
Two 4000 ft plumb bobs hung down a mine shaft, with baffling results (1901) - andrewljohnson
http://www.lhup.edu/~dsimanek/hollow/tamarack.htm
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Groxx
Skimmed, but what I gathered is:

The plumb lines diverged a bit. According to Palmer this means the earth is
hollow, and everyone except him is chocking it up to air currents. Clearly,
they can be pretty significant at that sort of distance. Few have been able to
replicate the results all, and most get the expected results (parallel, with
room for jostling / air currents randomizing).

Feel free to correct me if I'm wrong. It's too much to absorb right now.

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jcdreads
That, and he completely ignored coriolis forces, which apparently explain the
divergence nicely.

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snowbird122
This is long, but interesting so let me try to summarize.

In early 1900s, two lines measuring 4250 feet each were hung down a mine shaft
on several occasions in order to calculate the radius of the earth. Scientists
expected the bottom of the lines to be closer together than the top, but the
opposite was found to be true. The bottom of the lines was 8.2 inches further
apart than the top. Several theories were put forth to explain the reasoning
behind this, but all failed to account for the large discrepancy from the
expected results.

This was my favorite theory: _One central tenet of Teed's philosophy held that
the earth is a hollow rock shell, and we live and walk on the inside surface
of this shell. The entire universe, which is mostly an illusion caused by
gravic and levic rays and light, lies within this shell. This complicated view
was called the cellular cosmogony, the earth-cell theory or the Koreshan
cosmogony._

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teilo
Hmmm. I wonder want's on the outside then... Seems to cause more problems than
it solves, even for the simple-minded folk who believe this (and I have met at
least one guy who believed this).

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plaes
Don't forget, that first space flight came 50 years later...

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nazgulnarsil
this sort of story illustrates what a wikipedia type repository of knowledge
misses. wikipedia will typically have the most up to date explanation of an
event or phenomena, but it can be very illuminating to see past wrong
explanations and the people and situations which gave rise to those incorrect
explanations. this is even more valuable on topics where heavy revisionism has
made it difficult to discern why the current explanation is accepted.

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derefr
Eventually, Wikipedia will also be a source of past-wrong explanations, in the
form of years-old page revisions.

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nazgulnarsil
i have a feeling that old page revisions aren't considered that valuable and
significantly old ones may be dropped.

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bdonlan
No, they're not dropped, as that would violate attribution requirements. They
are, however, compacted and compressed to take less space (at the expense of
more CPU to access, but the typical user won't notice this)

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tlb
Divergences are given in so many units it's really hard to compare anything.
Examples: 0.018 foot, 0.04 inch, 0.045 cm.

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JabavuAdams
There are 12 inches in a foot, and 2.54 cm in an inch. What's the problem?

