July 28, 1923J 



NA TURE 



125 



of finance and season, which hurried him off before 

 his ship was really seaworthy. 



The epilogue which closes the book is in Dr. Mill's 

 very best style^ and in many ways it gives us a clearer 

 picture of the man than the recital of his deeds has 

 done. 



The book is a very notable addition to the library 

 of Antarctic literature which the author has already 

 . enriched, and is singularly free from errors. We cannot 

 miss the rare luxury of correcting Dr. Mill on points of 

 fact, as for example on p. 68, where for " sea-ice " we 

 should read " barrier-ice/' or on p. 139, where for " 2000 

 feet " given as the height of the gap between Mt. Hope 

 and the mainland we should read " 900 feet." Another 

 slip of the pen is on p. 243, where the return journey 

 of Mackintosh's party over the Barrier is described 

 as " more trying even than that of Captain Scott." 

 Otherwise all comparisons are wisely avoided, nor is 

 an attempt made to assess the value of the life's work, 

 which great as it was cannot be viewed as yet in its 

 true perspective. More might have been said as to 

 the character of the innovations made by Shackleton 

 into polar work, from the point of view both of organisa- 

 tion and of methods of travel, though this was probably 

 omitted as being too technical a subject for the book. 

 If the first object of a biography is to enlist the 

 -sympathy of the reader for the man then the book 

 [is a signal success, for no one can read without emotion 

 khe vivid pictures of his doings and writings in so 

 ^skilful a setting, and if excuse were needed for this 

 [biography at all it would lie in the fact that in the 

 rapidly changing circumstances of polar organisation 

 [we may never again see such a man leading single- 

 -handed ventures to great success or triumphant 

 [failure. F. Debenham. 



The Physics of the X-Rays. 



Les Rayons X. Par Maurice de Broglie. (Recueil 

 des Conferences-Rapports de Documentation sur la 

 Physique. Vol. i. i''' Serie, Conferences i, 2, 3. 

 Edite par la Societe Journal de Physique) Pp. 

 164 + 5 planches. (Paris : Les Presses Universitaires 

 de France, 1922.) 15 francs. 



THE present volume is the first of a series of reports 

 on physics edited by the French Physical Society 

 and issued under the direction of an influential com- 

 mittee representing nearly a dozen institutions and 

 societies in France. Each report is discussed at a 

 number of conferences which are open to the public, 

 and the report in its final form is published for the 

 benefit of men of science, technicians, students, and 

 others, who wish to make themselves an courant with 

 the recent developments of the particular branch of 



NO. 2804, VOL. I 12] 



knowledge in question. That such a scheme should 

 be set afoot is not the least of a number of indications 

 of a great scientific revival which our neighbours 

 across the Channel are for their part endeavouring 

 to stimulate. 



A similar scheme has been initiated in the United 

 States under the direction of the National Research 

 Council, and already a number of volumes have been 

 published. If we except the admirable reports 

 published by the Physical Society of London, we 

 cannot recall any similar organised endeavour in 

 Great Britain to sum up the present state of knowledge 

 in the various departments of science. Nevertheless, 

 much has already been done by individual effort — as 

 is perhaps the British way — and a number of British 

 workers have already published valuable monographs on 

 the various sections of physics with which their names 

 are associated. 



If the book before us is an earnest of the standard 

 of attainment in the volumes still to come, there will 

 be a warm welcome for the new series, which, we are 

 informed, will deal with such subjects as the quantum 

 theory, the electric arc, the structure of crystals, 

 thermionics, etc. 



The treatment adopted by the Due de Broglie is 

 a revelation of the amazing achievements of the X-rays 

 in atomic physics, an^i provides many indications of 

 the ramifications of the subject into many depart- 

 ments of physics and chemistry. For example, the 

 opening pages contain an attractive discussion of 

 Bohr's theory of the atom, Moseley's law of atomic 

 numbers, and the part the quantum theory plays in 

 the phenomena of radiation. 



One is reminded that formerly the X-ray worker 

 was unequipped with a precise means of sorting out 

 the various qualities of X-rays with which he experi- 

 mented. His only recourse was filtering through metal 

 screens — a method which is relatively crude and 

 ineffective for the purpose, and, indeed, served to 

 mask a number of relations the real meaning of which 

 can only now be appreciated. Nevertheless, by the 

 insight of Barkla and others, several great and general 

 truths were discerned, which laid the foundations 

 of the subject as it has since developed. 



A new era dawned with the discovery of the dis- 

 persion of X-rays by crystals. Ihe new science of 

 X-ray spectrometry sprang into being and at once 

 turned to account the technique and precision of the 

 older optical spectrometry. Valuable as the work on 

 the analysis of the spectral lines of the optical spectra 

 had proved to be, it was transcended in simplicity 

 and potency by the newer spectrometry. To the 

 literature on X-ray spectrometry the Due de Broglie 

 has himself contributed in notable measure, and his 



D I 



