Cviii PKOCEEDINGS OF THE GEOLOGICAL SOCIETY. [vol. lxxix, 



long after by the isostatic forces, the energy being traceable to 

 the stored radioactive heat of prior ages. 



Inter -revolutionary events consist of 'preparatory' dis- 

 turbances, due to local increase of liquefaction of the magma : 

 also of ' sequential ' disturbances, due to relief of strain accumu- 

 lated during revolution, and to the restoration of isostatic 

 equilibrium. 



The conditions now prevailing beneath the continents preclude 

 the establishment of a steady state (that is, of thermal equilibrium), 

 and in the past always must have done so. 



The cyclical events outlined in the theory here adduced appear 

 to be inevitable as a consequence of radioactivity and isostasy. 

 Cyclical disturbances alone can explain the past history of the 

 Earth's surface. 



A cordial vote of thanks was unanimously accorded to the 

 Lecturer by the Fellows present. 



May 16th, 1923. 



Prof. W. W. Watts, Sc.D., F.R.S., Vice-President, 

 in the Chair. 



Harold Francis Banks, Chase Road, Burntwood, near Lichfield 

 (Staffordshire) ; Arthur Delmar Combe, Geological Survey of 

 Uganda, Entebbe (Uganda) ; and Robert Murray-Hughes, Sable 

 Antelope Mine, Mumbwa (Northern Rhodesia), were elected 

 Fellows of the Society. 



Prof. Lucien Cayeux, 6 Place Denfert-Rochereau, Paris XI Verne ; 

 Prof. John M. Clarke, LL.D., Director of the New York State 

 Museum, Albany (N.Y.), U.S.A. ; Prof. Henri Douville, 207 Bou- 

 levard Saint-Germain, Paris Vlleme ; and Prof. Waldemar Lind- 

 gren, Massachusetts Institute of Technology 7 , Boston (Mass.), 

 U.S.A., were elected Foreign Members of the Society. 



Prof. Emile Argand, University of Neuchatel (Switzerland) ; 

 Prof. Leon William Collet, University of Geneva (Switzerland) ; 

 Prof. Reginald Aldworth Daly, 23 Hawthorn Street, Cambridge 

 (Mass.), U.S.A. ; Prof. G. Delepine, 13 Rue de Toul, Lille (Nord), 

 France ; Prof. Paul Fourmarier, 140 Avenue de l'Observatoire, 

 Liege (Belgium) ; Prof. Victor Moritz Goldschmidt, Universitetets 

 Mineralogisk Institut, 23 Trondhjemsveien, Christiania (Norway); 

 Prof. Thore Gustafsson Halle, Naturhistorisk Riksmuseum, 

 Stockholm 50 (Sweden) ; Prof. James Furman Kemp, Columbia 

 University, New York City, U.S.A.; Prof. Carl Frederik Kolderup, 

 University of Bergen (Norway) ; Prof. Carlos I. Lisson, Escuela 

 de Ingenieros, Lima (Peru) ; Prof. Gustaaf Adolf Frederik 

 Molengraaff, 60 Voorstraat, Delft (Holland) ; Dr. Armand Renier, 



