f this was another layer of
rose-colored clouds. To this theory Arago, Sir John Herschel and
Humboldt assented. But Le Verrier declares that the facts observed
during late eclipses are contrary to this theory, and a new theory is
slow in process of construction, to be demolished in its turn by later
observations.[344]

One of the most recent theories is that the fuel is furnished by a
stream of meteorites, planetoids, and comets, falling in by the power of
attraction, and being speedily converted into gas flames; a process the
very reverse of the theory of the evolution of the solid celestial
bodies from gas. But it is pretty evident from these conflicting
theories that nobody knows anything certainly as to the materials of the
sun, or the fuel which feeds his flames. But if the very best
astronomers do not know of what he is made, is it not too great a demand
upon our credulity to ask us to believe that they can tell how he was
made?

The size, density, and distances of the planets, which form such
essential elements in the calculations of the nebular theory of
evolution, are equally uncertain. Ten or twelve years ago Mercury was
believed to be nearly three times as dense as the earth (2.94); and the
theory of evolution was partly based upon this assumed fact. But Hausen
now finds that it is not half so dense; that, as compared with the
earth, it is only 1.22; and that its mass is less than half (5/12) of
what had been confidently calculated.[345] Corrections of the masses and
densities of other planets are also offered.

Still wider differences prevail in calculating the velocities of these
bodies; velocities _calculated_ and found to correspond with the theory
of evolution. Bianchini gives the period of the rotation of Venus at
twenty-four days, eight hours; but Schroeter says it is not as many
hours as Bianchini gives days; that it is only twenty-three hours and
twenty minutes. Sir Wm. Herschel can not tell which is right, or whether
both are wrong.[346]

From such imperfect and erroneous calculations astronomers have deduced
what they called a _law_, which holds the same place in nature that the
Blue Laws of Connecticut maintain in history; and which like them have
imposed upon the credulous. Titius and Bode imagined that they had
discovered that, "When the distances of the planets are examined, it is
found that they are almost all removed from each other by distances
which are in the same proportion as their