86 KANT'S UNIVERSAL NATURAL HISTORY 



near it as Mercury, it would burn like a comet, and that 

 its matter would not have sufficient fire-resisting power 

 not to be dissipated by such heat. But how much more 

 would not the proper matter of the sun itself, which is at 

 least four times lighter than that of the earth, be destroyed 

 by this glowing heat? And why is the moon twice denser 

 than the earth, seeing that it revolves with it at the same 

 distance from the sun? We cannot therefore attribute the 

 proportioned densities of the planets to their relation to 

 the heat of the sun without being involved in the 

 greatest contradictions. We rather see that a cause which 

 distributes the planets in their places according to 

 the density of their mass, must have had a relation to 

 their internal matter and not to their surface. It must, 

 notwithstanding this result which it determined, still allow 

 a diversity of material in the same heavenly body, and 

 establish this relation of density only in the sum total of 

 its composition. I leave it to the perspicuity of the reader 

 to judge whether any other statical law than that which 

 is presented in our theory, can satisfy all these conditions. 

 The relation between the densities of the planets in- 

 volves another circumstance which, by its complete 

 harmony with the explanation already indicated, corrobo- 

 rates the correctness of our theory. The heavenly body 

 which stands in the centre of other orbs revolving round 

 it, is usually lighter than the body which revolves nearest 

 it. The earth compared with the moon, and the sun 

 compared with the earth, show such a relation between 

 their densities. According to the scheme which we have 

 presented such a constitution is necessary. For as the 

 inferior planets have been formed mainly from the out- 

 shot of the elementary matter which by the superiority 



