136 



NA TURE 



[December 6, 1894 





twelve years of it, a first importaot part of the object, the 

 determinalion of the atomic weight of oxygen with ail possible 

 accuracy was attained by the comparison,' of Scott's determina- 

 tion of the ratio of the volumes of hydrogen and oxygen in the 

 constitution of water, with Rayleigh's determination of the 

 ratio of the densities. The result wa> 15S2, which is almost 

 I per cent. (0S7 per cent.) less than the 16, which it 

 would be according to Prout's law. It is very slightly less 

 (I per cent.) than Dittmar and Henderson's value obtained by 

 an investigation- for which the Graham medal of the Glasgow 

 Philosophical Society was awarded in 1S90. Valu:s, not quite 

 so small as tlie-e for the atomic weight of oxygen, had been 

 previously found by Cooke and Richards (15869) and by Leduc 

 (15 876). There can be no doubt whatever now that the true 

 value is more than \ per cent, smaller than according to Trout's 

 law, and that in all probability it agrees exceedingly closely 

 with the results o!)tained by Rayleigh and Scott, and liy Dittmar 

 and Henderson. The question of Pioul's law being thus so far 

 set at rest, Rayleigh, persevering in the main object which he 

 had promised in 1SS2, "a redetermination of the densities of 

 the principal gases," attacked nitrogen resolutely and, stimulated 

 by most disturbing and unexpected difficulties in the way of 

 obtaining concordant results for the density of this gas as 

 obtained from diSferent sources, discovered that the gas obtained 

 by taking vapour of water, carbonic acid, and oxygen from 

 common air was denser-' by i 230 than nitrogen obtained 

 by chemical processes from nitric oxide or from nitrous 

 oxide, or from ammonium nitrite, thereby rendering it 

 probable that atmospheric air is a mixture of nitrogen, and a 

 small proportion of some unknown and heavier gas. Rayleigh 

 and Ramsay, who happily joined in the work at this stage, have 

 since succeeded in isolating the new gas, both by removing 

 nitrogen from common air by Cavendish's old process of passing 

 electric sparks though it, and taking away the nitrous com- 

 pounds thus produced by alkaline liquor; and by absorption 

 by metallic magnesium. Thus we have a fresh and most in- 

 teresting verification of a statement which I took occasion to 

 make in my presidential address to the British Association in 

 1871,'' " Accurate and minute measurement seems to the non- 

 scientific imagina'ion a less lofty and dignified work than look- 

 ing for something new. But nearly all the grandest discoveries 

 of science have been but the rewards of accurate measurement 

 and patient long-continued labour in the minute sifting of 

 numerical results." The investigation of the new gas is now 

 being carried on vigorously, and has already led to the wonder- 

 ful conclusion that the new gas does not combine with any 

 other chemical substance which has hitherto been presented to 

 it. We all wait wiih impatience for further results of their 

 work ; we wish success to it, and we hope that it will give us, 

 before the next anniversary meeting of the Royal Society, 

 much knowledge of the properties, both physical and chemical, 

 of the hitherto unknown and still anonymous fifth constituent of 

 our atmosphere. 



Copley Medal. 



Dr. Edward Frankland, !■'. K. S. 



The Copley Medal is awarded to Dr. E. Frankland for his 

 eminent services to theoretical and applied chemistry. 



At a time when the classification of organic compounds in 

 homologous series was a comparative novelty, when isomerism 

 was still a profound mystery, and the theory of compound 

 radicles introduced by Liebig was still on its trial, Dr. Frankland 

 made his first attempt 'in 1S48) to isolate the radicle of common 

 alcohol. Though the attempt was in one sense unsuccessful, 

 ina.<much as the free radicle was never obtained, for reasons 

 which we now more fully understand, the research led to 

 important consequences. The discovery of the organo-melallic 

 compriunds, and the study of their composition and properties, 

 wax followed by a recognition of the fact, first that the capacity 

 for combination possessed by the atoms of the metals was 

 limited (I'hil. 7'raiii., 1852), and secondly that variation of 

 "atomicity," as it was then called, usually occurs by an even 

 number ol units (yoiini. Chcm. Soc, 1866), represented by 

 alomi of hydrogen, chlorine, or such compound radicles as 

 methyl, ethyl, and the rest. These discoveries form the basis 



* Scoll, '■ On the Composition of Water by Volume." communicated by 

 Lord kayl^ie**. f^fy ^01- i'rac, March 2\. iSoj. 



2 /• ^ ' •' - '■ ' ■ -' ^ V of Glalgow, 1890-1891. 



a - '-rminalion^ of the Density of 



\itr 



* K^l' 1^ I rir J >n ■ >i ii .i t'u'ii..i ,. ...turet ftoU Addresses." 



of the modern doctrine of valency, with all the important 

 consequences that follow, including the idea of the orderly 

 linking of atoms, and hence the theories of structure or 

 constitution now current. 



The discovery of zinc ethyl placed in the htinds of chemists 

 an important new instrument of research, which Dr. Frankland 

 was himself the first to use in his investigations concerning the 

 synthetical production of acids of the lactic and acrylic series. 

 Further important synthetical work, conducted in concert with 

 Mr. Duppa, led to a method of ascending the series of acids 

 homologous with acetic acid. 



Dr. Frankland's researches in pure chemistry are almost 

 rivalled in interest by his discoveries in physical chemistry, 

 especially in relation to the influence of pressure on the rate of 

 combustion, on the light emitted during combustion, and on 

 the cause of luminosity in hydrocarbon flames. 



The important work done by Dr. Frankland in the study of 

 water supply and sewage, and illuminating gas, has proved of 

 great practical value, and has rendered his name famous in 

 connection with the application of chemistry to technical 

 purposes. 



RuMFORD Medal. 



Professor Dr,var. 

 During more than twenty years past Prof. Dewar has been 

 engaged in researches of great difficulty, in the first instance at 

 very high, and latterly at very low temperatures, his inquiries 

 having extended over an extraordinary wide field, as will be 

 seen by reference to the "Royal Society Catalogue" of 

 scientific papers. 



In conjunction with Prof. Liveing, he has communicated to 

 the Royal Society a large number ot papers which have added 

 much to our knowledge of spectroscopic phenomena. 



During recent years he has made the liquefaction of gases a 

 subject of deepest study, and in the course ol this work has 

 displayed not only marvellous manipulative .skill and fertility of 

 resource, but also great personal courage, such researches being 

 attended with considerable danger. One of his chief objects 

 has been so to improve and develop the methods of liquefying 

 the more permanent gases that it shall become possible to deal 

 with large quantities of liquid, and to use such liquids as instru- 

 ments of research in extending our knowledge of the general 

 behaviour of substances at very low temperatures. In this he 

 has already been highly successful. Not only has he suc- 

 ceeded in preparing large quantities of liquid oxygen, but he 

 has been able by the device of v.acuuni-jacketed vessels to 

 store this liquid under atmospheric pressure during long 

 periods, and thus to use it as a cooling agent. Very valuable 

 outcome of these labours has been the series of determinations, 

 made by him in conjunction with Dr. Fleming, of the electrical 

 conductivity of metals at exceedingly low temperatures, which 

 have furnished results of a most unexpected character, and of 

 extraordinary interest and importance. Prof. Dewar's experi- 

 ment showing the great magnetic susceptibility of licjuid oxygen 

 is exceedingly important and interesting. His recent observa- 

 tions on phosphorescence, and on photography,' and on ozone- 

 at very low temperatures, have given surprising results of a 

 highly instructive and interesting character. It is difficult to 

 exaggerate the importance of extending these researches, which 

 certainly deserve all possible encouragement and support. The 

 award of the Rumford Medal to Prof. Dewar is made in 

 recognition of the services which he h.is rendered to science by 

 the work which he has already done and the provision he has 

 been .successful in making for future work, in the investigation 

 of properties of matter at lowest temperatures. 



Royal Medal. 

 Prof. J. J. Thomson, KA'.S. 



Prof. 1. J. Thomson has distinguished himself in both mathe- 

 matical and experimental fields of work. His first essay on 

 vortex rings showed power of grappling with difficult problems, 

 and added to our knowledge concerning the encounter of rings 

 which came within a moderate distance of one another so .is 

 to deflect each others' paths. 



His theoretical work in the borderland of chemistry and 

 physics has been very interesting and suggestive. His cxperi- 

 menial work has likewise been mainly on the borders of 

 chemistry and physics. He has observed the large conductivity 



t Chfiii. See, Prt't., June 28, 1894. 



-' /'//// Ma/.:, August i&^4, pp. 3j8, ajy. 



NO. 13 10. i'OL. 51] 



