VARIABLE STAR R VULPECUL^E. 271 



Maxima. Minima. 



1861. Dee. 30"o, 8*4 mag. 1861. Oct. 26-3, i3"6 mag. 



1862. Oct. 5.0, 7-8 ,, 1863. Sept. i8*o, i3'2 „ 

 *i863. Not. I9'4, 7-6 ,, 1864. June 19-5, 13*2 ,, 



1864, Aug. i6'3, 7-5 ,, Not. 4*0, i3"i „ 



1865. Jan. 7'3, 77 „ 1865. Aug. 6-3, 12-8 „ 



25'5, 7'8 „ Dec. i4'3, 137 „ 



Oct. 5-5, 7-5 „ 



Treating the seven observed maxima according to Mr. 

 BaxendelFs method^ we obtain tbe following elements :- — 



Period= 137-59 days. 

 Epoch = 1864, April 4'95. 



Comparing tbe observed times of maximum with those 

 calculated from these elements, and also from those of Dr. 

 Winnecke, we obtain the following differences between 

 calculation and observation : — 



Knott's Elements. 



Winnecke's Elements, 



Calc.-Obs. 



Calc.-Obs. 



days. 



days. 



+ i"4i 



-3-2 ' 



— 2-41 



-5-0 



— O'OI 



+ 0-4 



+4-24 



+ 7-1 



— 2'23 



+ 1-3 



-2-78 



+ 1-7 



+ i-8i 



+ 7-3 



the sums of the squares of these numbers being 43*75 and 

 143*78 respectively. But while it thus appears that my 

 own observations accord moderately well with Dr. Win- 

 necke's elements^ it must be confessed that these latter 

 represent more satisfactorily than my own (as indeed might 

 be expected) the magnitude-estimates of Piazzi in the year 

 1807 and 1 8 10, as given by Dr. Winnecke in No. 1224 of 

 the 'Astronomische Nachrichten.' At the same time it 

 must be remembered that my own elements were deduced 



* The projection of a series of his own obserTations of this maximum 

 obligingly communicated to me by Mr. Bajendell, yields the following re- 

 sults, in gratifying accordance with my own : — Date of maximum, 1863, 

 Not. i8'9, mag. y$. 



