![]() ![]() The next step in the enquiry was, if possible, to exaggerate the discrepancy. If the chemically derived nitrogen were partly dissociated into its component atoms, then the lightness of the gas so prepared would be explained. For, before going further, I ought to explain that, in the nitrogen obtained by the ammonia method, some-about a seventh part-is derived from the ammonia, the larger part, however, being derived as usual from the atmosphere. Several persons who wrote to me privately were inclined to think that the explanation was to be sought in a partial dissociation of the nitrogen derived from ammonia. I obtained various useful suggestions, but none going to the root of the matter. In order, if possible, to get further light upon a discrepancy which puzzled me very much, and which, at that time, I regarded only with disgust and impatience, I published a letter in Nature inviting criticisms from chemists who might be interested in such questions. The gas obtained by the copper method, as I may call it, proved to be one-thousandth part heavier than that obtained by the ammonia method and, on repetition, that difference was only brought out more clearly. The usual method consists in absorbing the oxygen of air by means of red-hot copper and I thought that I ought at least to give that method a trial, fully expecting to obtain forthwith a value in harmony with that already afforded by the ammonia method. But then I reflected that it is always advisable to employ more than one method, and that the method I had used-Mr Vernon Harcourt's method-was not that which had been used by any of those who had preceded me in weighing nitrogen. That method is very convenient and, when I had obtained a few concordant results by means of it, I thought that the work was complete, and that the weight of nitrogen was satisfactorily determined. The excess of ammonia is subsequently absorbed with acid, and the water by ordinary desiccating agents. In its passage the oxygen of the air combines with the hydrogen of the ammonia, all the oxygen being in that way burnt up and converted into water. Air is bubbled through liquid ammonia, and then passed through a red-hot tube. In this method the oxygen of ordinary atmospheric air is got rid of with the aid of ammonia. It was not until after that lecture that I turned my attention to nitrogen and in the first instance I employed a method of preparing the gas which originated with Mr Vernon Harcourt, of Oxford. ![]() I must take that as known, merely mentioning that it is substantially the same as is used by all investigators nowadays, and introduced more than fifty years ago by Regnault. It is not necessary, therefore, that I should trouble you to-night with any detail as to the method by which gases can be accurately weighed. It is some three or four years since I had the honour of lecturing here one Friday evening upon the densities of oxygen and hydrogen gases, and upon the conclusions that might be drawn from the results. Īrgon Royal Institution Proceedings 14, 524-538 (1895) Meanwhile Rayleigh's lecture provides a compelling example of careful scientific practice, tracking down a small anomaly to what proved to be an interesting and important discovery. We will see the placement of argon and its family of elements proposed in the next chapter. It is appropriate to consider the discovery of argon among papers about the periodic system, because the atomic weight of argon and its properties were such that there seemed no place for it in the periodic system of the time. ![]() The story of that discovery is recounted here in the transcript of a lecture for interested laypersons at the Royal Institution of Great Britain, where he was Professor of Natural Philosophy. He received the Nobel Prize in physics in 1904 for his role in the discovery of argon. Argon, a new element Elements and Atoms: Chapter 14Īrgon, a new element Lord Rayleigh (1842-1919, born John William Strutt, was a physicist well known for his work in acoustics and optics (the sciences of sound and light respectively). ![]()
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