232 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1924 



which Wegener supposes but does not explain, and how this same 

 theory accounted for the displacement of the continental masses, 

 which one searches for in vain in the German theory. But there 

 are many hypotheses in the theory of Emile Belot; there is, above 

 all, the hypothesis of the transport of the earth at an enormous 

 speed to the midst of a tranquil nebula, "transport en projectile," 

 which the author uses with admirable ingenuity. This furnished 

 him with an exterior force, the resistance from the nebula, which 

 he called "the wind of the nebula." As the earth, in the hypothesis 

 of Belot, travels in a direction parallel to its axis, the North Pole 

 forward, the two poles are very imequally swept by this nebula 

 wind. When the deluge of the primoidial waters fall on the slightly 

 cooled earth it will take the form of frightful squalls, generators 

 of the most frightful torrents, capable of sculpturing the soft crust; 

 these torrents accumulate the sal at the North Pole and, on the 

 other hand, denude the sima at the South Pole; they hollow out pro- 

 foundly the bed of the oceans and will give to the continents their 

 definite pointed form toward the south. It is further, the wind of 

 the nebula which, by retarding the terrestrial rotation, very un- 

 equally, according to the latitude and very differently in the two 

 hemispheres, furnished Emile Belot an explanation of the twisting 

 of the continents toward the east and, in a general way, that of the 

 tangential displacements parallel to the Equator. As to the tan- 

 gential displacements parallel to the meridians, the author explains 

 them by means of a new hj'pothesis — the hypothesis of the periodic 

 fall on the earth of many satellites in annular form, analogous to 

 the rings of Saturn. Thus ingeniously everything is accounted for 

 and it is surely a very amusing effort, but it can not be proved. 



Very recently, also, an English scientist, J. Joly, gave his inter- 

 pretation of the theory of the drifting of the continents, making 

 appeal to radioactivity to supplement the German thesis, thus mak- 

 ing it capable of explaining a greater number of phenomena. Joly 

 admits, as does Wegener, the existence of a spherical envelope of 

 basalt all around the globe, under the continents, and under the 

 oceans; but he reminds us that most of the rocks that we know are 

 radioactive. The basalt of the profound depths is therefore radio- 

 active; it consequently constitutes a practically indefinite source of 

 heat. One might think that the emanations from this source would 

 be constant. But Joly in his hypothesis makes the flow variable and 

 periodic. The release of heat, through the disintegration of the 

 ladioelements, is by paroxysms, separated by long periods of in- 

 action. Hence the deplacement of the isogeothermal regions in the 

 interior of the earth; they rise or fall; and the sphere of basalt, 

 which supports the continents and oceans, is sometimes formed of 

 solid basalt, sometimes becoming liquefied very near the surface and 



