The Frontiers of the Sciences 



considered only as masses in movement? What 

 is the matter composing the sun, the planets, 

 the stars, the nebulae and the comets? 



The interest of all these phenomena is patent 

 to everybody, and Kepler's laws are impotent 

 to explain them. We receive only one thing 

 from our fellow-travellers through space, namely, 

 radiations, but how varied in range chemical, 

 luminous and calorific radiations probably also 

 electro-magnetic waves, like those of wireless 

 telegraphy, and perhaps others hitherto un- 

 known and unsuspected. It will be necessary 

 to examine all these radiations and extract from 

 them information about the distant regions 

 whence they come, organising our investigation 

 methodically by adapting the methods of physics 

 to the new conditions. There is no lack of dis- 

 coveries made or hoped for. We are beginning 

 to understand the nature of the external layer* 

 of the sun and its movement of rotation. We 

 have collected facts regarding the temperature, 

 the chemical constitution and the physical state 

 of the stars. We have processes of extreme 

 delicacy for determining their dimensions and 



their displacement relatively to our globe; 



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