Masterpieces of Science 



striking phenomena which characterize the pro- 

 gress of terrestrial or planetary magnetic storms. 



When we remember that what is true of a 

 relatively great solar disturbance, such as the 

 one witnessed by Messrs. Carrington and Hodg- 

 son, is true also (however different in degree) of 

 the magnetic influences which the sun is at 

 every instant exerting, we see that a new and 

 most important bond of union exists between 

 the members of the solar family. The sun not 

 only sways them by the vast attraction of his 

 gravity, not only illumines them, not only 

 warms them, but he pours forth on all his subtle 

 yet powerful magnetic influences. A new 

 analogy between the members of the solar system 

 is thus introduced. 



And now we pass on to other discoveries, 

 bearing at once and with equal force upon the 

 relations between the various members of the 

 solar system and upon the position which that 

 system occupies in the universe. 



Hitherto we have been considering the teach- 

 ings of the telescope; we have now to consider 

 what we have learned by means of an instrument 

 of yet higher powers. As I shall have to refer 

 very frequently, throughout this volume, to the 

 teachings of the spectroscope, it will be well that 

 I should briefly describe what it is that this 

 instrument really effects. Were I simply to 

 state the results of its use, without describing its 

 real character, many of my readers would be 

 disposed to believe that astronomers are as 

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