ZONE OF PLANETS BETWEEN MARS AND JUPITER. 69 



ished to the twelfth magnitude, while the star of com- 

 parison exhibited no perceptible change. Differences to 

 a greater amount were observed between the 22d and 

 25th of February, 1851. On the nights of the 1st and 

 2d of March, 1851, it appeared as a star of the twelfth 

 magnitude, and was observed without difficulty ; the star 

 of comparison being near, and of about the same magni- 

 tude. On the night of the 3d, Clio could barely be ob- 

 served with the faintest illumination, while the same star 

 of comparison used on the nights of the 1st and 2d ap- 

 peared as before. On the night of the 4th the planet 

 appeared even more brilliant than it did on the nights 

 of the 1st and 2d instant. These changes seem to sug- 

 gest the probability that the light is reflected with un- 

 equal intensity from different sides of this asteroid. 

 Similar differences of magnitude in the other asteroids 

 have been noticed, particularly in Astraea. 



The discovery of Victoria was soon followed by that 

 of another asteroid by Dr. Annibal de Gasparis, at the 

 royal observatory, Naples. In this case a star map was 

 not the means of discovering the planet, but its existence 

 was indicated by a series of observations in zones of de- 

 clination, which had been undertaken for the express 

 purpose of finding new planets. On the 2d of Novem- 

 ber, 1850, Dr. Gasparis met with the thirteenth asteroid 

 in the constellation Cetus. It was sensibly fainter than 

 stars of the ninth magnitude. M. Le Yerrier, to whom 

 was delegated the right of naming this planet, proposed 

 Egeria, the counselor of Numa Pompilius. The orbit is 



