134 Double Stars. 



and 33 Orionis, neither exceeding 2" in distance., as a test for a 

 superior instrument ; its movement during* the present century 

 has been such as to indicate, in Struve' s opinion, a sidereal occul- 

 tation between 1802 and 1819, when its distance was 1"*5, with 

 the smaller star on the other side. The same observer thought 

 it was approaching its greatest distance in 1835, when it 

 measured 3"'17; but Secchi found it 4"-738, 1859-515. The 

 ellipse in which it is moving is probably foreshortened almost 

 into a straight line. Secchi, between 1855 and 1859, thought 

 the brightness reversed, so that there may be a variation of 

 light, which was also the opinionof Struve and Argelander. 



Retracing our path a little from this object towards the 

 hand of Bootes, but keeping somewhat below our guiding line, 

 we find a very minute star, which the telescope expands into a 

 beautiful pair — 



34. 39 Bootis. 3"-8. 44°- 7. 5| and 6|. White and lilac. 

 Some observers ascribe a bluish, some a ruddy tint, to the small 

 star. Struve considered them to be probably moving, but 

 Smyth and Secchi doubt this. I thought in 1850 that the dif- 

 ference in magnitude was less than that assigned by Smyth in 

 1839. Secchi gave them 6 and 6*5 in 1856 ; 6 and 6'2, 1857 : 

 perhaps there may be variable light here. 



We now proceed to Corona Borealis, the Northern Crown, a 

 beautiful little constellation, the principal part of which is well 

 marked out by an ellipse of 4 and 6 mag. stars, among which 

 is one of 2 mag. (a), lying in a line between Arcturus and $ 

 Herculis (No. 25). A line drawn from Arcturus through e (No. 

 19) and h (No. 23) Bootis, bent a little to the left, will fall upon — 



35. % Coronal. 6"'l. 301° - 2. 5 and 6. Flushed white and 

 bluish green. This truly fine pair, notwithstanding its aspect, 

 is very satisfactorily shown to be stationary, as far as our pre- 

 sent evidence extends. 



Our next object is found by a more complicated process. We 

 draw a line from Wega to a Corona 3 , : this passes, at about three- 

 fifths of the distance, a little above £ Herculis, 3 mag., the bright- 

 est star in the vicinity. Another line from % Herculis to £ Coronas 

 (our last object), at about one-fourth of the distance, falls upon — 



36. v x and v z Coronas, a noble 5 mag. pair of yellow stars,rather 

 more than 6' apart, to each of which an aperture of 5^ inches 

 shows a minute attendant. A low power includes another star of 

 about 6 mag., forming a splendid field. A little way (2°)p lies — 



37. a Coronas. l"-3. 107°-6 (1830-76). 2"-2. 176 3 -8 

 (1852-25). 6 and 6|. Creamy-white and smalt-blue. There 

 is much discrepancy about the smaller star. South calls it 

 <( certainly not blue," and differing very little from the other, 

 1825; Struve, white, 1836*69; Dembowski, yellow,, ashy, and 

 doubtful blue, 1854 to 1857 ; Secchi, sometimes blue, sometimes 



