THE SUN'S MOTION IN SPACE. 163 



(38) Madler, 18^6. — In 1839 Madler succeeded Friedrich 

 Struve at Dorpat ; the latter having been assigned the directorship 

 of the Pulkova Observatory, then the best organized observatory 

 in the world, and in 1840 he discussed the present state of our 

 knowledge of the System of the Universe, 1 following on in 1846 

 with his own theory of the position of the "central sun," 2 about 

 which our sun and its neighbours were supposed to revolve. The 

 idea was by no means a new one. Long before the architecture 

 of the stars had been systematically studied, Kant, to whose work 

 reference has already been made, had speculated on the possibility 

 of Sirius being the centre of revolution. Lambert, was inclined 

 to regard the vast nebula in Orion as the controlling centre : 

 Herschel the great cluster in Hercules, estimated by him to con- 

 tain 14,000 stars: 3 Argelander selected a point, R.A. = 49° 

 D. = + 54J°, in Perseus : 4 Boguslawski gave preference to Fomal- 

 haut in Piscis Australis. Madler's idea was that the sidereal 

 system revolved about its common centre of inertia, and from the 

 direction and quantity of rotation he concluded that Alcyone 

 {t) Tauri) was, in a passive sense, this centre. The distance thereto 

 he computed to be thirty-four million times the radius of the 

 earth's mean distance from the sun, and the great revolution to 

 be made in 18*2 million years, with a velocity of thirty miles per 

 second. Later Madler published 5 a more complete exposition, 

 which will be more fully referred to hereinafter. 



(39) Mitchell, 18£7.— In 1847 an article by Mitchell appeared 

 on the proper motion of the solar system 6 in the Sidereal Messenger. 



1 TJeber den gegenwartigen standpunkt unseres Kenntniss der Welt- 

 systeme.— Oken, Isis, 1840, pp. 823-835. 



2 Die Central Sonne— Astr. Nach. 566, 567, pp. 213 - 237. Bibl. Univ. 

 Archives in.. 1846, pp. 5 - 29. See also, Uebersicht der neuesten Erweiter- 

 ungen und des gegenwartigen Standes unserer Kenntniss des Sonnen- 

 systems. — Miinchen, Gelehrte Anz. xxu., 1846, pp. 755 - 792. 



3 Phil. Trans. Reprint Vol. xxiv., p. 230, 1806. 

 * Mem. St. Petersb. Acad. t. in., p. 603, 1837. 



5 Die Eigenbewegungen der Fixsterne in ihren Beziehungen zum 

 Gesammtsystem, Dorpat, 1856. 



6 i., 1847, p. 70. 



