126 
Knott’s Elements. 
Calc. — Obs. 
Wxnnecke’s Elements. 
Calc.— Obs. 
Days. 
+ 1*41 
-2*41 
- 0-01 
+ 4*24 
“2*23 
-2*78 
+ 1-81 
Days. 
-3*2 
-5*0 
+ 0*4 
+ 7*1 
+ 1-3 
+ 1-7 
+ 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. Winnecke’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 years 1807 and 1810, 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 solely from my own observa- 
tions, without reference to any of earlier date. 
Treating the six observed minima in the same manner, we 
obtain the following elements, the period presenting a striking 
accordance with that deduced from the observed maxima : — 
Period = 137*55 days. 
Epoch = 1864, June 17*50. 
The differences between the calculated and observed times of 
minima being : — 
Calc. — Obs. 
Days. 
+ 2*35 
— 1*60 
- 2*00 
— 1*95 
-2*15 
+ 5-40 
