12 SEEING AND NOT SEEING. 



splendour comparable to that of the principal stars in Ursa 

 Major. But how construct a figure with one star? The four 

 other stars, two of which mark the anterior part of the animal's 

 body, and two others the tail, properly so called, are only of 

 the third magnitude : they are marked /3, 7, 5, g. Finally, the 

 stars which define the posterior portion, marked and q on 

 Bayer's chart, are only of the fourth magnitude in other 

 words, are scarcely visible. The eye, to detect them, must be 

 wholly free from any gleam of light. 



Many generations passed before they succeeded in discover- 

 ing what a single individual solved during his brief career. 

 All Homer's contemporaries, and, prior to these, tens of 

 millions of mortals, had contemplated the sky, and yet none 

 of them had detected the difference between Ursa Major 

 and Ursa Minor. The distinction, therefore, is of a com- 

 paratively recent date; probably does not date back earlier 

 than the sixth century before the Christian era, 



Let us recall ourselves, now, to the question propounded. 

 The first impression produced by the aspect of the sky during 

 a beautiful winter night is, we repeat, that the number of the 

 stars is infinite. This wholly spontaneous thought, which, to 

 some extent, imposes itself on the mind long before the reason 

 attempts any calculation, is, strange to say, both false and true. 



But how can a thought be both false and true ? Nothing is 

 easier than to explain the seeming contradiction. We shall 

 return to it hereafter, after we have indulged in some indis- 

 pensable digressions. 



