in fact, its whole light is composed of
nothing but stars of every magnitude from such as are visible to the
naked eye down to the smallest points of light perceptible with the best
telescopes.

These phenomena agree with the supposition that the stars of our
firmament, instead of being scattered indifferently in all directions
through space, form a stratum of which the thickness is small in
comparison with its length and breadth; and in which the earth occupies
a place somewhere about the middle of its thickness and near the point
where it subdivides into two principal laminae inclined at a small angle
to each other. For it is certain that to an eye so situated the apparent
density of the stars, supposing them pretty equally scattered through
the space they occupy, would be least in the direction of the visual ray
perpendicular to the lamina, and greatest in that of its breadth;
increasing rapidly in passing from one to the other direction, just as
we see a slight haze in the atmosphere thickening into a decided
fog-bank near the horizon by the rapid increase of the mere length of
the visual ray.

Such is the view of the construction of the starry firmament taken by
Sir William Herschel, whose powerful telescopes first effected a
complete analysis of this wonderful zone, and demonstrated the fact of
its entirely consisting of stars.

So crowded are they in some parts of it that by counting the stars in a
single field of his telescope he was led to conclude that 50,000 had
passed under his review in a zone two degrees in breadth during a single
hour's observation. The immense distances at which the remoter regions
must be situated will sufficiently account for the vast predominance of
small magnitudes which are observed in it.

The process of gauging the heavens was devised by Sir William Herschel
for this purpose. It consisted simply in counting the stars of all
magnitudes which occur in single fields of view, of fifteen minutes in
diameter, visible through a reflecting telescope of 18 inches aperture,
and 20 feet focal length, with a magnifying power of 180 degrees, the
points of observation being very numerous and taken indiscriminately in
every part of the surface of the sphere visible in our latitudes.

On a comparison of many hundred such "gauges," or local enumerations, it
appears that the density of starlight (or the number of stars existing
on an average of several such enumerations in any one immediate
n