THE PLANETOIDS. 23 



It will be seen, however, that in this table of distances 

 there is one great exception to the rule, namely the distance 

 between Mars and Jupiter, which is nearly double what it 

 should be according to this rule, giving rise to the idea 

 that a planet ought to be placed between them. Professor 

 Bode was so convinced that something of the kind was 

 necessary to complete the harmony of the series, that he 

 caused to be instituted a search for the supposed planet, 

 and according to his conjecture one was discovered as nearly 

 as possible in the situation indicated, but upon more accurate 

 information being obtained, this planet was found to be so 

 small (scarcely 150 miles diameter) that it could hardly be 

 considered as a planet ranging with the others, and having 

 so large a space of the heavens to itself; shortly afterwards 

 another small planet was discovered, having nearly the same 

 orbit. From time to time others have been discovered, to the 

 number of forty-two, up to the present date. Dr. Olbers 

 upon discovering the second of these small bodies, where 

 one great one was anticipated, put forth the curious 

 hypothesis, that one large planet had really existed there 

 at some former time, that it had been shattered into pieces 

 by some accident, such as an internal explosion, and that 

 more of these pieces would be found; it is curious how 

 accurately this prediction has been verified. 



If we suppose the original planet to have been liquid when 

 shattered to pieces, it would fully account for the fragments 

 being spherical, just as globules of mercury assume this 

 form from their own attraction of gravitation, and that the 

 planets, our own earth amongst them, are liquid, is very 

 nearly proved by their forms, which are exactly such as fluid 

 masses rotating on an axis would assume, moreover the 

 specific gravity of some of the planets is but little more 

 than that of water, and with respect to our earth, the 

 evidence of internal heat, increasing as we descend below 

 the surface, &c., show almost beyond doubt that at the 

 present time it is in a liquid state (molten) covered over 

 by a few miles' thickness of hardened crust, which bears 

 such a small proportion to the bulk of the globe, that the 

 whole may be considered as liquid. 



