198 
tained that it is a periodical variable which goes through its 
changes in about seventy-four days, varying from the 9.8 
magnitude at minimum to the 8.4 magnitude at maximum. 
Its mean place for 1860.0, as derived from comparisons with 
two stars which occur in Bessel’s Zone 192, and with the 
stars Nos. 1809 and 1810 of the Greenwich twelve-year 
Catalogue, is R.A. 20h. 7m. 40.1s.; and N.P.D. 73° 41' 
44.5". Its colour, especially when seen during its maximum 
with Mr. Worthington’s large reflector, is a deep orange- 
yellow. 
As this is, so far as I am aware, the first variable yet dis- 
covered in the constellation Sagitta, it will, in conformity 
with Professor Argelander’s system of nomenclature, be 
denoted by the letter R. 
The approximate places, and the magnitudes of the stars 
with which I have compared the variable during its changes, 
are as follows : — 
Mag. 
R.A. 
h. 
1860.0. 
m. B. 
N.P.D. 
0 
1860.0. 
/ 
a 
7.7 
20 
7 37 
73 
33.7 
b 
8.5 
20 
7 17 
73 
51.4 
c 
8.8 
20 
8 30 
73 
39.1 
d 
9.1 
20 
7 32 
73 
29.8 
e 
9.1 
20 
8 1 
73 
40.6 
f 
10.0 
20 
7 15 
73 
41.8 
9 
10.1 
20 
7 58 
73 
48.5 
The magnitudes of these stars were obtained photometri- 
cally by the method of limiting apertures, Mr. Pogson’s 
value (2.512) of the ratio of light for a difference of one 
magnitude being used in the reductions. 
The stars e and c are Nos. 1809 and 1810 of the Green- 
wich twelve-year Catalogue above alluded to, and I may 
here remark that there is now no star visible on the place of 
No. 1811 of this Catalogue. As however there is a 9^ mag- 
nitude star about 1' 28" distant to the south, it might be 
