So stood the case for a long time; it was settled to the
satisfaction of Europe that there were two classes of _nebulae_,
one that _were_ worlds, one that were _not_, but only the pabulum
of future worlds. Silence arose. A voice was heard, 'Let there
be Lord Rosse!' and immediately his telescope walked into Orion;
destroyed the supposed matter of stars; but, in return, created
immeasurable worlds.
As a hint for apprehending the delicacy and difficulty of the process
in sidereal astronomy, let the inexperienced reader figure to himself
these separate cases of perplexity: 1st, A perplexity where the dilemma
arises from the collision between magnitude and distance:--is the size
less, or the distance greater? 2dly, Where the dilemma arises between
motions, a motion in ourselves doubtfully confounded with a motion in
some external body; or, 3dly, Where it arises between possible
positions of an object: is it a real proximity that we see between two
stars, or simply an apparent proximity from lying in the same visual
line, though in far other depths of space? As regards the first
dilemma, we may suppose two laws, A and B, absolutely in contradiction,
laid down at starting: A, that all fixed stars are precisely at the
same _distance_; in this case every difference in the apparent
magnitude will indicate a corresponding difference in the real
magnitude, and will measure that difference.
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