590 
Proceedings of the Royal Irish Academy. 
42. Struve 2173 = 221 B Ophiuchi. A complete revolution has 
been described since its discovery by Struve in 1829. Duner's orbit 
seems to be a good one. It represents recent measures satisfactorily. 
Some of tbese are as follows : — 
1882-58 : 109°-9 : 0"-31, ScMaparelli. 
1885-66 : 21 -9 : 0 -30, Engelmann. 
1887-401 : 350 -47 : 0 -46, Tarrant 2898). 
1887- 56 : 348 -5 : 0 -54, Scbiaparelli. 
1888- 49 : 167 '8 : 0 -68, Leavenworth. 
The components are nearly equal in brightness, so that Leaven- 
worth's angle requires a correction of 180.° Variable light was 
suspected by 0. Struve, and Leavenworth's measure seems to favour 
this supposition. 
43. II Herculis. This is the fainter component of the wide double 
star IX Herculis = ^ 2220. The duplicity was detected by Alvan Clark 
in 1856. 
Some recent measures are : — 
1880- 47 : 245°-9 : 0"-96, Burnham. 
1881- 41 : 252 -1 : 0 -92, „ 
1889- 51 : 357 -9 : 0 -55, „ 
44. T Ophiuchi = % 2262. An arc of about 285° of the apparent 
orbit has been described since its discovery by Sir W. Herschel in 
1783, but the motion has been round the periastron of the orbit. The 
angular motion is now becoming slow. Dr. Doberck's elements are 
the best. 
Some recent measures are : — 
1880-55 : 
253°-01 
l"-83, Doberck. 
1882-49 : 
255 -0 
1 
•58, 
1883-38 : 
254 -5 
1 
•84, Engelmann. 
1885-482 : 
258 -05 
1 
•79, Tarrant {A.N., 2866). 
1886-62 : 
256 -2 
: 1 
•85, Jedrzejewicz. 
1887-09 : 
252 -0 
: 1 
•72, Schiaparelli. 
1888-53 : 
254 -7 
1 
•92, Leavenworth. 
A list of measures by Dr. Doberck, from 1876 to 1882, will be 
found in the Transactions of the Eoyal Irish Academy, vol. xxix., 
part XIII. (1890). 
