1826.] Astronomical Society » 457 



he was the first to discover, and has advanced a theory relative 

 to the system of the universe, which, whether it be reahzed 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 observed 

 by Sir William Herschel in his review of the heavens in 1802 

 and 1804, had determined Mr. Herschel to follow up the inten- 

 tions of his father, by a review of all the double stars inserted 

 in his catalogues : and as early as 1816 he had commenced this 

 arduous undertaking. Mr. South also being disposed to pursue 

 the same inquiry, suggested the plan of carrying on their ob- 

 servations in concert : and, with the aid of two excellent 

 achromatic telescopes, belonging to the latter, they employed 

 the years 1821, 1822, and 1823 in this research. The result 

 of their labours was presented to the Royal Society, and pub- 

 lished in the Philosophical Transactions for 1824, at the expense 

 of the Board of Longitude. 



The 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 measurements 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 remarkable phsenomena, 

 first brought to light by Sir William Herschel, have been abun- 

 dantly confirmed ; and many new objects pointed out as worthy 

 the attention of future observers. 



Whilst these important inquiries were carrying on in Eng- 

 land, one of our Associates, Professor Struve, was euoaoed in 

 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 in most of the measurements made by M. Struve, 



* Although not immediately connected with the object of this Address, I cannot 

 omit this opportunity of noticinj; the labours of M. Aiiiici on double stars. With some 

 excellent and beautiful telescopes and micrometers of liis own workiiiansliip and con- 

 struction, this indefatigable and careful observer has extended liis examination to up- 

 wards of 200 double stars ; and has detected motions in some of them, not yet noticed 

 by other astronomers. It is to be hoped tliat Ilia very valuable labours will be collected 

 and published, fur the benefit of science. 



