468 Proceedings of the Royal Society 
Frederick Gteorge William Struve, a distinguished astronomer, 
was born at Altona, on the 15th April 1793, and was the fourth son 
of Dr Jacob Struve, Director of the Grymnasium, in that city. At 
the University of Dorpat, which he entered in 1808, and where his 
elder brother was classical lecturer, he took the degree of Doctor of 
Philosophy in 1813, and in the following year he was appointed 
Assistant at the Observatory, and Extraordinary Professor of Astro- 
nomy. In 1820, he was chosen Director of the Observatory, an 
office which he held till 1839, when he was called to the direction 
of the great observatory which the Emperor of Eussia had estab- 
lished at Pulkowa, and furnished with the finest instruments. 
Between 1816 and 1819, he executed the trigonometrical survey 
of Livonia. Between 1822 and 1827, he measured a part of the 
meridian in the Baltic provinces; and in 1831 he published an 
account of his operations. In 1828 he connected this survey with 
that of General Tenner ; and in 1851 he completed the measure of 
the Eiisso-Scandinavian arc of the meridian between Ismael, at the 
mouth of the Danube, in 45° 20' and Fuglenaes in 70° 40' of north 
latitude, — an arc of 25° 20', the largest that ever has been measured. 
Among the other scientific expeditions undertaken by M. Struve, 
was the levelling of the country between the Black Sea and the 
Caspian Sea, the determination of the geographical position of 
several points in Siberia, in the Trans-Caucasian provinces and in 
Asiatic Turkey, and the observation of the great eclipses of 1842 and 
1851. The results of these different expeditions have been pub- 
lished in the Memoirs of the Academy of Sciences of St Petersburg. 
During the fifty years spent by M. Struve in the observatories of 
Dorpat and Pulkowa, he made many valuable observations on double 
and multiple stars ; on the parallax of the stars, on their distribution 
in space ; on the Milky Way ; and on the motion of the solar system. 
His observations at Dorpat between 1837 and 1839 have been 
published in eight volumes. Those on Double Stars are contained in 
treatises published in 1820, 1827, 1830, 1837, and 1852; and those 
on the Parallax of the Fixed Stars, on the Milky Way, and on 
the Motion of the Solar System in Space, were published in 1847, 
in a very interesting volume, entitled “Etudes d’Astronomie 
Stellaire.” Adopting 0"*209 as the parallax of stars of the first mag- 
nitude, he found that the annual velocity of the solar system round 
