THE DRIFTING OF THE CONTINENTS TEEMIER 235 



"And yet it does move," responded Galileo to the philosophers of 

 his time, who declared it impossible that the earth turned ; and still 

 it turns. I imagine that such is the last response of Wegener to ob- 

 jections and to criticisms. What matters — is not to Imow how and 

 why the continents drift — one will probably never know that — it is 

 to know whether they have drifted greatly in the past, whether they 

 are still drifting at the present time, and, consequently, whether Ave 

 can predict that they will drift again to-morrow. 



Of their great drifting in the past, further than the shifting of 

 the continental masses which it is necessary to admit in order to 

 explain the formation of the folded zones, that is to say, the mountain 

 chains, we are not at all certain. This absolutely necessary displace- 

 ment is to the extent of many hundreds of kilometers or perhaps a 

 thousand for a given chain; for all the chains of central Asia ex- 

 tending over hundreds of millions of years, it might on the whole 

 amount to 3,000, perhaps 4,000, kilometers. Beyond that one knows 

 nothing. 



It is undoubtedly fascinating to group all the continents of the 

 Carboniferous epoch, in order to separate them afterwards; it is 

 undoubtedly enticing to consider the chains of islands as a train of 

 stragglers behind the advancing continents, but it is not necessary. 

 These are simply convenient hypotheses. No one is claiming that 

 to-morrow others more convenient still will not be found. On the 

 other hand, there is great objection to extensive mobility. The great 

 objection is permanence; long permanence on the surface of the 

 earth, of the two features of which I have spoken, the Circumpacific 

 zone and the transverse zone, parallel to the Equator, and cutting in 

 two the hemisphere opposite the Pacific domain. 



Of the present drifting, supposing it exists, we will soon be ad- 

 vised by the near resumption of the measures of longitude with a pre- 

 cision heretofore unknown. You know that radiotelegraph already 

 permits, or soon will permit, the giving at a certain moment the 

 hour from a starting point, such as Paris, to all the gi-eat observa- 

 tories of the world. One will deduce from it, within a small number 

 of meters, the longitude of any point whatever from one of these 

 observations in a comparison with the zero meridian. After some 

 years, perhaps, one will thus know whether America is getting farther 

 away from us, as Wegener thinks; whether it is fixed in relation to 

 us; or whether the distance between us is diminishing, as I would 

 be tempted personally to think, for reasons which it would be too 

 long to here explain and which pertain to the role of the geosyn- 

 cline that I ascribe to the Atlantic. But it is to be feared that 

 the relative movement, if it exists, may be an extremely slow one, and 

 that a century may be necessary to surely establish its existence. We 

 shall then be condemned to die without knowing whether the At- 



