SOME SELF-MADE ASTRONOMERS. 343 



tion of the stars, one might calculate the geographical position of the 

 spot where he happened to he. He sought to know why this was so. 

 For this purpose he had to study mathematics from its rudiments, and 

 was thus led up rapidly to spherical astronomy. He had to be con- 

 tinually introducing the elements of the position of the sun and moon 

 into his calculations, taking them from an astronomical calendar. He 

 desired to calculate these elements for himself. He was thus led to 

 study the laws of the motions of the celestial bodies. The net which 

 astronomical science had cast over him was thus wrapping him closer 

 every day, and in less than a year after he had begun his astronomical 

 studies he undertook the computation of the orbit of the comet of 

 1607, a work that involved three hundred pages of calculations, and 

 which a skilled astronomer might regard as the task of a year. He 

 was not a little proud of his calculations when he had completed them, 

 and he determined to make the acquaintance of Olbers, who was prac- 

 ticing medicine in Bremen, and was regarded as the first authority in 

 everything that related to comets. Meeting the famous doctor in the 

 street, he timidly told him he had calculated the orbit of a comet, and 

 asked him to have the kindness to examine his work. Olbers granted 

 the request, supposing that he was about to receive the work of an 

 amateur, whom he must treat politely, for fear of discouraging him. 

 But he was greatly surprised when he examined the calculations, and 

 he immediately wrote to Bessel : " I have read your work on the comet 

 of 1607 with very great pleasure. It gives me a very high idea of 

 your astronomical and mathematical knowledge, and of your skill in 

 the most difficult departments of calculation. If I should criticise you 

 on any point, it would be only on your having given more time and 

 care to the ancient observations than they deserve." If we place this 

 praise of Olbers by the side of the fact that Bessel did not know a 

 word of mathematics or astronomy a year before, or hardly that 

 there was such a thing as the mechanics and mathematics of the 

 sky, and if we also recollect that he was occupied from eight o'clock 

 in the morning till night with something entirely different, we can 

 gain a slight idea of the great energy and the rare mental constancy 

 which he must have displayed, and Avhich afterward carried him 

 so far. 



Bessel's fate was decided. He was recommended by Olbers to 

 Gauss, who, in the same year, invited him to assist him in the calcu- 

 lations with which he was occupied. Bessel accepted the invitation 

 with enthusiasm, and, according to his habit, made the calculations 

 with more precision than was required. From that time Gauss and 

 Bessel were connected in a lasting scientific friendship.- Bessel was to 

 wait another year before giving himself up entirely to astronomy, but 

 early in 1806, warmly supported by Olbers, he was appointed inspector 

 of a private observatory at Lilienthal. He remained there four years, 

 till his reputation brought him a call to the direction of the new ob- 



