114 



NA TUBE 



[Decemeer 5, 189: 



importance and originality. His researches on the deep sea 

 deposits, and his general discussion of the oceanographic 

 results of the expedition, are recognised as being of first-rate 

 quality. ._,.,, ^ 



Dr. John Murray has already received the " Prix Cuvier of 

 the French Academic des Sciences, and it is right that the cor- 

 responding body in this country should take the first opportunity 

 available to it, after the completion of the Challenger Reports, 

 to express its appreciation oJ their value. 



Royal Medal. 



Prof. James Alfred Ewitig, F.R.S. 



A Royal Medal is conferred on Prof. J. A. Ewing for his 

 investigations on magnetic induction in iron and other metals. 



The magnetic properties of iron and steel when subjected to 

 magnetising forces of different intensities, under various con- 

 ditions of temperature and mechanical stress, have been studied 

 by many physicists both in this country and abroad. In a series 

 of papers which have appeared at intervals during the last four- 

 teen years. Prof. Ewing has put on record a remarkable 

 collection of experimental facts connected with these compli- 

 cated subjects. In some of his results and methods he was 

 anticipated by others, but apart from the wide extent of his 

 investigations, he has displayed great sagacity^ and originality 

 both in his more fundamental researches, and in the directions 

 in which he has developed his work. 



Having studied the behaviour of iron when subject to mag- 

 netic forces which vary in a cycle, he applied the same process 

 to nickel, proving that, as in the case of iron, the susceptibility 

 is constant for small forces, but that the range of force over 

 which this law holds good is much larger for nickel than for 

 iron. 



Prof. Ewing has also investigated the behaviour of iron and 

 steel of various qualities, of manganese steel, of cobalt and 

 nickel, when placed in very strong magnetic fields, the intensity 

 of which was raised to the splendid magnitude of 46,000 C.G.S. 

 units in the air around the metal bar under observation. He 

 thus showed experimentally, in corroboration and extension of 

 Joule's primary discovery, that the intensity of magnetisation 

 approaches asymptotically towards a limiting value, which it 

 very nearly reaches before the magnetising force attains a com- 

 paratively small magnitude, and at which it remains constant 

 while the magnetising force is increased without limit. 



Not content with investigations such as these. Prof. Ewing has 

 made an important advance in our knowledge of the probable 

 constitution of magnetic substances. He constructed a model 

 of such bodies by placing a number of small magnets near to 

 each other so that each is free to rotate in a horizontal plane. 

 These magnets, when disturbed, settled down into groups of more 

 or less stable equilibrium, which are gradually broken up under 

 the influence of increasing magnetic forces. This model sug- 

 gests the novel and most important conclusion that the act of 

 magnetisation is accompanied by the re-arrangement of similar 

 groups of magnetic molecules. So closely does it reproduce the 

 behaviour of iron, that it is possible not only to imitate the more 

 prominent phenomena, to copy the curve of magnetisation, and 

 the loops produced by cyclic forces, but also to detect minor 

 details which were for long overlooked in iron itself. 



Throughout these theoretical researches Prof. Ewing has paid 

 attention to their practical applications. The well-known 

 phenomenon which he has named " hysteresis " plays an im- 

 portant part in the action of transformers. He has, on this 

 account, invented two instruments by which the magnetic pro- 

 perties of samples of iron can be readily tested. 



Prof. Ewing's researches on magnetic induction are described 

 in a series of memoirs published in the Transactions of the 

 Royal Society, and in a number of shorter papers which 

 appeared chiefly in the Roy. Soc. Proc. and the " Reports of the 

 British Association." He ranks as one of the principal authori- 

 ties on a subject of great theoretical and practical importance. 

 He has thrown light upon the theory, and has facilitated its 

 application to industry. 



Davy Medai. 



Prof. William Ramsay, F.R.S, 



Prof. Ramsay's earlier researches were in the department of 



organic chemistry. Nearly twenty years ago he was carrying on 



researches on picoline and its derivatives, which were published 



KO. 1362, VOL. 53] 



in the Phil. A fag. for 1887 and 1888, and on quinine and its • 

 decomposition products, the results of which were published ia 

 the Ckem. Soc. Trans, for 1878 and 1879. 



Prof. Ramsay's later researches have been more devoted to- • 

 subjects in the borderland dividing chemistry and physics. la. • 

 1879 and 1 88 1, he published in the Chem. Soc. Trans, four 

 papers on molecular volumes, and between the years 1880 and 

 1892 he communicated to the Royal Society eight papers on the 

 critical state and properties of liquids, two being published in 

 the Proceedings, and six in the Plnl. Trans. In 1893 he pub- 

 lished the results of researches on molecular surface energy in 

 the Phil. Mag., the Chem. Soc. Trans., and \hA Proc. Roy. Soc. 

 In 1893 he communicated to the Phil. Mag. a very important 

 paper on the expansion of rarefied gases. 



But the researches on which the award of the Davy Medal to 

 Prof. Ramsay is chiefly founded are, firstly, those which he has 

 carried on, in conjunction with Lord Rayleigh, in the investi- 

 gation of the properties of argon, and in the discovery of improved 

 and rapid methods of getting it from the atmosphere ; and, 

 secondly, his discovery in certain rare minerals of a new ele- 

 mentary gas which appears to be identical with the hitherto 

 hypothetical solar element, to which Mr. Lockyer many years 

 ago gave the name of "helium." The spectrum of this terres- 

 trial gas was seen at first as an extremely narrow and sharp line 

 of a brilliant yellow colour, close to, and slightly more re- ' 

 frangible than, the sodium lines Dj and Dj, and having a wave- 

 length near to 5876, this, according to recent determinations, 

 being the wave-length of the solar line of helium, or, as it is 

 usually designated, D3. Shortly after its discovery. Prof. Runge, 

 of Hanover, announced that the yellow line of Ramsay's gas- 

 was double, consisting of a strong component having a wave- 

 length of 5875-88, and a faint component having a wave-length 

 of 5876 '2 1. As no observer had seen the solar line, D3, double 

 doubt was thrown on the first assumption that Prof. Ramsay had 

 actually isolated a solar element hitherto unknown on the earth. 

 Within the last few weeks, however. Dr. Huggins, in England, 

 and Prof. Hale, in America, have detected the presence of a 

 faint luminous companion of D3 in the spectrum of the chromo- 

 sphere, and as these solar lines have the same wave-lengths as 

 those of the corresponding terrestrial lines, the doubts at first 

 raised have been set at rest. The body giving rise to the .-.olar 

 line Dj, and Prof. Ramsay's new gas from cleveite, uraninite, 

 broggerite, monazite, and many other rare minerals, is now 

 admitted by chemists, physicists, and astronomers to be the same- 

 substance — helium. 



The conferring of the Davy Medal on Prof. Ramsay is a 

 crowning act of recognition of his work on argon and helium,, 

 which has already been recognised as worthy of honour by 

 scientific societies in other countries. For his discoveries on 

 these gases he has already been awarded the Foreign Member- 

 ship of the Societe Philosophique de Geneve, and of the Leyden 

 Philosophical Society. He has had the Barnard Medal of the 

 Columbia College awarded to him by the American Academy of 

 Sciences, and within the last few weeks he has been elected a. 

 Foreign Correspondent of the French Academic des Sciences. 



Five years have now passed since you elected me to be your 

 President. Living at a distance of 400 miles from London, I 

 felt that it could not be possible for me to accept the honour 

 when the possibility of its being offered to me was first 

 suggested. I accepted, with much misgiving as to my ability to 

 pertorm the duty which would fall upon me ; and now, after 

 having been re-elected four times, I feel that if the interests of 

 the Society have not sufi'ered under my Presidency, it is chiefly 

 because they have been so faithfully and unintermittently cared 

 for and worked for by the other officers, the Treasurer and the 

 Secretaries, who have left nothing undone that could be done to 

 promote the welfare of the Royal Society. For their unfailing 

 kindness to myself I can only offer my heartfelt thanks. I soon, 

 found that what I looked forward to with apprehension— the 

 Council meetings, and as many of the ordinary meetings as I 

 could attend, during my University session in Glasgow— were 

 the reverse of fatiguing ; and I am only sorry that I have been 

 so many times obliged to forego the pleasure of performing that 

 part of my Presidential duty. I look back otherwise with un- 

 mixed pleasure to all the meetings at which I have presided, and 

 my sole regret now is — I cannot disguise it, and it is a very keen 

 regret— that these five years are passed, and that to-day I cease 

 to be your President. I thank you all, my colleagues of the 

 Royal Society, for electing me five times to be your President, for 



