happen to be in conjunction with the nebula, and thus
appear for a short time to be projected upon its disc.

There is one consideration of some weight, though we have never seen it
adverted to, which tends directly to confute the nebular hypothesis.
That faint radiance called the zodiacal light, which is seen to stream
up in the form of a cone from our sun, is assumed by our author to be a
residuum of the nebulous matter belonging to our system, which has not
yet been drawn into the sun, though it is on its way thither. Others
have supposed, with far more probability, that it is the sun's
atmosphere, and therefore its present shape and size will never
change,--as they never have changed, during the period in which they
have been observed by man. But no matter; we are now reasoning upon our
author's hypothesis. If the zodiacal light be composed of primitive
nebulous matter, it must now be comparatively thick and dense, since the
process of aggregation has been going on for countless ages, and, in our
system, is considered as nearly completed; just as when a sediment is
forming in a tumbler full of turbid water, after the upper portion of
the fluid has become entirely clear, there will be a stratum of water
next to the sediment more turbid than the whole was before the
deposition began. Yet this light is very faint, when seen only from the
distance of our earth; and at the boundaries of our system, from the
orbit of Uranus, for instance, we cannot believe that it is visible at
all. Is it likely, then, that a portion of this nebulous matter, in
which the process of deposition has hardly begun, and which is seen from
a distance so vast, that in comparison with it the whole diameter of our
solar system is but a point, would be visible from this earth? In the
case of the other nebulae, a multitude of perfectly formed suns, uniting
their respective beams, are seen only as a faint, whitish speck on the
blue arch. And yet we are required to believe, that the luminous matter
which will ultimately form but one sun, or perhaps two, while still
thinly diffused over an immense tract of space, the process of
aggregation having hardly commenced, is yet visible to our eyes at this
vast distance.

"Credat Judaeus Apella;
Non ego."

We pass to the next chapter in the history, which professes to explain
the gradual formation of a solar system by a process of cooling and
shrinking, to which the central orb is exposed. A