months of hard work in collaboration with his pupil, Dr. M. W. Travers, three new inert elementary gases, named neon, krypton, and xenon, were isolated from the atmosphere by means of the fractional distillation of liquefied air.
The last great period of Ramsay's work in London was characterized by another discovery of a different nature, but of equally fundamental importance, namely the proof that the emanation of radium produces helium during its atomic disintegration. In this work, in which he was assisted by Dr. F. Soddy, the first definitely recognizable transmutation of one chemical element into another was placed on a firm experimental basis. This was a fact of tremendous importance for chemical science. With the insight of genius, Ramsay now perceived that it might be possible to utilize the torrent of energy, carried by the particles shot out with enormous velocities during the atomic disintegration of radio-active substances, for the purpose of breaking down the atoms of the ordinary stable elements. Working with the emanation from radium, and as the result of a long series of experiments, he considered that he had in this way been able to obtain traces of lithium from copper and of carbon from thorium. Some of these experiments were afterwards repeated by Madame Curie, but with negative results. The final decision on this problem must be left to the future. The really important point was that just as a century earlier Sir Humphry Davy had seized on the newly discovered electric ‘pile’ of Volts as a new weapon for the decomposition of substances, so Ramsay had grasped the immense possibilities of the atomic projectiles hurled forth by exploding atoms as a new and powerful weapon for attempting the decomposition of the ordinary stable atoms of matter. The later investigations of Sir Ernest Rutherford have amply demonstrated that Ramsay was on the right track.
The last great research carried out by Ramsay (in conjunction with his pupil, Dr. Whytlaw Gray) was a marvellous example of his skill as an experimenter. This was the determination of the density, and therefore the atomic weight, of the radium emanation, the volume of this unstable gas available for an experiment being less than one-millionth of a cubic inch. This investigation, in conjunction with others, rendered it highly probable, if not certain, that the gaseous emanation given off by radium was one of the inert elements of the argon family.
Ramsay's investigations have been of cardinal importance for the advance of chemical and physical science. The mysterious α-particles so often ejected by atoms undergoing spontaneous disintegration have turned out to be positively charged helium atoms (or helium nuclei), and the helium atom or nucleus has been shown to be one of the most important constituents of the atoms of matter. The family of inert elements occupies a fundamentally important position in the modern theory of atomic structure.
Ramsay was the greatest chemical discoverer of his time, and it is safe to predict that posterity will rank him with the greatest scientific discoverers of any age. He was gifted with rare scientific insight and imagination, and was the possessor of a most wonderful skill and dexterity in the devising, constructing, and use of apparatus for the delicate and exact investigation of gases. A man of sanguine and courageous temperament, of tireless energy, and power of instant action, he fearlessly attacked problems the experimental difficulties of which would have dismayed and deterred most men. His great example of a life devoted to research, and his cheerful optimism and encouragement spurred his students to try to follow in his footsteps, and enabled him to build up a great school of chemical research at University College.
Ramsay was endowed with extraordinary personal charm, and a most kindly, generous, and gentle disposition. No man was ever more beloved by his students, who found in him not only a great and inspiring teacher and investigator but also a true and generous friend. An excellent linguist and musician, a witty and humorous speaker both in public and in private, Ramsay's personality endeared him to an immense circle of friends and acquaintances in many countries. The quickness and receptivity of his mind were very remarkable, so that he was ever the enthusiastic friend and exponent of new advances in science. Thus he was one of the first chemists in England to teach and expound the work of W. Ostwald, J. H. van't Hoff, and S. A. Arrhenius, as in later life he was one of the first to take up work in the new field of radioactive change. His activities extended in many directions. He found time to write a number of excellent books on chemistry, was an ardent apostle of reform in converting the university of London into a great teaching university, and served as a member of the royal commission on
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