MARS PLANETOIDS JUPITER SATURN URANUS NEPTUNE. 9 1 



chiefly make their way through the resisting medium. The idea of Sir John Herschel is 

 however more probable, that the fiery aspect of Mars proceeds from the geology of the 



planet, its general soil having this colour, like the 

 red-sandstone districts of the earth, but in a more 

 decided manner. When viewed through a tele 

 scope, the surface exhibits a variety of spots, of 

 which, as observed by Cassini, Hook, and Maraldi, 

 we have several drawings. Some of the spots are 

 changing and evanescent, and appear to be clouds 

 and vapours floating in the atmosphere; but others 

 are permanent, and are evidently geographical 

 features of the planet continents, seas, and 

 regions of polar snow. The annexed view of Mars 

 was taken by Sir John Herschel at Slough, August 

 16th, 1830, in the twenty -feet reflector. The darker 

 parts are seas, which appeared of a greenish hue. 

 The zone observable at the polar point is brilliantly white, but of variable brightness, 

 and is conceived to be snow, its luminosity being least after exposure to the sun through 

 the summer season of the planet, and greatest after the darkness of its long wintry night. 

 There are thus points of striking accordance between the Martial and Terrene worlds. 



I Their periods of light and darkness, night and day, are 

 nearly equal. Both have a succession of seasons, arising 

 j from the obliquity of their respective ecliptics, though 

 of different duration. Both have an atmosphere 

 clouds, rain, snow^ continents and seas ; but without 

 (an attendant moon, the oceans of Mars must be 

 nearly tideless, only gently undulating like the waters 

 of the Mediterranean and the Baltic. Each planet 

 has also vast fields of ice and snow at its poles. 

 Should the inhabitants of Mars take a view of our 

 world through any far-seeing instrument like that 

 with which we inspect their dwelling, the terrestrial 

 aspect, viewed from that distance, in one of its phases 

 will not be very remote from the sketch now given. 

 Proceeding farther on an outward-bound course through the system, we arrive at the 

 cluster of diminutive bodies, whose existence is a modern discovery. They present a 

 variety of anomalies which distinguish them from the older planets ; and received from 

 Herschel the distinctive appellation of Asteroids, a Greek compound signifying the 

 appearance of stars, but by others they are more properly called Planetoids, or small 

 planets. Of these bodies, now (August 1858) fifty-three in number, four were discovered 

 early in the century, Ceres, Pallas, Juno, and Vesta, as the result of a search conducted upon 

 the presumption that some unknown orb lurked in the vast space between Mars and Jupiter. 

 The first three are exclusively telescopic objects, and require the best instruments to be 

 caught. But Vesta shines with a very intense light, as a brilliant point in the heavens, 

 and has been observed on a clear evening by the naked eye. Following the order of 

 succession in the system, Vesta is at the mean distance of 225 millions of miles 

 from the sun, Juno 254, Ceres and Pallas 263. Their periods of revolution range from 

 somewhat more than 3| to 4| years. The orbit of Juno is remarkable for its eccentricity, 

 being so elliptical that the greatest distance of this minute world from the sun is nearly 

 double the least. Both Ceres and Pallas appear to be surrounded with a nebulous haze. 



