272 SCIENCE AND METHOD. 



the thousandth part of the total mass ; but what is 

 there below that ? 



Of all the extraordinary voyages dreamed of by 

 Jules Verne, it was perhaps the voyage to the centre of 

 the Earth that led us to the most unexplored regions. 



But those deep sunk rocks that we cannot reach, 

 exercise at a distance the attraction that acts upon 

 the pendulum and deforms the terrestrial spheroid. 

 Geodesy can therefore weigh them at a distance, so to 

 speak, and give us information about their disposition. 

 It will thus enable us really to see those mysterious 

 regions which Jules Verne showed us only in imagi- 

 nation. 



This is not an empty dream. By comparing all the 

 measurements, M. Faye has reached a result well 

 calculated to cause surprise. In the depths beneath 

 the oceans, there are rocks of very great density, while, 

 on the contrary, beneath the continents there seem 

 to be empty spaces. 



New observations will perhaps modify these con- 

 clusions in their details, but our revered master has, at 

 any rate, shown us in what direction we must push 

 our researches, and what it is that the geodesist can 

 teach the geologist who is curious about the interior 

 constitution of the Earth, and what material he can 

 supply to the thinker who wishes to reflect upon the 

 past and the origin of this planet. 



Now why have I headed this chapter French 

 Geodesy? It is because, in different countries, this 

 science has assumed, more perhaps than any other, 

 a national character; and it is easy so see the reason 

 for this. 



There must certainly be rivalries. Scientific rivalries 



