XXI 



work it is incidentally noticed that on one occasion lie had observed unin- 

 terruptedly for eight hours in a temperature of 25 C.], " Stellarum 

 duplicium et multiplicium mensurse micrometricae, 1 837," " Stellarum 

 fixarum imprimis compositarum positiones mediae, deductae observatioiiibus 

 meridianis a 1822 ad 1843 in specula Dorpatensi, 1852," " Beobachtungen 

 des Halley'schen Cometen bei seinem Erscheinen im Jahre 1835, auf der 

 Dorpater Sternwarte angestellt, 1839." 



In the spring of 1839 he left Dorpat to assume the Directorship of the 

 Observatory of Pulkowa, built in accordance with his own plans, and fur- 

 nished with instruments contrived and executed under his own directions. 

 An account of the building and instruments is given in his " Description de 

 1'Observatoire central de Pulkowa, 1845." In 1843 he published his 

 " Catalogue de 514 etoiles doubles et multiples, &c., et Catalogue de 256 

 etoiles doubles principales ou la distance des composantes est de 32" a 

 2' &c.," and " Sur le coefficient constant dans 1'aberration des etoiles fixes 

 deduit des observations qui ont etd executees a 1'observatoire de Poulkova." 

 In 1847 he published " Etudes d' Astronomic stellaire." 



Struve devoted a portion of the summer for many years to the vast un- 

 dertaking of measuring an arc of the meridian of 25 20' from Fuglenaes 

 on the Arctic Ocean, lat. 70 40', to Ismail on the Danube, lat. 45 20'. 

 This work may be considered the principal labour of his life : he 

 was assisted in it by General Tenner and the astronomers Selander and 

 Hansteen. It lasted thirty-seven years, and was completed in 1853 An 

 account of the measurement is given by Struve in " Breitengradmessung in 

 den Ostseeprovinzen Russlands ausgefiihrt und bearbeitet in den Jahren 

 1821 bis 1831," in " Expose* historique des travaux executes jusqu'a la fiu 

 de 1'annee 1851, pour la mesure de Tare du mcridien, &c., 1860," and in 

 "Arc du me'ridien de 25 20' entre le Danube et la mer Glaciale, 1860." 



Besides the works already mentioned, he is the author of many separate 

 treatises, and of papers in Bode's ' Jahrbuch,' the ' Zeitschrift ' of von 

 Lindenau and Bohnenberger, von Zach's ' Correspondence Astronomique,' 

 and the 'Bulletins' and ' Memoires ' of the Imperial Academy of St. 

 Petersburg. 



In 1858 he was attacked by a severe illness, for which rest from work and 

 travelling were prescribed. These remedies, however, failed to remove the 

 consequences of his malady. In 1862 he retired from the post of Director 

 of the Pulkowa Observatory, and was succeeded by his son O. \V. Struve. 

 He then went to live with his family in St. Petersburg, occupying the 

 remainder of his life with the subject of double stars. On the 4th of 

 November he felt Indisposed ; his strength failed rapidly ; and he died on 

 the morning of November the 23rd, 1864. 



He was elected Foreign Member of the Royal Society in 1827, and in 

 the same year one of the Royal Medals was awarded to him for his ' Cata- 

 logus novus Stellarum duplicium.' He received the Gold Medal of the 

 Royal Astronomical Society in 1826, "for his important researches on the 



