362 Geological Society : — 



radium emanation by the density method where that method is 

 treated. Recent work on osmotic pressure is well discussed. 



The book possesses all the valuable features of the first edition, 

 and the larger format in which it is now printed shows a great 

 improvement on the old in both appearance and convenience in 

 handling. 



X Rays and Crystal Structure. By W. H. Bragg, M.A., D.Sc, 

 F.E.S., and W. L. Bragg, B.A. George Bell & Sons. Third 

 Edition. Pp. vii+229. Price 8s. U. net. 

 It is pleasant to find that, in spite of the war, a third edition of 

 this book has been called for. No alteration of any importance 

 has been made since the first edition, which gave a wonderfully 

 clear and concise account of the researches which led to the use of 

 crystals as diffraction gratings for X rays, and afterwards revealed 

 so much of the structure of crystals ; researches to which Professor 

 Bragg and his son contributed so much. It is to be hoped that 

 the next edition will see the war ended, and the authors, at 

 present employing their ingenuity in the fight against the common 

 enemy, continuing their investigations in a field which they have 

 cultivated to such purpose. 



XL. Proceedings of Learned Societies. 



GEOLOGICAL SOCIETY. 



[Continued from p. 280.] 



March 20th, 1918.— Mr. G. W. Lamplugh, F.E.S., President, 

 in the Chair. 



Dr. W. F. Smeeth delivered a Lecture on the Geology of 

 Southern India, with particular reference to the Archaean 

 Rocks of the Mysore State. With the aid of a map, prepared 

 by the Geological Survey of India, the Lecturer pointed out the 

 general character of the geological formations of Southern India, 

 which consist, very largely, of a highly folded and foliated complex 

 of Archaean gneisses and schists, followed by some considerable 

 patches of pre- Cambrian slates, limestones, and quartzites; with 

 these are associated basic lava-flows and ferruginous jaspers. The 

 remaining formations consist of remnants of the Gondwana Beds 

 (coal-measures of Permo- Carboniferous age), a few patches of 

 Cretaceous rocks, some Tertiary and Pleistocene deposits, and 

 recent sands and alluvium, all situated along the coastal margins 

 of the Peninsula. He contrasted the scanty post- Archaean record 

 of Southern India, the apparent non-submergence of the greater 

 portion of the area and its freedom from great earth-movements 

 since Archaean times, with the widely- extended formations of 

 Northern India which recorded oft-repeated movements of de- 

 pression and elevation, culminating in the rise of the Himalaya 

 in Tertiary times and accompanied by igneous activity on a 

 gigantic scale, as proved by the outpourings of the Deccan Trap. 



