And its Companion Stars. 129 



Dec. 23rc/,. — " y about 2' off, a completely in the large 

 star but unmistakable, ^ suspected {fig. 1), and seen by 

 Mr. Ellery. 



" Spectv'iiin very unsteady. OF (x very marked, especially 

 F G. Cannot see any other lines at all." 



The remaining observations have been made by Mac- 

 george with the great speculum repolished by Le Sueur. 



After some observations of the spectrum (on several 

 evenings) of Sirius, the following notes of faint stars 

 surrounding Sirius were made (9tli Dec. 1870), "Calling 

 distance from Sirius to companion =10, (fig. 2) 20 mag. 15 

 parts distance from S and making augle 5° with line joining 

 S and its companion preceding d ; another star, 20 mag. 

 about 30° following same line, about 4 parts dist. ft'om d ; 

 ver}^ difficult with power 880 ; definition indifferent. 



On ,fan. 7th, 1871, is noted : " Still see supposed Lassel's 

 companion detected last night ; it is about 12" following 

 (fig. 3), and as nearly as possible at right angle with former 

 supposed Companion (y of Le Sueur) ; best with lowest 

 power ; but no changes of eye-piece affect the observation." 



On 9th January. — "On comparing my observations of 

 Siiius with Le Sueur's I see that he made Lassell's com- 

 panion in the same position as I did on Saturday, so there 

 can be little doubt of it. I had, until this morning, the 

 impression that Le Sueur had not been able to detect 

 l^assell's companion, having missed the entry refemng to it. 

 I see that he imagined he saw another small star (fi) in rays 

 on other side of Sirius {fig. 4). It is singular that I also 

 had this impression once or twice, but concluded I was mis- 

 taken upon re-examination, blaming the eye-piece for the 

 appearance." 



Jan. IMh. — Sirius, splendid definition, no more to be 

 desired ; position of Lassell's companion as sketched making 

 angle between a and y = 93°±, and 12"+, distant fi-om Sirius 

 a {fig. 5 ). These positions are estimated only, as there is too 

 much wind for micrometer work. The companion is blue 

 apparently, and very steady and distinct. 



Could not see Le Sueur's supposed /?, which I also at first 

 imagined I saw. The definition is so good that I am sure 

 both he and I must have been mistaken. Sometimes I 

 imagine to night that I see a very faint star in direction of 

 Le Sueur's y ; but I generally find that a ray points in that 

 dii'ection, which may deceive the eye. Cleared a little again 

 12.30, and I tried the small equatorial on Sirius ; the colour 



K 



