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The ancient philosophers took the earth as a common measure and
then measured the stars, the planets,
and the firmament. After this
they wanted to measure the moon and prove its size.
They found that the body of the whole earth, externally
and internally, which was their common measure, was
thirty-nine times (and a bit more) greater than the body
of the moon; it was twenty-three times, plus one half and five-twelfths,
as high above the earth as the earth's thickness in its central part.
Similarly, with regard to the sun, they proved by true
demonstration and reason that it is 166 times larger
than the whole earth. Those who know nothing of this
will have great trouble believing it, but it is sufficiently
proven as much by the mastery as by the true sense of geometry,
in which subject many people
have been toiling and working from the time of the philosophers onward,
in order to know the truth of this, whether it was indeed
as said or not, so much so that by lively (see note) reason
they proved that the ancients had said the truth
both about the quantity and the height. And with regard to