CHAPTER IX 



THE SUN 



So carefully and persistently was the sun studied by 

 Herschel that, for the sake of clearness, it is advisable 

 to arrange his work not in the order of time, but 

 according to the subject he treats of. He began at 

 an early period to watch the sun's face, and to make 

 experiments with the view of discovering its history, 

 past and future. Could he but read that history or 

 even a chapter of it, he felt that he would be able to 

 read the history of other suns as well as ours, and 

 perhaps to lay a foundation for fellow-labourers in 

 the same cause to build a temple to science on. He 

 succeeded beyond his wishes, or at least his hopes. 



The first thing he endeavoured to ascertain was, 

 whether the sun was stationary or nearly stationary 

 in the heavens. Astronomers had already discovered 

 that its immense fiery globe had a day like our earth, 

 that is, that it turned round on its axis precisely as 

 the earth does. The time it takes they found to be 

 25 d 7 h 48 m of our reckoning. This is the length of the 

 sun's day. But Herschel asked if the sun had not a 

 year as well as a day, a time vast, immeasurable, 

 perhaps in which it revolves round a centre, hidden 

 from man's knowledge, but not from man's sight, if he 

 only knew where to look for it. Herschel looked for 



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