Modern Spectroscopy

Abstract

THE three Cantor lectures on the above subject, delivered by Prof. H. Dingle to the Royal Society of Arts in November and December 1934, have now been published (London: Royal Society of Arts, 1935. 2s. Qd.}. They deal with the spectra of atoms, molecular and absorption spectra, and applications of Spectroscopy. The first lecture outlines the main characteristics of atomic spectra, primarily from the experimental point of view. The second deals, in a rather more detailed manner, with band spectra; some indication is given of how these arise, and of their structure. The subject of absorption spectra is also touched upon. The non-physicist, to whom the lectures were primarily addressed, will find the third lecture, on the applications of Spectroscopy, of particular interest and value, since it contains a good deal of matter not readily available elsewhere. The difficulties of qualitative and quantitative spectrum analysis are clearly set forth, and the present possibilities of such methods are indicated, some interesting examples being cited. This particular application of Spectroscopy is, of course, older than any other, but unexpected obstacles to its general application were encountered at an early stage, and until recently the method has been neglected to such an extent that the very meaning of the term ‘spectrum analysis’ is apparently unfamiliar to some of the younger physicists of the present day, with whom it connotes the analysis of spectra, for physical purposes, instead of analysis by spectra for chemical purposes. Concerning the section devoted to astronomical Spectroscopy, it need only be said that in lucidity and interest it is quite representative of the author's well-known writings on this subject. The text is well illustrated throughout by diagrams and reproductions of spectrum photographs. The lectures will without doubt appeal to a wide circle of readers, that is to say, all those who have no special knowledge of Spectroscopy but wish to obtain a general idea of what it is about and what is its contribution to the general body of scientific knowledge.