264 POOR 



From the above tables I find directly the total changes in 

 the elements during the interval 1889, Sept. 30.5, to 1886, 

 Oct. 26.5, as follows : 



Afi =z -I- 2o''''.4i57o 

 A7r = -|- 1° 4^ 2^''. 14 

 Ai2^ + I 7 12 .48 



^<P = + 3 43 35 -31 

 A?'=+i 23 I .38 



^A = + 3 3} 54 -38 

 AZu = -i-o 5 27 .60 



In applying JL^ and -/^u, as above given, it must be noted 

 that proper values of fi must be used for the intervals between 

 1889, March and 1887, March; 1887, March and 1886, 

 December; and 1886, December and 1886, October. 



Applying these perturbations to Elements V, and at the 

 same time reducing them to the mean equator and equinox of 

 1886.0, I have for osculating elements, which represent the 

 motion of the comet, at the moment it left Jupiter's "sphere 

 of activity" : 



Epoch, 1886, Oct. 26.5, Greenwich M. T. 

 // =r 522^^.09645 + 0'''.0II4l' 

 Z = 2i5°5i^26'''.92 — 14 .2747!'- 

 '^= 2 35 49 .24— 3 .07671- 

 i2^ 19 2 59 .79 — o .01741^ .18S6.0 

 (pz^ 31 4847 .68 — I .39611^ 

 t=z 7 27 5 .78 — o . 11401^ . 

 il/o = 2i3 1537 .68 — 11 .19801- 



30. Transformation to Jupiter as Ccjiter of Motion. — The 

 general method used, which was first proposed by D'Alembert, 

 consists in supposing the planet to have a "sphere of activity," 

 within which the relative motion of the comet is affected only 

 by the planet's attraction and beyond which the absolute motion 

 of the comet about the sun is performed as if the sun alone 

 acted upon it. The radius of the sphere depends upon the 

 mass of the planet and its distance from the sun. This was the 

 simple method afterwards used by LaPlace and again by Le- 

 Verrier. But while beautiful and simple, it neglects entirely 

 the effect of the sun as disturbing body whilst the comet is 



