92 SCENERY OF THE HEAVENS. 



helion, she is nearer the sun by 130 millions of miles than when in her aphelion. Juno 

 shines with a ruddy light of varying brightness, attributed to changes in the density of 

 her atmosphere. Her diameter is estimated by Schroeter at 1425 miles, but this appears 

 to be an excess. Her period of revolution is 4 years and 128 days. CERES, the third in 

 order, was discovered byPiazzi in the constellation Taurus on the 1st of January 1801 at 

 Palermo in Sicily, and was named after the tutelar goddess of the island. The mean 

 distance of this planet from the sun is 263 millions of miles, and her period of revo- 

 lution about 4| years. She is never visible to the naked eye, and when seen through 

 a telescope appears surrounded by a cloudy nebulous light, which gives her the aspect of 

 a comet, and indicates an extensive atmosphere. The determination of the diameter of 

 Ceres by Schroeter is supposed to be too high, and that of Herschel too low. The former 

 is 1624 miles, the latter 170. PALLAS, the last of the asteroids, and the second brought 

 to light, was seized by Olbers on the 28th of March 1802 This body is situated at about 

 the same mean distance as Ceres. Their magnitudes also and periods of revolution are 

 'nearly equal. 



There are several peculiarities belonging to these planets. Though their dimensions 

 are not known with precision, they are undoubtedly very small when compared with the 

 other independent bodies in the system. The volume of Vesta is supposed to be only 

 Tslro~fr tnat f tne eartn > having a surface which is exceeded by the area of some of the 

 European kingdoms. Mrs. Somerville speaks of the diameter of Pallas as not being much 

 more than seventy-nine miles, whose circumference therefore a steam-carriage would 

 traverse in a few hours. Though no great dependence can be placed upon these estimates, 

 yet admitting them to be far too low, the fact remains certain, that the asteroids are far 

 inferior in bulk to the least of the satellites. These bodies are also extra-zodiacal. They 

 deviate considerably from the path in the heavens described by the other planets, so 

 much so, that the zodiac must be expanded nearly five times its breadth in order to include 

 their orbits. Their mean distances from the sun likewise differ very slightly, while their 

 orbits intersect one another, the most remarkable feature of their condition. The 

 paths of Ceres and Pallas cross each other as represented in the diagram, while that of 



Vesta cuts the other three. These are peculiarities 



altogether without example in the system. Immense 

 intervals separate the orbits of the other planets, so 

 that there is no possibility of intersection or collision 

 without an entire derangement of the constitution of 

 the solar universe. But interlacing periodically hap- 

 pens with reference to the paths of these four bodies ; 

 and it is within the limits of possibility for collision 

 to occur by the accumulation of ordinary planetary 

 disturbances. It is also a remarkable circumstance, 

 that in the case of the old planets, traces of atmospheres 

 are only to be discovered by the most subtle observa- 

 tions ; while on the contrary, in the case of the asteroids, 

 excepting Vesta, the atmospherical phenomena appear developed upon an immense scale. 

 The preceding facts led Olbers to the bold conjecture, that these four bodies were 

 originally united, and formed one great planet, which was splintered into fragments by 

 some explosion or concussion. We know that the projections of lava, stones, and torrents 

 of cinders, are with us the common results of powerful subterraneous action; and it has 

 been conceived that if we had no safety-valves in the volcanic craters affording a partial 

 vent if the crust of the globe was without any fissure it could not ultmately resist 

 the increasing force of chemical phenomena developed within its bowels, but some 



