Astronomical Society. 297 
nomy. It is true that our late illustrious President has drawn 
some important inferences from those remarkable appearances 
which he was the first to discover, and has advanced a theory 
relative to the system of the universe, which whether it be 
realized or not, (and centuries must elapse before we can even 
approximate towards the truth of it,) must ever show the vigour 
of his bold and comprehensive mind. 
The last production of this Great Man, relative to double 
stars, was communicated to this Society, in the year 1821; and 
is inserted in the first volume of our Memoirs. 
Such was the state of this interesting branch of the science 
at the time it was taken up by Messrs. Herschel and South. 
The singular and extraordinary changes that had been ob- 
served by Sir William Herschel in his review of the heavens 
in 1802 and 1804, had determined Mr. Herschel to follow up 
the intentions of his father, by a review of all the double stars 
inserted in his catalogues: and as early as 1816 he had com- 
menced this arduous undertaking. Mr. South also being dis- 
posed to pursue the same enquiry, suggested the plan of car- 
rying on their observations in concert: and, with the aid of 
tivo excellent achromatic telescopes, belonging to the latter, 
they employed the years 1821, 1822, and 1823 in this re- 
search. The result of their labours was presented to the Royal 
Society, and published in the Philosophical Transactions for 
1824 at the expense of the Board of Longitude. 
he number of double stars observed jointly by these two 
astronomers amounts to 380: and we may judge of their 
value and importance when we learn that the authors were 
more anxious to obtain accurate results, than to extend the 
field of their inquiries in the first instance. But, when we 
find that, even to obtain these results, many thousand mea- 
surements of distance and position were made, we must justly 
admire the patience and perseverance of the authors in this 
their laborious, but highly important pursuit. The remark- 
able phzenomena, first brought to light by Sir William Her- 
schel, have been abundantly confirmed ; and many new ob- 
jects pointed out as worthy the attention of future observers. 
Whilst these important inquiries were carrying on in Eng- 
Jand, one of our Associates, trattstor Struve, was engaged m 
similar observations at Dorpat in Russia. The result of his 
labours is contained in the several volumes of the Observations 
made at that observatory; and will be read with pleasure and 
advantage by every lover of astronomy *, The remarkable 
coincidence 
* Although not immediately connected with the object of this Address, 
I cannot omit this opportunity of noticing the labours of M, Amici on 
Vol. 67. No. 336. April 1826. 2P double 
