W1 
was communicated to the Section on the 12th of November, 
1863, and printed in the third volume of the Society’s 
Proceedings. At that time I had observed only one mini- 
mum and one maximum, and was therefore unable to deter- 
mine, with any near approach to accuracy, the length of the 
mean period and the mean range of variation of magnitude. 
I have however since observed eight additional minima and 
eight maxima thus making a total of nine minima and 
nine maxima, which from the length of time over which the 
observations extend afford the means of determining the 
mean period and the mean epochs of minimum and maximum 
with considerable accuracy. 
OBSEEYED MINIMA OF T AQUILA5. 
Mag, 
Days in 
Interval. 
Number 
of Periods. 
1863. Aug. 24 
11-3 
1864. June 24 
11-2 
305 
2 
1865. Aug. 31 
11-5 
433 
3 
1866. June 10 
10-8 
283 
2 
Nov, 14 
11-0 
157 
1 
1867. Sept. 12 
10-8 
302 
2 
1868. June 23 
10-7 
285 
2 
1878. Nov. 18 
10-8 
3800 
26 
1879. Oct, 2 
11-6 
318 
2 
Forming the usual equations and treating by the method 
of least squares we obtain 
Mean Epoch = 1868, November, 16'38. 
Mean Period = 146'671 days. 
OBSERVED MAXIMA OF T AQFILiE. 
Mag. 
Day.s in 
Interval. 
Number 
of Periods. 
1863. Oct, 25 
8-9 
. . . 
1861. Aug. 23 
8-4 
303 
2 
1865. June 30 
10-1 
311 
2 
Nov. 22 
9-4 
145 
1 
1866. Sept. 6 
8-7 
288 
2 
1867. Nov. 4 
9-0 
424 
3 
1868. Aug 15 
9-0 
285 
2 
1878. Sept. 15 
9-0 
3683 
25 
1879. Nov. 22 
9-1 
433 
3 
/6 
