Archimedes Texts

342
gresse I make is not in plano, but about the circumference of the
Terrestrial Globe, which at every step changeth inclination in
respect to Heaven, and consequently maketh the same change
in the Instrument which is erected upon the same.

SAGR. You say very well: And you know withal, that by
how much the bigger that circle shall be upon which you move,
so many more miles you are to walk, to make the said star to
rise that same degree higher; and that sinally if the motion to
wards the star should be in a right line, you ought to move yet
farther, than if it were about the circumference of never so
great a circle?

SALV. True: For in short the circumference of an infinite
circle, and a right line are the same thing.

SAGR. But this I do not understand, nor as I believe, doth
Simplicius apprehend the same; and it must needs be concealed
from us under some mistery, for we know that Salviatus never
speaks at random, nor proposeth any Paradox, which doth not
break forth into some conceit, not trivial in the least. Therefore
in due time and place I will put you in mind to demonstrate this,
that the right line is the same with the circumference of an infi
nite circle, but at present I am unwilling that we should inter
rupt the discourse in hand. Returning then to the case, I pro
pose to the consideration of Simplicius, how the accession and
recession that the Earth makes from the said fixed star which is
neer the Pole can be made as it were by a right line, for such is
the Diameter of the Grand Orb, so that the attempting to re
gulate the elevation and depression of the Polar star by the mo
tion along the said Diameter, as if it were by the motion about
the little circle of the Earth, is a great argument of but little
judgment.

SIMP. But we continue still unsatisfied, in regard that the
said small mutation that should be therein, would not be discer
ned; and if this be null, then must the annual motion about
the Grand Orb ascribed to the Earth, be null also.

SAGR. Here now I give Salviatus leave to go on, who as I
believe will not overpasse the elevation and depression of the
Polar star or any other of those that are fixed as null, although
not discovered by any one, and affirmed by Copernicus himself
to be, I will not say null, but unobservable by reason of its
minuity.

SALV. I have already said above, that I do not think that

any one did ever set himself to observe, whether in different times
of the year there is any mutation to be seen in the fixed stars, that
may have a dependance on the annual motion of the Earth, and
added withal, that I doubted least haply some might never have