eceived in the beginning may prevent them from all coming together, at
least for millions of ages. Some of these nebulae, he adds, cannot well
be supposed to be at a less distance from us than six or eight thousand
times the distance of Sirius(63). Kepler however denies that each star,
of those which distinctly present themselves to our sight, can have its
system of planets as our sun has, and considers them as all fixed in the
same surface or sphere; since, if one of them were twice or thrice
as remote as another, it would, supposing their real magnitudes to be
equal, appear to be twice or thrice as small, whereas there is not in
their apparent magnitudes the slightest difference(64).

(62) Encycl. Lond. Vol. II, p. 411.

(63) Ibid, p. 348.

(64) Ibid, p. 411.

Certainly the astronomers are a very fortunate and privileged race of
men, who talk to us in this oracular way of "the unseen things of God
from the creation of the world," hanging up their conclusions upon
invisible hooks, while the rest of mankind sit listening gravely to
their responses, and unreservedly "acknowledging that their science is
the most sublime, the most interesting, and the most useful of all the
sciences cultivated by man(65)."

(65) Ferguson, Astronomy, Section 1.

We have a sensation, which we call the sensation of distance. It comes
to us from our sight and our other senses. It does not come immediately
by the organ of sight. It has been proved, that the objects we see,
previously to the comparison and correction of the reports of the organ
of sight with those of the other senses, do not suggest to us the idea
of distance, but that on the contrary whatever we see seems to touch the
eye, even as the objects of the sense of feeling touch the skin.

But, in proportion as we compare the impressions made upon our organs of
sight with the impressions made on the other senses, we come gradually
to connect with the objects we see the idea of distance. I put out
my hand, and find at first that an object of my sense of sight is not
within the reach of my hand. I put out my hand farther, or by walking
advance my body in the direction of the object, and I am enabled to
reach it. From smaller experiments I proceed to greater. I walk towards
a tree or a building, the figure of which presents itself to my eye,
but which I find upon trial to have been far from me. I travel towards
a place that I cannot see, but which I am told