. I cannot
conceive of a wider area than that which the sight commands from
the summit of a lofty eminence. I can pass in imagination through
many such areas. I can add field to field _ad infinitum_; and thus
conceive of infinite space, by conceiving of a space which can be
infinitely added to; but all of space that I can take in at one
process, is an area commensurate with that embraced at a glance by
the eye. How, then, have I my conception of the earth as a
whole--of the solar system as a whole--nay, of many systems as a
whole? Just as I have my conceptions of a school-globe or of an
Orrery--by diminution. It is through the diminution induced by
distance that the sidereal heavens only co-extend, as seen from the
top of Tor-Achilty, with a portion of the counties of Ross and
Inverness. The apparent area is the same, but the colouring is
different. Our ideas of greatness, then, are much less dependent on
actual area than on what painters term aerial perspective. The
dimness of distance, and the diminution of parts, are essential to
right conceptions of great magnitude.

"Of the various figures presented to me here, I seize strong hold
of but one. I brood over the picture of the solar system conjured
up. I conceive of the satellites as light shallops that continually
sail round heavier vessels, and consider how much more of space
they must traverse than the orbs to which they are attached. The
entire system is presented to me as an Orrery of the apparent size
of the area of landscape seen from the hill-top; but dimness and
darkness prevent the diminution from communicating that appearance
of littleness to the whole which would attach to it, were it, like
an actual Orrery, sharply defined and clear. As the picture rises
before me, the entire system seems to possess, what I suspect it
wants, its atmosphere like that of the earth, which reflects the
light of the sun in the different degrees of excessive
brightness--noon-tide splendour, the fainter shades of evening, and
grey twilight obscurity. This veil of light is thickest towards the
centre of the system; for when the glance rests on its edges, the
suns of other systems may be seen peeping through. I see Mercury
sparkling to the sun, with its oceans of molten glass, and its
fountains of liquid