Taken from The Daily Express, Thursday, July 6, 1911
We regret, to record the death of Dr. G. Johnstone Stoney, F.R.S., the distinguished Physicist and Mathematician, which occurred at his London residence yesterday, at the venerable age of 84 years. Dr Johnstone Stoney was one of the most eminent scientific men that Ireland has produced and was also one who for many years took an important part in the educational development of the country as the Secretary of the Queen's University in Ireland, until the latter was superseded by the late Royal University. George Johnstone Stoney was born in February, 1826, and was the eldest son of Mr. George Stoney, of Oakley Park, King's County. The entered Trinity College, Dublin, and after a distinguished University career became the first regular Astronomical Assistant to the Earl of Rosse at the then recently established Observatory at Birr. Here Stoney was in a thoroughly congenial scientific environment, and was free to pursue his favourite studies in mathematics and physics. His conspicuous abilities soon led to his appointment to the Professorship of Natural Philosophy at Queen's College, Galway; and after five years of strenuous work in that chair he was called to the highly important office of Secretary of the Queen's University. In that position he gave abundant proof of his great mental grasp of difficult educational problems and of his administrative capacity. So thoroughly was Johnstone Stoney identified with the liberal and unsectarian character of the Queen's University that he retired in 1882, when political considerations led the Government of the day to adopt the materially different policy represented by the Royal University--now in turn replaced by the new National University. Dr. Johnstone Stoney's loss to University education in Ireland represented a gain in other directions' as he was able to devote much more time to the scientific work which he pursued, with unabated power during the remainder of his long life. He was also free, while still resident in Dublin, to devote no small part of his energy to furthering the progress of that many-sided and valuable institution, the Royal Dublin Society.
In 1893 family considerations led Dr. Stoney to live in London, where he continued to pursue his researches until failing health obliged him to avoid undue application to tho work he loved. His interest in all scientific questions of the day was unabated to the last, and his opinions on many difficult problems in solar and general physics were highly valued and often sought for by eminent men at home and abroad. He was a man of noble character, of wise, kindly, and sympathetic disposition, the soul of honour and a generous friend.
Of Dr. Johnstone Stoney's scientific work space permits to give no more than some idea of its vast range. He was associated early in life with the late Provost Lloyd, F.R.S., of Trinity College, Dublin, in the magnetic survey of Ireland, but the work to which he always attached most importance was that on the constitution of the sun and the development of molecular physics. His long memoir on solar physics is now regarded as a classic on the subject. His far-reaching explanations of the mode of escape of gases from planetory atmospheres has also received much support from recent writers. He showed that, when the temperature is high enough and the mass of the gaseous molecule small enough, then a molecule on the confines of the atmosphere of a planet will sometimes move with a velocity sufficient to carry it quite away from the attractive influence of planets below a certain mass. The gaseous atmosphere, therefore, of a planet, can only consist of molecules sufficiently heavy for that planet to retain them, or else the gas is still in process of leaking away from such a planet. Dr. Stoney thus explained the absence of atmosphere from our small moon, and was strongly of the opinion that helium is now escaping from the earth. Later on he foretold on this reasoning, that some considerable source of helium must exist on the earth when Sir William Ramsay discovered its presence on our planet. Helium was later on shown to be constantly supplied through hot springs, etc., and to be radioactive in origin.
Dr. Stoney held that Mars is too small to retain water, thus entering from the mathematical point of view into the controversy yet unsettled as to the presence or not of water in Mars. The American observer, Lowell, and others maintained the presence of water, and even possibly life as we know it. Observers disagreed and Dr. Stoney considered from mathematical reasoning that the " snow " caps on Mars are more probably due to the heavy gas carbon dioxide. Mars is smaller than the earth and farther from the sun. Dr. Stoney considered Mars too small to retain water in its atmosphere, and the temperature probably much too cold for the presence of water in a liquid or cloud state. The changing ruddy colour of the planet Dr. Stoney attributed to some of the oxides of nitrogen in its atmosphere which change colour with the temperature--so giving the Martian seasonal changes of colour. Recent researches by Poynting support Stoney's view by showing that the temperature of Mars is probably some hundred degrees below the freezing point of water.
At the Belfast meeting of the British Association in 1874 he showed that the real meaning of Faraday's laws of electrolysis is that electricity, like matter, consists of ultimately indivisible equal particles or atoms, and he suggested the name of " Electron " for these atoms--he further gave the first estimate of their electric quality. Stoney's name of " Electron " is now universally used, but the remarkable fact of their existence is often assumed to have been first shown by Von Helmholtz, who gave practically the same explanation of the electrolytic laws some years afterward in his Faraday Lecture of 1881.
When Clausius' work on the Kinetic Theory of Gases was published Stoney saw at once in 1867 that it gave a clue from which could be obtained the number of molecules in a given volume of gas under standard conditions, and so the actual mass of the atom of any given chemical element. Sometime after the publication of his paper, Lord Kelvin gave a similar estimate, and a few months earlier another estimate had been made in Germany. The investigators worked independently and unaware of the previous work. In 1891, Stoney showed that the waving about of the electrons inside a gaseous molecule in orbital motions with perturbations very similar to planetary perturbations must be the cause of lines in the spectrum; the only other possible cause, that of Hertzian waves through electric discharge in the molecule itself being impossible through their great rapidity. This last was shown by Stoney's nephew, George FitzGerald, F.R.S. Stoney showed that double or triple lines would be caused if an apsidal motion be imposed on an elliptic orbit for the electrons inside a molecule. This was experimentally verified later on when Zeeman showed that in some cases a spectrum line can be tripled under the disturbing influence of a magnetic field. A list of Stoney's papers and an estimate of his work was issued by the Royal Dublin Society at the time when the Boyle Medal was conferred upon him. His subsequent work has been upon various subjects notably on microscopic vision. His papers on Ontology reveal to some extent the philosophical basis of Stoney's scientific thought. His mental attitude towards science was of the widest; for he not only appreciated to the full the value of vigorous mathematical demonstration, but also was of an essentially speculative turn; freely using surmise as the basis of investigation. His love of exactitude, again, is revealed in the attention he devoted to scientific nomenclature and the proper choice and definition of units. Dr. G. Johnstone Stoney received many honours. He was a Fellow of the Royal Society for nearly fifty years. He was D.Sc, honoris causa, of Dublin and of the Queen's University. He was a visitor of the Greenwich Observatory and of the National Library and Museum at Dublin. He served on a Royal Commission on University Education in Ireland. He was honorary secretary to the Royal Dublin Society for over 20 years, and then served as a vice-president. He was president of section "A" at the meeting of the British Association in Sheffield. He was awarded the first Boyle medal as a mark of the position in which he was held amongst Irish scientific men. He was a member of the Committee of the British Association which' chose the C.G.S. Units now in universal use in scientific work; he was a member of the joint committee of the Royal Society and the Royal Astronomical Society on solar Research, and of many others. He was a foreign member of the Academy of Science at Washington and of the Philosophical Society of America founded by Franklin. He was a corresponding member of the Academy of Sci. di. Lettore ed Arti., Benevento. Dr. Stoney married his cousin Miss Margaret Stoney. He leaves two sons and three daughters. His eldest son Gerald Stoney, has recently been nominated for Fellowship in the Royal Society; he has been awarded the Watt medal of the Inst. Electrical Engineers. He is manager in the Turbine works of the Hon. Charles Parsons, C.B., F.R.S. The second son is a doctor in Australia. One daughter is a Lecturer at the London School of Medicine for Women, and another daughter is a London Physician. His brother, Mr. Bindon Stoney, F.R.S., Engineer of the Port of Dublin, predeceased him two years ago. The late Prof. George Fitzgerald F.T.C.D., F.R.S., was a nephew. General Sir Bindon Blood, R.E, G.C.B., and Edward Stoney, C.I.E., are cousins. Professor Maurice Fitzgerald of Belfast is another nephew.