limb or even a whole animal, the denser bone stopping the rays, whilst the skin, flesh, and blood let them through. They are allowed to fall (still invisible) on to a photographic plate, when a picture like an ordinary permanent photograph is obtained by their chemical action, or they may be made to exert their phosphorescence-producing power on a glass plate covered with a thin coating of a phosphorescent salt such as barium platino-cyanide, when a temporary picture in light and shade is seen. 66 The rays discovered by Röntgen were known as the X-rays, because their exact nature was unknown. Other rays studied in the electrified vacuum-tubes are known as kathode rays or radiant corpuscles, and others, again, as the Lenard rays. It occurred to M. Henri Becquerel, as he himself tells us, to inquire whether other phosphorescent bodies besides the glowing vacuum-tubes of the electrician's laboratory can emit penetrating rays like the X-rays. I say "other phosphorescent bodies, for this power of glowing without heat-of giving out, so to speak, cold light-is known to be possessed by many mineral substances. It has become familiar to the public in the form of "phosphorescent paint, which contains sulphide of calcium, a substance which shines in the dark after exposure to sunlight-that is to say, is phosphorescent. Other sulphides and the minerals fluor-spar, apatite, some gems, and, in fact, a whole list of substances have, under different conditions of treatment, this power of phosphorescence or shining in the dark without combustion or chemical change. All, however, require some special treatment, such as exposure to sunlight or heat or pressure, to elicit the phosphorescence. which is of short duration only. Many of the compounds of a somewhat uncommon metallic element, called uranium. used for giving a fine green colour to glass, are phosphorescent substances, and it was, fortunately, one of them which Henri Becquerel chose for experiment. Henri Becquerel is professor in the Jardin des Plantes of Paris: his laboratory is a delightful old-fashioned building, which had for me a special interest and sanctity when, a few years ago, I visited him there, for, a hundred years before, it was the dwelling-house of the great Cuvier. Here Henri Becquerel's father and grandfather-men renowned throughout the world for their discoveries in mineralogy, electricity, and light-bad worked, and here he had himself gone almost daily from his earliest childhood. Many an experiment bringing new knowledge on the relations of light and electricity had Henri Becquerel carried out in that quiet old-world place before the day on which, about twelve years ago, he made the experimental inquiry, Does uranium give off penetrating rays like Röntgen's rays? He wrapped a photographic plate in black paper, and on it placed and left lying there for twenty-four hours some uranium salt. He had placed a cross, cut out in thin metallic copper, under the uranium powder, so as to give some shape to The photographic print should one be produced. It was produced. Penetrating rays were given off by the uranium: the black paper was penetrated, and the form of the copper Cross was printed on a dark ground. The copper was also penetrated to some extent by the rays from the uranium, so that its image was not left actually white. Only one step more remained before Becquerel made his great discovery. It was known, as I stated just now, that sulphide of Calcium and similar substances become phosphorescent when exposed to sunlight, and lose this phosphorescence after a few hours. Becquerel thought at first that perhaps the uranium acquired its power similarly by exposure to light; but very soon, by experimenting with uranium long kept in the dark, he found that the emission of penetrating rays, giving photographic effects, was produced spontaneously. The emission of rays by this particular fragment of uranium has shown no sign of diminution since this discovery. The emission of penetrating rays by uranium was soon found to be independent of its phosphorescence. Phosphorescent bodies, as such, do not emit penetrating rays. Uranium compounds, whether phosphorescent or not, emit, and continue to emit, these penetrating rays, capable of passing through black paper and metallic copper. They do not derive this property from the action of light or any other treatment. The emission of these rays discovered by Becquerel is a new property of matter. It is called " radio-activity," and the rays are called Becquerel rays. From this discovery by Becquerel to the detection and separation of the new element radium is an easy step in thought, though one of enormous labour and difficulty in practice. Prof. Pierre Curie (whose name I cannot mention without expressing the grief with which we all heard in April last of the sad accident by which his life was taken) and his wife, Madame Sklodowski Curie, incited by Becquerel's discovery, examined the ore called pitch-blende which is worked in mines in Bohemia and is found also in Cornwall. It is the ore from which all commercial uranium is extracted. The Curies found that pitch-blende has a radio-activity four times more powerful than that of metallic uranium itself. They at once conceived the idea that the radio-activity of the uranium salts examined by Becquerel is due not to the uranium itself, but to another element present with it in variable quantities. This proved to be in part true. The refuse of the first processes by which in the manufacturer's works the uranium is extracted from its ore, pitch-blende, was found to contain four times more of the radio-active matter than does the pure uranium. By a long series of fusions, solutions, and crystallisations the Curies succeeded in hunting down," as it were, the radio-active element. The first step gave them a powder mixed with barium chloride, and having 2000 times the activity of the uranium in which Becquerel first proved the existence of the new propertyradio-activity. Then step by step they purified it to a condition 10.000 times, then to 100,000 times, and finally to the condition of a crystalline salt having 1,800,000 times the activity of Becquerel's sample of uranium. The purification could go no further, but the extraordinary minuteness of the quantity of the pure radio-active substance obtained and the amount of labour and time expended in preparing it may be judged from the fact that of one ton of the pitch-blende ore submitted to the process of purification only the hundredth of a gram-the one-seventh of a grain-remained. The amount of radium in pitch-blende is one tenmillionth per cent.; rarer than gold in sea-water. The marvel of this story and of all that follows consists largely in the skill and accuracy with which our chemists and physicists have learnt to deal with such infinitesimal quantities, and the gigantic theoretical results which are securely posed on this pin-point of substantial matter. The Curies at once determined that the minute quantity of colourless crystals they had obtained was the chloride of a new metallic element with the atomic weight 225, to which they gave the name radium. The proof that radium is an element is given by its " sign-manual "-the spectrum which it shows to the observer when in the incandescent state. It consists of six bright lines and three fainter lines in the visible part of the spectrum, and of three very intense lines in the ultra-violet (invisible) part. A very minute quantity is enough for this observation; the lines given by radium are caused by no other known element in heaven or earth. They prove its title to be entered on the roll-call of elements. The atomic weight was determined in the usual way by precipitating the chlorine in a solution of radium chloride by means of silver. None of the precious element was lost in the process, but the Curies never had enough of it to venture on any attempt to prepare pure metallic radium. This is a piece of extravagance no one has yet dared to undertake. Altogether the Curies did not have more than some four or five grains of chloride of radium to experiment with, and the total amount prepared and now in the hands of scientific men in various parts of the world probably does not amount to more than sixty grains at most. When Prof. Curie lectured on radium four years ago at the Royal Institution in London he made use of a small tube an inch long and of one-eighth inch bore, containing nearly the whole of his precious store, wrenched by such determined labour and consummate skill from tons of black shapeless pitch-blende. On his return to Paris he was one day demonstrating in his lecture room with this precious tube the properties of radium when it slipped from his hands, broke, and scattered far and wide the most precious and magical powder ever dreamed of by alchemist or artist of romance. Every scrap of dust was immediately and carefully collected, dissolved, and re-crystallised, and the disaster averted with a loss of but a minute fraction of the invaluable product. Thus, then, we have arrived at the discovery of radiumthe new element endowed in an intense form with the new property radio-activity" discovered by Becquerel. The wonder of this powder, incessantly and without loss, under any and all conditions pouring forth by virtue of its own intrinsic property powerful rays capable of penetrating opaque bodies and of exciting phosphorescence and acting on photographic plates, can perhaps be realised when we reflect that it is as marvellous as though we should dig up a stone which without external influence or change, continually poured forth light or heat, manufacturing both in itself, and not only continuing to do so without appreciable loss or change, but necessarily having always done so for countless ages whilst sunk beyond the ken of man in the bowels of the earth. Wonderful as the story is, so far it is really simple and commonplace compared with what yet remains to be told. I will only barely and abruptly state the fact that radioactivity has been discovered in other elements, some very rare, such as actinium and polonium; others more abundant and already known, such as thorium and uranium, though their radio-activity was not known until Becquerel's pioneer-discovery. It is a little strange and no doubt significant that, after all, pure uranium is found to have a radio-activity of its own and not to have been altogether usurping the rights of its infinitesimal associate. The wonders connected with radium really begin when the experimental examination of the properties of a few grains is made. What I am saying here is not a systematic, technical account of radium; so I shall venture to relate some of the story as it impresses me. Leaving aside for a moment what has been done in regard to the more precise examination of the rays emitted by radium, the following astonishing facts have been found out in regard to it: (1) If a glass tube containing radium is much handled or kept in the waistcoat pocket, it pro |