NOTES 307 



assistant at his old University. Here, in spite of the strong prevailing trend 

 towards lorganic chemical research, his natural leanings towards physical chemistry 

 began to show themselves, and one of his earliest researches was on the deter- 

 mination of vapour densities by the use of pitch-pipes, in carrying out which his 

 musical ear was turned to good account. 



In 1880 he accepted the post of Professor of Chemistry at Bristol College, 

 where, in collaboration with Prof. Sydney Young, he carried out those important 

 researches on vapour pressures which have become classical. 



In 1887 the Chair of Chemistry at University College having fallen vacant 

 through the resignation of Prof. Alexander Williamson, Prof. Ramsay accepted 

 the post. At University College those researches on the rare gases of the 

 atmosphere were undertaken which, more perhaps than any others, brought 

 Prof. Ramsay's name into the very front rank of chemical investigators. 



Lord Rayleigh had noticed whilst examining the density of nitrogen obtained 

 from various sources that the samples of atmospheric nitrogen were consistently 

 slightly heavier—by about one-thousandth part — than those obtained by other 

 methods. Cavendish in 1784 had noticed that after removing the chief components 

 of air, oxygen and nitrogen, there was always a small residue of less than a per 

 cent, which could not be removed by chemical treatment. There the matter had 

 remained for a century, but taken in conjunction with later observations the 

 suggestion offered itself that there were present in the atmosphere small quantities 

 of an unknown inert gas. 



Sir William Ramsay, working quite independently of Lord Rayleigh, had found 

 that atmospheric nitrogen after absorption by red-hot magnesium always left a 

 residue unaffected by the metal. The two great scientists, becoming aware of 

 each other's work, decided to pursue the investigation conjointly, and as a result 

 of their researches they were able in 1894 to announce to the meeting of the 

 British Association the discovery of a new gas in the atmosphere, which, on 

 account of its chemical inertness, they named Argon. 



Later, working with Dr. M. W. Travers, Prof. Ramsay was able to show that 

 even " Argon " obtained from the air was not homogeneous, but contained a whole 

 family of five inert elements — helium, argon, neon, krypton, and xenon. 



When it is considered that there is only one part of xenon in seventy million 

 parts of air, one begins to realise the immense difficulty of the research, but Prof. 

 Ramsay's unique skill in glass-blowing and his almost uncanny powers of working 

 with microscopic quantities of substances enabled him to carry out his researches 

 successfully, even with quantities of such nightmare-like minuteness as would 

 appal most men. 



It is, perhaps, worthy of note that to-day certain firms are in the habit of selling 

 compressed argon, obtained as a by-product from liquid air distillation, as an 

 ordinary article of commerce : a far cry indeed from the infinitesimal amounts 

 obtained at first by Ramsay and Rayleigh in their work — sometimes alluded to as 

 " the triumph of the third place of decimals," as indicating the minute difference in 

 the densities which gave rise to the research ! 



Of the other work of Sir William Ramsay the most widely known is, perhaps, 

 that connected with radium and its emanation, in the course of which he was able 

 to prove that helium is produced from radium, as a product of atomic disintegra- 

 tion, and so for the first time that chimera of the alchemists, the transmutation 

 of the elements, was shown to be an actual fact. 



It would take too long to enumerate the full course of these discoveries, but 

 here also Prof. Ramsay's skill as a manipulator and his almost miraculous power 



