100 
yielded the epochs of eight maxima, or double the number 
observed by Schonfeld, thus enabling me to determine with 
greater exactness the length of the mean period. These 
maxima are as follows : — 
1861, October 16 
8*7 
mag. 
1862, November 21 
8*9 
1864, January 8 
9*3 
„ August 20 
8*7 
?? 
1865, March 9 
8*4 
5? 
,, October 1 
8*7 
JJ 
1866, April 19 
8-2 
JJ 
„ November 14 
9*0 
» 
Equating, and treating by the method of least squares, 
we have 
Mean period = 206*8 days. 
Mean epoch = 1864, August 10*7. 
Calculating from these elements we find that a maximum 
ought to have occurred 1832, November 25, or 42 days 
earlier than Bessel’s observation. As this difference con- 
siderably exceeds any that could be due to the form of the 
light curve at its maximum, it seems probable that the 
length of the period has slightly increased since the date of 
Bessel’s observation. 
The differences between the observed and the calculated 
times of maxima are: 
Observed — Calculated. 
+ 4*7 days 
—7-9 
—8*5 
+ 9*7 
>5 
J) 
J5 
Observed — Calculated. 
+ 3*9 days 
+ 3‘1 J 
-3'7 „ 
—1-5 „ 
The mean magnitude of the star at maximum appears 
from my observations to be 8*7. The magnitude at mini- 
mum is generally below 13. 
