i88 3 .] 
of the Solar System, 
197 
proportion to the system — our Moon; planet A may show 
something similar. The Moon as mass does not belong to 
the Earth : the quantity of the latter was too great ; it 
threw off the surplus which did not reach its aim — Mars. 
Mercury, the co-planet of the Earth, thus probably also 
obtained more mass ; i-i/j-th of the mass of our moon it 
ought to be. 
This disturbance, perceptible with Saturn, is probably 
connected with the asteroids. The mass of them has thus 
to be equal to — 
8*8 x I*22 „ 1 
680 3 29,500,000 
of that of the Sun. 
The mean distance of Flora is 471^; of Hygiea, 671 r. 
680 (77*3 r x 2*96) = 456 ^ = 397 r x 
1*22 
1-05* 
The former is in the mean little beyond that region, in which 
the inner projection might have seized it ; the latter still 
inside 680 r, not far from the original central planetary mass. 
Both are in that region which appears like empty at the head 
of the comet between nucleus and envelope. Should not a 
number of such asteroids, 276 times less in mass, exist be- 
tween 3676 r and 3820 r distance ? 
The mass of the Moon is 1-87 of that of the Earth ; it is 
1-31,282,500 of the Sun, if we add the 1-14*87 which the 
mass of Mercury appeared larger than Enke’s calculation 
made it out ; the quantity becomes 1-29,500,000 of the solar 
mass : others give the mass of the Moon 1-81 of that of the 
Earth, which at once gives 1-29,500,000 of that of the Sun. 
The diameter of our Moon is 454 geographical miles ; that 
of the largest of the planetoids is believed not to exceed 
145 miles : it would require twenty-eight such bodies, of 
equal density with our Moon, to make up the latter. 
I made the mass of Mars 1- 2,345,112 of the Sun. Astro- 
nomy gives it 1-2,680,337 : if we deduct from the former 
figure the mass of our Moon, 1-29,500,000, and the plus of 
Mercury (or possibly of a lunar system), we get about the 
second figure (but even the mass of the planetoids may be 
considered a reduction of the mass of Mars). 
I return from these problematic tertiary relations to the 
secondary. We found the density of the central parts to 
agree with observation ; the latter gives the densities 
that of the earth, rooo; the Sun, 0*252; Mercury, 1*234; 
