114 ON COMETS. 



Halley was right in his conjecture about Jupiter, and 

 that in fact the return of the comet would be delayed by 

 the attraction of that planet 518 days, and by that of 

 Saturn 100 more, and that it would make its next closest 

 approach to the sun within a month one way or another 

 of the i3th of April 1759. 



(24.) All the astronomers of Europe were looking out 

 for it, eager to seize it on its first coming within the range 

 of human vision. They were all disappointed of their 

 prize. It was carried off by a Saxon farmer of the name 

 of Palitzch, an astronomer of Nature's own creating, 

 who was always watching the heavens, without tele- 

 scopes, without knowledge, simply from the profound 

 interest their aspect inspired him with. He it was who 

 first caught sight of it, on the i3th December 1758. It 

 was taken up by others and regularly observed. It 

 passed its perihelion on the i3th of March, just within 

 the limit of possible uncertainty the mathematicians had 

 allowed for their calculations. 



(25.) This was certainly a very great and signal triumph. 

 It was repeated, with every circumstance that could 

 make it decisive or give it notoriety, in the year 1835, 

 the epoch of the next appearance of " Halley's Comet." 

 The calculation of the planetary perturbations (as the 

 disturbances they cause in each other's motions are 

 called) had then been brought to great perfection. The 

 passage through the perihelion was predicted by M. 

 Pontecoulant to take place on the i2th November, 

 and by Rosenberger between the nth and i6th. In 

 point of fact, it happened on the i5th. And this time, 



