WHEN IS THE SUN NEAREST EARTH 1 } 295 



least heat, than at that period of the year when its vivifying 

 power is greatest ? I think it is obvious that, to the unex- 

 perienced, such a method of explaining the cold of winter 

 and the heat of summer by the variation in the distance of 

 our great solar luminary would naturally occur. 



But the demon of certainty an excellent demon, whatever 

 the orthodox may say is present, to stimulate us all. You 

 may have just formed your theories, you may cite your tradi 

 tional authorities, but these will not satisfy our awakened 

 curiosity. We ask for demonstrations, for irrefragable proofs 

 drawn from the Bible of Nature. We will listen to no oracles 

 but those which are confirmed by the voices of God's second 

 revelation. 



Therefore, men required to be assured that the sun was really 

 nearer to us in summer than in winter. For this purpose, it 

 was requisite to make, at the beginning of summer, an observa- 

 tion analogous to that which had been made at the beginning 

 of winter, and afterwards to compare the apparent magnitudes 

 of the solar disc at these two opposite periods of the year. 



Behold us, then, at work. You are perfectly tranquil as to 

 the result; for you are persuaded beforehand that the sun must 

 be farther from us in the cold season than in the hot. You 

 regard this as a self-evident truth, like an axiom of Euclid's. 



But Nature is a great magician; she contrives the most 

 dramatic surprises for the mind which takes the trouble to inter- 

 rogate her in all simplicity and without dogmatic pretensions. 



What a coup-de-theatre it was for the observer who first 

 established experimentally that the apparent diameter of the 



