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 LXXXVI. Notices respecting JS T etv Books. 



Some Problems of Geodynamics. By A. E. H. Loye, M.A., D.Sc, 

 F.R.S. Cambridge University Press. 1911. 



The Tides and Kindred Phenomena of the Solar System. By Sir 

 George Howard Darwix, K.C.B. Third Edition. London: 

 John Murray, 1911. 



Professor Bote's Essay was awarded the Adams Prize in the 

 University of Cambridge in 1911. It is a mathematical treatise 

 which discusses the origin and nature of the various stresses which 

 exist in the interior of the earth. The problems attacked and the 

 main conclusions reached are given iu non-mathematical form in 

 an introductory Abstract of 17 pages ; and in most of the chapters 

 the average reader will find pastures of easy English on which to 

 feed his scientific curiosity. 



Differing in form and yet treating in part of some of the same 

 problems, Sir George Darwin's book on the Tides, originally 

 published in 1898, is now issued in its Third Edition. The 

 kindred phenomena spoken of in the secondary title include dis- 

 cussions of Saturn's Kings and Satellite systems in general, of the 

 origin of spiral nebulae and double stars, and in fact the evolution 

 of the cosmos. Tidal action in the true Newtonian sense of the 

 term is the never ceasing agency which brings about the wonder- 

 ful variety of configuration of stellar systems distributed through 

 space. 



The most important of the problems discussed by both authors 

 is the tidal deformation of the earth's crust, the existence of which 

 was first demonstrated a few years ago by Dr. Hecker of Potsdam, 

 now of Strassburg. The search for this yielding of the earth 

 as a whole to the tidal action of sun and moon was initiated in 

 1863 by Lord Kelvin, then William Thomson ; but it was not till 

 the lapse of 4-1 years of strenuous endeavour on the part of several 

 independent investigators that a definite result was gained. An 

 unlooked-for lack of symmetry in the amount of yield of the 

 earth's crust is made the subject of a special investigation by 

 Professor Love ; and following his suggestions the International 

 Seismological Association have determined to instal suitable instru- 

 ments in variously situated localities near to and far from the 

 ocean. 



Among other interesting questions, Professor Love works out 

 the problems of gravitational instability, first expounded by Jeans, 

 and concludes his essay with a thorough discussion of the vibra- 

 tions of a gravitating compressible planet and the propagation of 

 seismic waves through the mass or over the surface. One general 

 conclusion of all this recent research is thus put by Sir George 

 Darwin : " Although there are still some — principally amongst 

 geologists — who believe in the existence of liquid matter under 

 the solid crust of the earth, yet the arguments which I have 

 sketched appear to most men of science conclushe against such 

 belief." 



