TOTAL NUMBER DISCOVERED. 



the balcony of his apartment, No. 12, Rue de Seine, in the 

 Faubourg St. Germain. 



15. By inspecting the above table, it will be seen that these thirty- 

 three planets move within a region of the solar system comprised 

 between 2 '2 and 3-2 times the mean distance of the earth. Their 

 magnitudes are too minute to be ascertained with any degree of 

 precision and certainty by any means of measurement hitherto 

 discovered, and it may be inferred, with great probability, that 

 they do not in general exceed 100 miles, that is, the 80th 

 part of the diameter of the earth. Assuming, then, such to 

 be their mean dimensions, and considering that the bulk of globes 

 is in the proportion of the cubes of their diameters, it would 

 follow, that, to make a globe as large as the earth, it would be 

 necessary that 512000 such planets as these should be rolled 

 into one. 



16. It will not fail to be observed, what great probability this 

 extreme minuteness of bulk, combined with the circumstance of 

 their being all so nearly at the same distance from the sun, gives 

 to the hypothesis of Dr. Olbers. 



To show the relative position of this group of planets and those 

 of the larger members of the system, we have represented in fig. 1, 

 in their proper proportions, the successive distances of the planets 

 from the sun, the place of these new planets being indicated by 

 the band of parallel circles drawn in close proximity. 



Being distinguished from the other planets of the system by so 

 many singular circumstances, some astronomers denominated 

 these bodies Asteroids; we think, however, that, for reasons that 

 must be obvious, the name Planetoids would be preferable. 



17. From the minuteness of their masses, the force of gravity 

 on the surface of these bodies must be very inconsiderable ; and 

 this would account for a circumstance which has been observed 

 on some of them, namely, that their atmospheres are relatively 

 much more extensive than those of the larger planets, since the 

 same mass of air, feebly attracted, would dilate into a volume 

 comparatively enormous. Muscular power would be more effica- 

 cious on them in the same proportion ; thus, a man might spring 

 upwards through sixty or eighty perpendicular feet, and return 

 to the ground, sustaining no greater shock than would be felt 

 upon the earth in descending from the height of two or three 

 feet. " On such planets," observes Herschel, "giants might 

 exist, and those enormous animals which on earth require the 

 buoyant power of water to counteract their weight." 



169 



