either assumption, the range of possibilities for which science has to
provide, is enlarged; the immediate difficulties are multiplied; but
with the result (as in the former case) of reversionally expanding the
powers, and consequently the facilities, lodged both in the science and
in the arts ministerial to the science. Thus, in the constellation
_Cygnus_, there is a star gradually changing its relation to our
system, whose distance from ourselves (as Dr. Nichol tells us) is
ascertained to be about six hundred and seventy thousand times our own
distance from the sun: that is, neglecting minute accuracy, about six
hundred and seventy thousand stages of one hundred million miles each.
This point being known, it falls within the _arts_ of astronomy to
translate this apparent angular motion into miles; and presuming this
change of relation to be not in the star, but really in ourselves, we
may deduce the velocity of our course, we may enter into our _log_
daily the rate at which our whole solar system is running. Bessel, it
seems, the eminent astronomer who died lately, computed this velocity
to be such (viz., three times that of our own earth in its proper
orbit) as would carry us to the star in forty-one thousand years. But,
in the mean time, the astronomer is to hold in reserve some small share
of his attention, some trifle of a side-glance, now and then, to the
possibility of an error, after all, in the main assumption: he must
watch the indications, if any such should arise, that not ourselves,
but the star in _Cygnus_, is the real party concerned, in drifting
at this shocking rate, with no prospect of coming to an anchorage.
[Footnote: It is worth adding at this point, whilst the reader
remembers without effort the numbers, viz., forty-one thousand
years, for the time, (the space being our own distance from the sun
repeated six hundred and seventy thousand times,) what would be the
time required for reaching, in the _body_, that distance to which
Lord Rosse's six feet mirror has so recently extended our