Date: 12-23-96 (23:23)              Number: 84 of 95 (Refer# NONE)
  To: ALL
From: pedrotti@slip.net, PETER PEDROTTI
Subj: Re: Greeks knew world is round --- and measured it! Was: Re:
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Conf: alt.freemasonry (12)       Read Type: GENERAL (A) (+)

Newsgroups: alt.freemasonry
Organization: Slip.Net
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On Sun, 22 Dec 1996 02:58:16 UNDEFINED, af@atl-intl.com wrote:

>For whatever it is worth, the Greeks not only knew the world to be round,
>a pretty good estimate of its size was made by geometry; the method was
>to use the different angles of noon shadows measured in two latitudes and
>to calculate from that.
>
>A great deal of knowledge was lost with the burning of the library of
>Alexandria; in fact, the European Dark Ages had more primitive technology
>than had been possessed by the pre-Christian Romans and Greeks.
>
>    Regards and well wishes,
>    David
>
>>Weren't the globes originally bowls of some kind, used to hold oil? I
>>don't recall where I read that but it stuck in my mind when considering
>>just the point raised in this thread, i.e. globes during a period when
>>the world was considered flat.
>
>>: > building of King Soloman's Temple, if it was widely beleived and
>>: > accepted as fact that the world was round?
>
>>: Do you mean that the world was flat?  If so, it's a very good question.
>>: I will also be interested in the answers.
>
On Sun, 22 Dec 1996 02:58:16 UNDEFINED, af@atl-intl.com wrote:

>For whatever it is worth, the Greeks not only knew the world to be round,
>a pretty good estimate of its size was made by geometry; the method was
>to use the different angles of noon shadows measured in two latitudes and
>to calculate from that.
>
>A great deal of knowledge was lost with the burning of the library of
>Alexandria; in fact, the European Dark Ages had more primitive technology
>than had been possessed by the pre-Christian Romans and Greeks.
>
>    Regards and well wishes,
>    David

David,

There were, as I understand it (from Astronomy 1 at UC Berkeley once
upon a time), two separate lines of thought in ancient Greece on this
subject. They, like everyone else in the ancient world, thought Earth
to be flat and that the Sun and Moon revolved around the Earth. Even
so, being consummate geometers and observational astronomers, they did
correctly figure that the Sun, Earth and Moon were lined up during
lunar eclipses.  It was speculated that the earth is a round flat disc
based on the (correct) guess that the darkening of the moon during a
eclipse, which has a circular edge, was the Earth's shadow.  Nobody
seems to have guessed, however, that the Earth is a sphere, just that
the perimeter of the flat Earth is circular.

The second, and remarkable piece of astronomy was the simultaneous
observation of the elevation of the moon from different latitudes, as
you describe. Assuming a flat Earth, the experiment was thought to
give the distance to the Moon by "triangulation". Since the Greeks
assumed the Moon is fairly close, they didn't realize that within
their experimental error, the distance should have been treated as
effectively infinite and that the two lines of sight should thus have
been considered parallel. There is enough of the Earth's curvature
between Greece and Egypt that the elevation difference gave them an
excellent estimate of the radius of the Earth, but they did not
recognize their result for what it was at the time. If the idea that
the Earth is a sphere ever occured to them, they probably discounted
it because foreigners would have fallen off.

It is more probable that the "pommel, or ball representing a globe"
atop the Masonic Boaz is simply a modern anachronism like the clocks
that chime in several of Shakespeare's plays (hmm... more evidence
that he wrote the ritual?). The pommel on Jachin, however, is the
Celestial Sphere or "situation of the fixed stars", which did figure
in several ancient astronomical theories and is a useful approximation
today. Neither is mentioned in the biblical accounts of Hiram's
(Hurums's) pillars (Kings I, 7:13-22, Chronicles II, 2:13-14,
Chronicles II, 3:15-17).

F&S,

Peter Pedrotti, PM
Oakland, CA  USA



P.S.,

More of the story gradually comes back to me.  The Greeks measured the
distance to the Sun using the shadows of vertical rods and the
elevation of the Moon using a sort of inverted sextant that measured
the angle away from a vertical plumbline, the complement of the
elevation above the horizon.  To their surprise, the two measurements
agreed fairly well and they concluded that the Sun and Moon were the
same distance from the Earth, that distance being fairly close to the
actual radius of the Earth, and for the same reason.  This result made
emminent sense to them, because the Sun and Moon happen to both be
about 109 times as distant as their own diameters, causing them to
appear the same size ("subtend the same angles").  They fit almost
exactly during solar eclipses, sometimes the Moon appears slightly
larger, sometimes slightly smaller than the apparent Sun, depending on
where in Earth's orbit the eclipse occurs.

Peter


