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THE MINOR PLANETS.

whole period of the contraction of the Nebula, from which,according to. the hypothesis of Laplace, onr system mayhave originated, a very large amount of meteoric matterexisted in its midst, or in the regions through which it wastravelling, and that the aggregation of such matter had muchto do with the formation of the various planets. It is wellknown that a considerable quantity of meteoric matter is stillscattered throughout the Solar System ; hut iu ages long pastit was probably much more abundant.

In those times long ago, may it not he, that comparativelylittle of such matter as lay within the orbit of Mars escapedthe powerful attraction of the Sun, and that what did so escaperemained in an especially fine state of division ? If so, wecan understand why it is that such meteorites as are con-stantly passing through the Earth ’s atmosphere, and fallingupon its surface in the form of shooting stars, are exceed-ingly minute in size.

But to proceed with our explanation of this hypothesis. Itmay also be supposed, that the neighbourhood of the largerplanets, and especially that of Jupiter and Saturn , at a distancewhere the attraction of the central mass of the Sun wouldhave a greatly diminished effect, has supplied a great quantityof such matter towards the formation of their globes. At thesame time we may conceive, that, at a distance from the Sunlying between about 150,000,000 and 400,000,000 miles,meteoric masses, somewhat larger in size than those whichexist nearer to it, might still remain in their pristine orbits,the inclinations of which orbits might in some cases be veryconsiderable. These may be really the bodies to which wegive the name of Minor Planets. The Minor Planets, uponthis supposition, may perhaps be considered the best examplesextant of the original condition of some of the primeval matterof the Solar System .

This same hypothesis, which, however, we must confess isdevoid of any certain evidence, also suggests that, in the vastspaces between the orbits of Jupiter and Saturn, of Saturn and Uranus, of Uranus and Neptune, —spaces so vast that theattractions of their great globes would, owing to the effect of