308 LIGHT SCIENCE FOR LEISURE HOURS. 



abouts with her direction ; and we can hardly wonder 

 if she does not respond to these solar asides. When- 

 ever the face of the sun turned towards her has shown 

 evidence of perturbation she has responded quickly 

 enough. The disturbance of September, 1859, was 

 answered by movements of the magnetic needle at 

 Kew, which, if not actually simultaneous, were so 

 nearly so that the light of the sun itself reached us no 

 quicker than the influence exciting that magnetic 

 disturbance. Nor did the tremulous response of the 

 perturbed earth last but for a moment. Throughout 

 the night that followed Arctic and Antarctic auroral 

 banners waved over the northern and southern hemi- 

 spheres, being visible in latitudes seldom reached by 

 such displays. For more than twenty-four hours, also, 

 telegraphic communication was interrupted. 



Again, it seems clear that the temperature of the 

 earth, as a whole, is affected by the absence or presence 

 of many spots on the sun's surface. This has been 

 shown apparently in an unmistakable way, by the 

 underground thermometers at Edinburgh and at Green- 

 wich. But the rain and wind cycles, the famine and 

 financial crisis periods, the recurrence of disasters and 

 shipwrecks, bad vine years, and so forth, in harmony 

 with the sun spot waves these have not yet been 

 established. It sounds convincing when one cyclist 

 notes that over a certain region the north-east winds 

 are wetter and the south-west winds drier in sun- 

 spotted times than when the sun is free from spots. 

 Others find it still more convincing when some one 



