_vision_. The time would be, as Dr. Nichol computes, about two
hundred and fifty millions of years, supposing that our rate of
travelling was about three times that of our earth in its orbit. Now,
as the velocity is assumed to be the same in both cases, the ratio
between the distance (already so tremendous) of Bessel's 61
_Cygni_, and that of Lord Rosse's farthest frontier, is as forty-
one thousand to two hundred and fifty millions. This is a simple rule-
of-three problem for a child. And the answer to it will, perhaps,
convey the simplest expression of the superhuman power lodged in the
new telescope:--as is the ratio of forty-one thousand to two hundred
and fifty million, so is the ratio of our own distance from the sun
multiplied by six hundred and seventy thousand, to the outermost limit
of Lord Rosse's sidereal vision.]

Another class, and a frequent one, of equivocal phenomena, phenomena
that are reconcilable indifferently with either of two assumptions,
though less plausibly reconciled with the one than with the other,
concerns the position of stars that seem connected with each other by
systematic relations, and which yet _may_ lie in very different
depths of space, being brought into seeming connection only by the
human eye. There have been, and there are, cases where two stars
dissemble an interconnection which they really _have_, and other
cases where they simulate an interconnection which they have not. All
these cases of simulation and dissimulation torment the astronomer by
multiplying his perplexities, and deepening the difficulty of escaping
them. He cannot get at the truth: in many cases, magnitude and distance
are in collusion with each other to deceive him: motion subjective is
in collusion with motion objective; duplex systems are in collusion
with fraudulent stars, having no real partnership whatever, but
mimicking such a partnership by means of the limitations or errors