556 SCIENCE PROGRESS 



Stratigraphical and Regional Geology. The most notable 

 recent work is the following : 



HoLTEDAHL, O., "A TiUite-like Conglomerate in the ' Eo Cambrian ' of 



Southern Norway," Amer. Journ. Sci., 4, 1922, pp. 165-73. 

 Bucking, H., " Beitrage zur Geologic des oberen Brauschtals in den Vogesen," 



Nenes Jahrb., Beil.-Band., 44, 1920, pp. 100-273. 

 Grosse, E., " Grundlinien der Geologie und Petrographie des ostlichen 



Katanga," Neues Jahrb., Beil.-Band., 42, 1918, pp. 272-419. 

 Wanner, J., " Beitrage zur Geologie und Geographie von Nordost-Borneo," 



Neues Jahrb., Beil.-Band., 45, 1921, pp. 149-213. 

 Benson, W. N., " An Outline of the Geology of New Zealand," Journ. GeoL, 



30, 1922, pp. 1-17. 

 BoswoRTH, T. O., Geology of the Tertiary and Quaternary Periods in the 



North-west Part of Peru, Macmillan & Co., Ltd., London, 1922, pp. 434, 

 Heald, K. C, and Mather, K. F., " Reconnaissance of the Eastern Andes 



between Cochabamba and Santa Cruz, Bolivia," Bull. Geol. Soc. Amer., 



33, 1922, pp. 553-70- 

 Mather, K. F., " Front Ranges of the Andes between Santa Cruz, Bolivia, 



and Embarcacion, Argentina," ibid., pp. 703-64. 



CRYSTALLOGRAPHY. By A. Scott. M.A., D.Sc. 



Although only ten years have elapsed since the publication 

 of the original paper by W, Friedrich, P. Knipping, and M, von 

 Laue [Sitzber. Akad. Miinchen, 303, 191 2) on the investigation 

 of crystal structure by means of X-rays, a large volume of 

 literature on the subject has already accumulated. The 

 results of the work of the last decade are summarised in a 

 series of papers in a recent number of Die Naturwissenschaften 

 (Heft 16, 1922). An historical account of the investigation of 

 the interference phenomena of X-rays is given by W. Friedrich 

 {ibid., 363, 1922), and P. Knipping {ibid., 366, 1922) describes 

 the various methods which have been devised in X-ray spectro- 

 scopy. The results of the work on the latter subjects are dis- 

 cussed by G. Wentzel {ibid., 369, 1922), who tabulates the 

 absorption limits and the wave lengths of the K-, L-, and Mi- 

 series for the appropriate chemical elements. The wave 

 length of X-rays is treated by L, Meitner {ibid., 381, 1922), 

 and the bearing of Laue's work on atomic structure by P. Debye 

 {ibid., 385, 1922), The significance of the Laue radiogram 

 from the point of view of crystallography is considered by 

 P. Niggli {ibid., 391, 1922), who summarises the results of the 

 examination of those crystals which have been successfully 

 investigated. E. Schiebold {ibid., 399, 1922) gives a detailed 

 account of the operations involved in the interpretation of the 

 X-ray analysis of a crystal. Bibliographies are appended to 

 several of the papers. Attention may also be drawn to a dis- 

 cussion, by R. Gross {Fortsch. Min., 7, 65, 1922), of the main 

 methods of investigation, Laue's, Bragg's, and Debye and 

 Scherrer's, and the interpretation of the results. 



