X-Rays and Crystal Structure

A BOOK in which are gathered together the results so far obtained in the new field of research concerning X-rays and crystals is particularly welcome at the present time, and especially from Prof. Bragg and his son. For not only have they carried the subject very much further than its initiators, Drs. Laue, Friedrich, and Knipping, but they have also given us an entirely new mode of experimenting. Indeed, in the hands of the English observers the investigation has already borne surprisingly important results, both as regards experimental confirmations of the views of crystallographers based on crystal measurement and as regards the nature of the X-rays themselves. The book will be gladly received by all who desire to explore the possibilities of the new method of attack, as it affords much-needed detailed descriptions of the apparatus employed, and instructions for its use. The photographic diffraction method of Laue only receives a relatively small amount of attention as the Bragg method, which involves the use of the X-ray, spectrometer, is shown to be much more capable of affording indications of the internal structure of the crystal in the more complicated eases. It is clearly shown, however, that the two methods are mutually complementary, and lead to essentially the same result, with the advantage of detail on the side of the spectrometer, and permanence of record on the side of the photographic radiogram.X-Rays and Crystal Structure.By Prof. W. H. Bragg W. L. Bragg. Pp. VII + 229. (London: G. Bell and Sons, Ltd., 1915.) Price 7s. 6d. net.