August io, 191 6] 



NATURE 



483 



in the fullness of time was again to link itself 

 with its source. 



It has been well remarked of Ramsay that he 

 stood to the outside world for an essentially 

 British school of chemistry. To describe him as 

 arig-inal would be like saying water is wet. He 

 was of the essence of originality, and, during the 

 time the writer knew him, entirely without any 

 apparent sheet-anchor of fixed conviction or estab- 

 lished belief in scientific doctrine, which at all 

 times, in a science somewhat prone to let go sheet- 

 anchors, made him a unique and almost incom- 

 prehensible personality. It is true that in his later 

 years he suffered from the defects of these quali- 

 ties, and he failed to criticise sufficiently his own 

 ideas and experimental results before making them 

 public. He seemed to lose something of that 

 sense of the great and terrible responsibility which 

 must at all times rest heavily on the scientific 

 leader, and never more than in the case of the 

 pioneer. All through his work, probably, his col- 

 laborators had perforce to assume to an undue 

 extent the role of "devil's advocate," and much of 

 his best work was done in partnership with those 

 who recognised this. But in the zenith of his 

 powers at University College and in the full swing 

 of his elucidation of the family of inert gases, he 

 trod fearlessly and without an error the difficult 

 path of the pioneer and won a permanent right to 

 something far greater than the title of a successful 

 discoverer. Argon, helium, neon, krypton, and 

 xenon were capital discoveries, but the bringing of 

 this group into harmony with the rest of the ele- 

 ments might have appeared a task almost insuper- 

 able in the face of their total lack of chemical 

 properties. The recognition that they were mon- 

 atomic and non-valent gases occupying a "zero" 

 family of the Periodic Table, preceding that of 

 tne monovalent alkali-metal family, from which 

 hitherto the table had seemed to start, was made 

 in spite of the fact that argon itself is an "excep- 

 tion," in the orderly sequence of elements, of the 

 same type as tellurium, which was then a very 

 hotly debated and puzzling question. 



This was physical chemistry in a sense as origi- 

 nal and bold as the great thermo-dynamical and 

 electro-chemical generalisations of the American 

 and Continental savants, which hitherto had 

 almost monopolised the term.' It initiated a 

 widening of the domain that was to grow apace. 

 The human mind seems incapable in its initial 

 processes of grasping thoroughly more than one 

 fundamental point of view at a time. Each has 

 to be grasped separately before both eyes can be 

 opened without the image becoming blurred. The 

 phlogistonists had a single eye for what we now 

 call energy, Lavoisier for what we now call mass. 

 The first physical chemists found the thermo- 

 dynamical point of view so ciear-cut and complete 

 that some of them sought to banish from their 

 conceptions the molecular and atomic viewpoints 

 as unnecessary, unproved, and unprovable hypo- 

 theses. Ramsay, confronted with a type of element 

 utterly devoid of chemical properties and forced 

 to rely entirely on their physical properties to put 

 them in their proper relation to the whole, solved 

 NO. 2441, VOL. 97] 



the problem completely and correctly by the aid of 

 the molecular and atomic conceptions alone, 

 though it is only lately that opposition to his views 

 has entirely died down. Before he died he had 

 the satisfaction of seeing this his own side of 

 physical chemistry developed, by the discoveries 

 in connection with radio-activity and the Brownian 

 movement, to an amazing extent. The physical 

 reality of atoms and molecules has been demon- 

 strated by methods of great directness and power; 

 and these, incidentally, applied to the case of his 

 own gases, confirmed his earlier interpretation of 

 their monatomic character in a way that made 

 further cavil impossible. 



But now we must go back to 1896, to the year 

 of the discovery of helium and to the year that 

 Henri Becquerel in Paris discovered the radio- 

 activity of uranium, but a few months after 

 Rontgen had given to the world a sixth sense. In 

 Becquerel's footsteps M. and Mme. Curie were 

 starting on the quest which led to radium. 

 Rutherford had come from the mirror image of 

 our islands in the Southern Seas to learn at the 

 Cavendish Laboratory under Sir J. J. Thomson, 

 and with him to forge the weapons of measure- 

 ment and discrimination which, in the new sciences 

 that the dying century had called forth, were to 

 prove their sufficiency. His specific recognition 

 of the o-rays was one of the first-fruits of the new 

 methods, which, a little later, in Canada, at the 

 McGill University, in the fine Macdonald science 

 laboratories, were to play such an important part 

 in the amazing succession of discoveries that 

 followed, and which culminated in the complete 

 and satisfying explanation of radio-active pheno- 

 mena which is accepted to-day. 



Then, by one of the strangest combinations of 

 destiny, the centre of interest shifts again for the 

 moment back to the laboratory where helium was 

 discovered, as the associate of uranium and 

 thorium in minerals, seven years before, to Sir 

 William's private laboratory at University 

 College. Word had passed along the under- 

 ground corridors below, and the room had swiftly 

 and silently filled with a throng of staff and 

 students, clustering round those fortunate enough 

 to possess a pocket spectroscope, all making the 

 one short remark, "Yes! it's helium." For that 

 was the room where was being put the coping- 

 stone to the arch that in seven short years had 

 sprung up from the twin discoveries of the rare 

 gases and of radio-activity, and Sir William was 

 witnessing with the spectroscope the first ocular 

 proof of the genesis of helium from radium, which 

 had been predicted from the theory of atomic dis- 

 integration. Nobody can deny that destiny, so 

 frequently erratic, here made a happy choice, not 

 only because the original discovery of helium was 

 made by Ramsay, but also because in his labora- 

 tory had been worked out those delicate methods 

 of gas manipulation which alone were equal to 

 dealing with the minute amounts of helium 

 involved in this investigation. 



In another direction there was an intimate con- 

 nection between the discovery of the Inert gases 

 and radio-activity. The "radio-active emana- 



