What We Learn from the Sun 



in an oscillatory manner. And when the charac- 

 ter of this vibration came to be carefully ex- 

 amined, it was found to correspond to a sort of 

 effort on the needle's part to turn toward the 

 sun. For example, when the sun is on the mag- 

 netic meridian, the needle has its mean position. 

 This happens twice in the day, once when the 

 sun is above the horizon, and once when he is 

 below it. Again, when the sun is midway be- 

 tween these two positions which also happens 

 twice in the day the needle has its mean posi- 

 tion, because the northern and the southern 

 ends make equal efforts, so to speak, to direct 

 themselves toward the sun. Four times a day, 

 then, the needle has its mean position, or is 

 directed toward the magnetic meridian. But 

 when the sun is not in one of the four positions 

 considered, that end of the needle which is near- 

 est to him is slightly turned away from its mean 

 position, toward him. The change of position 

 is very minute, and only the exact methods of 

 observation made use of in the present age would 

 have sufficed to reveal it. There it is, however, 

 and this minute and seemingly unimportant 

 peculiarity has been found to be full of meaning. 

 Had science merely measured this minute 

 variation, the work would have given striking 

 evidence of the exact spirit in which men of our 

 day deal with natural phenomena. But science 

 was to do much more. The variations of this 

 minute variation were to be inquired into; their 

 period was to be searched for ; the laws by which 

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