326 On the Orlit of Part of the Leonid Stream. 



Table IV. 



1> 0. 



/ 



a . 



d'. 



i T,' 



! 



B'. 



T 

 JU. 



B. 



W Xi. 



1 



1 AQ° A' 



+ 22° 



2 





+ 8 



54 



14U> ol 



+ 15 



22 



U O 



o 

 £l 



lOJ. UD 



22 



6 



l^bU o 



9 



53 



1 1' 7 <^d. 



17 



3 



1 U 



q 



10U O / 



21 



22 



1 A,^ 1 1 



i^o 11 



8' 



46 



1 A(K 1 9 

 l*tO 1Z 



15 



6 



U O 



** 



1^ 



23 



51 



1 ASK A 



30 



38 



1 zL9 31 

 1*2 ol 



18 



22 



U o 



K 

 O 



lOJ. JLO 



22 



21 



1 AK 99 



9 



53 



1 A(K Qfi 



17 



4 



A 'A 



6 



151 26 



21 



43 



145 47 



9 



21 



147 23 



16 



9 



0-3 



7 



150 19 



19 



47 



145 29 



7 



11 



146 50 



12 



24 



0-2 



8 



149 48 



22 



2 



144 14 



9 



8 



144 37 



15 



47 



0*6 



9 



148 23 



20 



11 



143 38 



6 



56 



143 36 



11 



59 



o-i 



10 



149 52 



20 



41 



144 46 



7 



53 



145 32 



13 



37 



0*3 



11 



149 43 



21 



21 



144 24 



8 



28 



144 50 



14 



38 



0-3 



12 



151 8 



22 



7 



145 23 



9 



38 



146 37 



16 



38 



0-2 



13 



151 42 



22 



7 



145 52 



9 



50 



147 26 



16 



53 



0-5 



columns are given the longitude (L) and latitude (B), of the true 

 radiant corrected for the effect of the earth's orbital motion. 



The quantities L and B define the direction of the tangent to the 

 orbit of the meteors at the point where the earth intersects it, and 

 from the mean of these separate determinations, the position of the 

 earth in its orbit at the time, and an assumption with regard to the 

 period of the meteor stream, the orbit is to be determined.* 



The only difficulty lies in deciding on the best mode of combining 

 the various observations, or in laying down a rule for determining the 

 weights. In this part of the work a certain amount of arbitrariness 

 is, I think, unavoidable. From a careful consideration of all the cir- 

 cumstances of each case, as far as they are recorded, the experience or 

 inexperience of the observer in this class of work as far as it is stated, 

 the number of meteors observed, and the size of the area from which 

 the meteors appeared to radiate, I have been led to adopt the weights 

 given in the last column of Table IV, which represents, I think very 

 fairly, the relative value of the individual observations. It will be 

 noticed that I have given the two photographic results (Nos. 2 and 13) 

 an importance out of all proportion to the number of trails photo- 

 graphed, viz., four trails in the case of No. 2, and two trails in the 

 case of No. 13. This is, I think, justified by the superior accuracy of 

 photographic results in this class of observations. 



I thus find as the definitive position of the radiant of the Leonid 

 meteors of 1898, 



145° 49'±20'-5; +16° 2'±19'*9, 



corresponding to thu epoch November 14*864 (astronomical time). 



* See ' Handworterbucli der Astronomie,' heransgegeben von Dr. W. Yalentiner, 

 vol. 2, Breslau, 1898. 



