42 



vast designs, slowly but steadily progressing towards their accom- 

 plishment. Should the investigation of the parallax of a Centaun, 

 which Mr Henderson gave to the world, turn out correct, of which 

 there is, at present, little doubt, then shall we claim for him the dis- 

 tinction which I have marked with honour — the distinction of having 

 extended astronomical measures beyond the limits of our system.* 

 Nor will it diminish his fame that a similar determination was at- 

 tempted before, or that an equally successful one was nearly contem- 

 poraneous with his own. In few cases has an individual made a 

 successful essay, without having been preceded by others, not des- 

 tined to reach the goal, or accompanied by some one, to share the 

 honour. Thei'e is i-eason to fear, that, in the present instance, 

 whatever honour is due will fall to the lot of another. It is to be 

 regretted, that (whether the conclusion shall ultimately be verified 

 or not) no scientific award was made him, in consideration for the 

 skill displayed ; whilst his contemporary received for his labours a 

 medal from this country. Let us hope that his reward will be the 

 association of his name with the discovery. 



There is another point wherein, as Mr Henderson's advocate, I 



*" On this subject I beg to refer to my friend Mr Main's admirable 

 memoir in the Transactions of the Astronomkcil Socic'ti/, v. . It 



may be interesting to add the following remarks from a private com- 

 munication of his to myself: — "At the time when I was requested to 

 draw up a memoir on the subject of annual parallax, the amount of evi- 

 dence of its sensible existence for any star whatever, which had even 

 arisen from the discussion of investigations previous to Bessel's, was 

 exceedingly small ; and I believe that, at that time, any new attempt 

 was likely to be received with the smile of incredulitj', which repeated 

 failures will always, in the long-run, tend to produce. No sensation was 

 caused in England bj' the announcement of Bessel's investigation ; and I 

 remember that, to some astronomers, his confidence in the certainty of 

 his result seemed far from warranted. At presert there exists verj' 

 little scepticism with respect to our knowledge of the parallax of 

 61 Cygni. But it was deduced by a method with which English astro- 

 nomers were, I may assert, in general, unfamiliar^ perhaps through the 



want of a good heliometer It was an evidence of very 



creditable faith, therefore, which induced Mr Henderson, in default of 

 other means, to attack this star rigorously by meridian observations in 

 both elements, and this notwithstanding his accurate knowledge (for no 

 man living excelled him in his knowledge of every thing that had been 

 done in every department of modern practical astronomy, from its com- 

 mencement) of that total failure of every attempt that had been made 

 under the ablest astronomers of this country, in the northern hemisphere. 

 And so fully was he impressed with the conviction of his ultimate suc- 

 cess, that he left it as a legacy to his successor, who has sent over a very 

 complete and beautiful series of observations, which, after their discus- 

 sion by Mr Henderson himself, not long before his decease, has, in the 

 minds of many, pretty nearly decided affirmatively the question of the 

 existence of a considerable parallax." 



