PORTION OP THE COSMOS. THE PLANETS. 389 



move from west to east, and all, excepting some of the 

 asteroids, have orbits but little inclined to the ecliptic, the 

 almost perfectly circular path of the satellites of Uranus is 

 inclined to the ecliptic at an angle of 78 58', being there- 

 fore nearly perpendicular to it ; and the satellites themselves 

 move from east to west. In the satellites of Uranus, as well 

 as in those of Saturn, the sequence or arrangement of the 

 nomenclature, 1st, 2d, 3d, &c., taken from their respective 

 distances from the primary planet, is altogether distinct from 

 the sequence of the epochs of their discovery. Of the satel- 

 lites of Uranus, those first discovered were the 2d and the 

 4th, by William Herschel, in 1787; then, in 1790, the 1st 

 and the 5th ; and lastly, in 1794, the 6th and the 3d, all 

 by the same astronomer. In the course of the fifty-six 

 years which have elapsed since the latest discovery (that of 

 the 3d satellite), the existence of so many as six satellites 

 has been often, but unduly doubted ; the observations of the 

 last twenty years have gradually shewn how much confidence 

 may be placed in the great discoverer of Slough in this de- 

 partment of planetary astronomy also. Hitherto the satel- 

 lites of Uranus which have been seen again are the 1st, 2d, 

 4th, and 6th; to which may perhaps be added the 3d, 

 according to LasselTs observation of the tJth" of November, 

 1848. On account of the large aperture of his reflector, 

 and the abundance of light obtained thereby, the elder 

 Herschel, with his acute vision, considered a magnifying 

 power of 157 sufficient under favourable atmospheric cir- 

 cumstances ; his son prescribes generally for these exceed- 

 ingly small luminous disks a magnifying power of 300. The 

 2d and 4th satellites are those which have been seen again 

 earliest, most certainly, and most frequently ; in Europe 



