A second large order of equivocating appearances will arise,--not as to magnitude, but as to motion. If it could be a safe assumption, that the system to which our planet is attached were absolutely fixed and motionless, except as regards its own _internal_ relations of movement, then every change outside of us, every motion that the registers of astronomy had established, would be objective and not subjective. It would be safe to pronounce at once that it was a motion in the object contemplated, _not_ in the subject contemplating. Or, reversely, if it were safe to assume as a universal law, that no motion was possible in the starry heavens, then every change of relations in space, between ourselves and them, would indicate and would measure a progress, or regress, on the part of our solar system, in certain known directions. But now, because it is not safe to rest in 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 _vision_. The time would be, as Dr. Nichol computes, about two