PORTION OF THE COSMOS. THE PLANETS. 



323 



Still larger, although remarkably near to the truth, was 

 the mass ( 93 - 22 ) deduced for Neptune by Le Verrier from 

 his ingenious calculations previous to the actual discovery 

 of the planet by Galle. The following is the arrangement 

 of the planets according to their masses, beginning with the 

 least (omitting the smaller planets, Ceres, Pallas, Juno, &c.), 

 and proceeding in increasing order : Mercury, Mars, Yenus, 

 Earth, Uranus, Neptune, Saturn, and Jupiter. 



It will be seen that this order of succession (as in the 

 case of the volumes and densities) is by no means identical 

 with that of the distances from the central body. 



6. Density of the Planets. Employing the previously 

 given volumes and masses, we obtain for the densities of the 

 planets (taking respectively the densities of the Earth and 

 that of "Water as unity) the following numerical ratios : 



In the above table the comparison of the densities of the 

 different planets with that of water is based on the density 

 of our own globe. This was given by Beich's experiments 

 with the torsion-balance made at Ereiberg, 5 '4383 ; the 

 analogous earlier experiments of Cavendish give, according 



