Salusbury, Thomas, Mathematical collections and translations (Tome I), 1667

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1gr.m.gr.m.LandgravePolar altit.5118Altit. of the Star7930Gemma50507945
The other two are theſe
gr.m.gr.m.Buſchius.Polar Altitude5110Altit. of the Star7920Gemma.50507945Reinholdus.Polar Altitude5118Altit. of the Star7930Gemma.50507945
From what I have hitherto demonſtrated, you may gueſſe how
much this firſt way of finding out the diſtance of the Star, and
proving it ſublunary introduced by the Authour, maketh againſt
himſelf, and how much more probably and clearly the diſtance
thereof is collected to have been amongſt the more remote fixed
Stars.
SIMP. As to this particular, I think that the inefficacy of the
Authors demonftrations is very plainly diſcovered; But I ſee that all
this was compriſed in but a few leaves of his Book, and it may be,
that ſome other of his Arguments are more concluſive then theſe
firſt.
SALV. Rather they muſt needs be leſſe valid, if we will take
thoſe that lead the way for a proof of the reſt: For (as it is clear)
the uncertainty and inconcluſiveneſſe of thoſe, is manifeſtly
ſerved to derive it ſelf from the errours committed in the
mental obſervations, upon which the Polar Altitude, and height
of the Star was thought to have been juſtly taken, all in effect
having eaſily erred; And yet to find the Altitude of the Pole,
ſtronomers have had Ages of time to apply themſelves to it, at their
leaſure: and the Meridian Altitudes of the Star are eaſier to be
obſerved, as being moſt terminate, and yielding the Obſervator
ſome time to continue the ſame, in regard they change not ſenſibly,
in a ſhort time, as thoſe do that are remote from the Meridian.
And
if this be ſo, as it is moſt certain, what credit ſhall we give to
lations founded upon Obſervations more numerous, more difficult
to be wrought, more momentary in variation, and we may add,
with Inſtruments more incommodious and erroneous?
Upon a
ſlight peruſal of the enſuing demonſtrations, I ſee that the
putations are made upon Altitudes of the Star taken in different
Vertical Circles, which are called by the Arabick name, Azimuths; in
which obſervations moveable inſtruments are made uſe of, not
ly in the Vertical Circles, but in the Horizon alſo, at the ſame time;
inſomuch that it is requiſite in the ſame moment that the altitude
is taken, to have obſerved, in the Horizon, the diſtance of the

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