DOI Page / Citation link:
https://doi.org/10.11588/diglit.15#0095
THE PROBLEM OF THE PYRAMIDS. 85
way that it affects the sun, and the nearer a star is
to the horizon, the more it is raised by atmospheric
refraction. The pole-star in both its positions—•
that is, when passing below the pole, and when
passing above that point—is raised by refraction,
rather more when below than when above ; but
the estimated position of the pole itself, raised by
about the mean of these two effects, is in fact
raised almost exactly as much as it would be if it
were itself directly observed (that is, if a star occu-
pied the pole itself, instead of merely circling close
round the pole). We may then simplify matters
by leaving out of consideration at present all
questions of the actual pole-star in the time of
the pyramid builders, and simply considering how
far they would have set the pyramid's base in
error, if they had determined their latitude by
observing a star occupying the position of the true
pole of the heavens.
They would have endeavoured to determine
where the pole appears to be raised exactly thirty
degrees above the horizon. But the effect of re-
fraction being to raise every celestial object above
its true position, they would have supposed the
pole to be raised thirty degrees, when in reality it
was less raised than this. In other words, they
would have supposed they were in latitude 30o,
way that it affects the sun, and the nearer a star is
to the horizon, the more it is raised by atmospheric
refraction. The pole-star in both its positions—•
that is, when passing below the pole, and when
passing above that point—is raised by refraction,
rather more when below than when above ; but
the estimated position of the pole itself, raised by
about the mean of these two effects, is in fact
raised almost exactly as much as it would be if it
were itself directly observed (that is, if a star occu-
pied the pole itself, instead of merely circling close
round the pole). We may then simplify matters
by leaving out of consideration at present all
questions of the actual pole-star in the time of
the pyramid builders, and simply considering how
far they would have set the pyramid's base in
error, if they had determined their latitude by
observing a star occupying the position of the true
pole of the heavens.
They would have endeavoured to determine
where the pole appears to be raised exactly thirty
degrees above the horizon. But the effect of re-
fraction being to raise every celestial object above
its true position, they would have supposed the
pole to be raised thirty degrees, when in reality it
was less raised than this. In other words, they
would have supposed they were in latitude 30o,