212 COSMOS. 



two of the smaller principal planets in our solar system, the- 

 eccentricity of the orbit of Pallas being 0*24, and that of 

 Juno, 0*25. 



If, with Encke, we consider one of the two stars in a bi- 

 nary system, the brighter, to be at rest, and on this supposi- 

 tion refer to it the motion of the companion, then it follows 

 from the observations hitherto made that the companion de- 

 scribes round the principal star a conic section, of which the 

 latter is the focus ; namely, an elHpse in which the radius 

 vector of the revolving cosmical body passes over equal su- 

 perficial areas in equal times. Accurate measurements of 

 the angles of position and of distances, adapted to the determ- 

 ination of orbits, have already shown, in a considerable num- 

 ber of double stars, that the companion revolves round the 

 principal star considered as stationary'", impelled by the same 

 gravitating forces which prevail in our own solar system. 

 This firm conviction, which has only been thoroughly attain- 

 ed within the last quarter of a century, marks a great epoch 

 in the history of the development of higher cosmical knowl- 

 edge. Cosmical bodies, to which long use has still preserved 

 the name oi fixed stars, although they are neither riveted 

 to the vault of heaven nor motionless, have been observed 

 to occult each other. The knowledge of the existence of 

 partial systems of independent motion tends the more to en- 

 large our view, by showing that these movements are them- 

 selves subordinate to more general movements animating the 

 regions of space. 



