$$ 252, ass] fferschefs Early Life 325 



in using odd fragments of time, such as intervals between 

 the acts at a theatre, for his beloved telescopes. 



A letter written by him in 1783 gives a good account of 

 the spirit in which he was at this time carrying out his 

 astronomical work : 



" I determined to accept nothing on faith, but to see with my 

 own eyes what others had seen before me. ... I finally suc- 

 ceeded in completing a so-called Newtonian instrument, 7 feet 

 in length. From this I advanced to one of 10 feet, and at last 

 to one of 20, for I had fully made up my mind to carry on 

 the improvement of my telescopes as far as it could possibly be 

 done. When I had carefully and thoroughly perfected the great 

 instrument in all its parts, I made systematic use of it in my 

 observations of the heavens, first forming a determination never 

 to pass by any, the smallest, portion of them without due 

 investigation." 



In accordance with this last resolution he executed on 

 four separate occasions, beginning in 1775, each time with 

 an instrument of greater power than on the preceding, a 

 review of the whole heavens, in which everything that 

 appeared in any way remarkable was noticed and if neces- 

 sary more carefully studied. He was thus applying to 

 astronomy methods comparable with those of the naturalist 

 who aims at drawing up a complete list of the flora or 

 fauna of a country hitherto little knowr 



253. In the course of the second of these reviews, made 

 with a telescope of the Newtonian type, 7 feet in length, 

 he made the discovery (March i3th, 1781) which gave him 

 a European reputation and enabled him to abandon music 

 as a profession and to devote the whole of his energies 

 to science. 



" In examining the small stars in the neighbourhood of 

 H Geminorum I perceived one that appeared visibly larger 

 than the rest ; being struck with its uncommon appearance I 

 compared it to H Geminorum and the small star in the quartile 

 between Auriga and Gemini, and finding it so much larger than 

 either of them, I suspected it to be a comet." 



If Herschel's suspicion had been correct the discovery 

 would have been of far less interest than it actually was, 

 for when the new body was further observed and attempts 

 were made to calculate its path, it was found that no 



