GALILEO AND HIS JUDGES. 67 



they called it). At so great a distance as that, 

 the change of position caused by the Earth's annual 

 motion round the Sun would not be appreciable. 



The principle of this reply is of course quite sound, 

 and we, who know the stars to be considerably farther 

 from us than the above estimate supposes, can. well 

 understand that the vast majority of them have no 

 annual parallax whatever, that the finest instruments 

 can discover. 



To further objections drawn from the enormous 

 distances of the stars, and the difficulty of perceiving 

 the use which such remote bodies can be to the 

 Earth, it is replied that such speculations are useless 

 and presumptuous, and also that words like small, 

 very small, immense, etc., are relative rather than 

 absolute. 



Some pains are taken in the course of the dialogue 

 to explain how the stars, according to their different 

 positions, would be affected by annual parallax, 

 supposing such to be discoverable, and assuming the 

 motion of the Earth. And a minute explanation is 

 also given, on this latter assumption, of the length 

 of day and night varying in different latitudes 

 according to the seasons ; illustrating the fact that 

 details which appear to us elementary and are 

 taught to schoolboys, were strange to the minds 

 even of educated and learned men in those days. 



One remark, arising from the questions connected 

 with stellar parallax, is most striking, as showing how 

 far Galileo was advanced in his knowledge of pure 



F 2 



