282 OUTLINES OF NATURAL PHILOSOPHY. 



i 



Mr BURKHARDT found that the Comet had come so 

 near to Jupiter between 1767 and 1770, that it 

 may have been brought from an orbit of which the 

 semi-transverse was 13.293, (that of the Earth's or- 

 bit being 1), and in which it revolved in a period 

 of 48.466 years, to one in which the semi-trans- 

 verse was 3.178, and in which it revolved in five 

 years and eight months, as it was at that time ob- 

 served to do. While revolving in this orbit, it 

 came near to Jupiter again ; and its time of revo- 

 lution and its distance were so changed, that the 

 latter became 6.388, and the former 16 years. In 

 this orbit it cannot, any more than in its first, 

 come so near the Earth as to be visible. 



The preceding is the greatest instance of disturbance 

 that has yet been discovered among the bodies of 

 our system, and furnishes a very happy and unex- 

 pected application of the theory of Gravitation. 



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281. Though the Comets are disturbed in so 

 great a degree by the action of the Planets, 

 they do not appear by their re-action to pro- 

 duce any sensible effects. 



This must no doubt arise from the small quantity of 

 matter which a Comet contains. 



The Comet of 1770 came so near to the Earth, as to 

 have its periodic time increased by 2.046 days, ac- 

 cording to LA PLACE'S computation, and if it had 

 been* equal in mass to the Earth, it would have 



made 



