110 
yet been published, and I have therefore thought it might be 
desirable to communicate to the Section the results of two 
series of observations which I have made at Mr. Worthington’s 
observatory, and which have enabled me to determine its 
approximate mean period and epoch of maximum. The first 
series commenced on the 26th of May, and ended on the 31st 
of October, 1864. A projection of the observations shows 
that a maximum occurred on the 12th of August, 1864, the 
magnitude being 6*7. The second series began on the 2nd 
of April and was continued till the 12th of November, 1865, 
the star during this time rising from the l T9 magnitude on 
April 2nd to a maximum, 6*6 magnitude, on July 17th, and 
afterwards declining to the 8'6 magnitude on November 12th. 
An inspection of the light-curves which accompany this note 
will show that only one period could have elapsed between 
the dates of these two maxima ; and as Dr. Hencke’s obser- 
vations in 1860 indicate that a maximum occurred about the 
1st of September in that year, we have the following data for 
the determination of the star’s elements : — 
OBSERVED INTERVAL NUMBER OF 
MAXIMA. IN DAYS. PERIODS. 
1860. September 1 1441 4 
1864. August 12 339 1 
1865. July 17 
Equating, and treating by the method of least squares, we 
have 
Mean Period = 357*2 days. 
Epoch of Maximum = 1863, August 10*6. 
The times of maxima calculated from these elements, 
compared with the observed times, give the following differ- 
ences : — 
C-0 
4- 2*0 
- 10*2 
+ 8*0 
