48 LIGHT SCIENCE FOR LEISURE HOURS. 



couragement and authority of his former teacher to 

 prosecute his researches to the end towards which they 

 already seemed to point. Gauss, in reply, not only 

 encouraged Encke to proceed, but counselled him as 

 to the course he should pursue. The result we all 

 know. Encke showed conclusively that the newly- 

 discovered comet travels in a path of short period, and 

 that it had already made its appearance several times 

 in our neighbourhood. 



From the date of this discovery, Encke took high 

 rank among the astronomers of Europe. His subse- 

 quent labours by no means fell short of the promise 

 which this, his first notable achievement, had afforded. 

 If he effected less as an astronomical observer than 

 many of his contemporaries, he was surpassed by few 

 as a manipulator of those abstruse formulae by which 

 the planetary perturbations are calculated. It was to 

 the confidence engendered by this skill that we owe his 

 celebrated discovery of the acceleration of the motion 

 of the comet mentioned above. Assured that he had 

 rightly estimated the disturbances to which the comet 

 is subjected, he was able to pronounce confidently that 

 some cause continually (though all but imperceptibly) 

 impedes the passage of this body through space, and so 

 by one of those strange relations which the student 

 of astronomy is familiar with the continually retarded 

 comet travels ever more swiftly along a continually 

 diminishing orbit. 



Bruhns' Life of Encke is well worth reading, not 

 only by those who are interested in Encke's fame and 



