THE GREAT COMET OF 1*58. 



99 



Systematic error is not quite so manifest here as in the declinations, the observa- 

 tions not agreeing so well among themselves, but it undoubtedly exists in eOMderabl. 

 quantity. The quantity used for the normal of Sept. 17 was — 12".G7, and the orbit 



found g 



13".07 



We shall make one more trial; about Oct. 8, the effect according to the hypoth 



took place wholly 

 stands thus : 



direction of right ascension. The 



of ob 



Ann Arbor. Paris. Berlin. Liverpool. Kbnigsberg. Bonn. Kremsmiinster. 



12.6 



^v . . " " " it U II H 



Oct. 4 —7.20 —2.82 



5 —7.94 .... -f-1.71 .... — 7.91 —7.65 .... 



u •••• •••• — 4.oU .... ••♦. • • • • —11.01 



• •••• m • • • — 4:.J# • • . . •••• •••• — O.UU 



8 .... —2.80 .... —8.49 .... —4.85 — 2.40 



9 —0.09 —4.29 —12.66 



10 _ 6.49 



11 — 4.78 



12 .... 



1" — 1-20 -J-4.11 .... 



14 -f 5.45 _ 3.73 



Pulkova. 



Genera. Greenwich. 



876 



a 



The observations 



are too scattered to establish anything w 



• • 



10.98 



4.17 



• • 



16". 18 



10.96 

 11.00 



8.19 



9.49 



• • 



• • • 



• 



6.94 



o.r.8 



• I 



2.05 



• • 



5.2 

 4.39 



• • 



• • 



th certainty, but the 



systematic errors seem to be larger than before, and, Greenwich excepted, the obser- 

 vations with the small telescopes place the comet farther from the Sun than iho.se 

 with the large telescopes. The same thing is probably true of the observations of the 

 rest of October, but as the northern observations here begin to fail us, we can make 

 no comparison. 



It would be very difficult, perhaps impossible, to arrive at a sitisfactory explanation 

 of these systematic errors and 



undertake any discussion of them. If, however, this hypothesis should be adopted 



to assign their numerical values, consequently I shall 



and 

 obse 



aryino- inversely as the size of the telescope should be applied to the 



_ • A .. Iff A- Off il. _ 



removing the 



from the Sun a space ranging from 1 



3 



With 



effect would be to diminish the period of revolution by about 'lb or 30 years, 

 regard to this, the most interesting element of the orbit, we may state with confidence 

 1 think, that it is not less than 1900 years, and cannot exceed 1975 years. 



