Read. (Measurement of Earth's Circumference)
That experiment is actually measuring the diameter of the Flat Earth, not the circumference of the Round Earth. This is why the diameter listed in the FAQ is identical to the circumference listed for the Round Earth. The earth is merely
assumed to be round in the experiment you've posted.
Scroll to the bottom of that link:
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An Alternative ModelEratosthenes' model depends on the assumption that the earth is round and that the sun is far away, therefore produces parallel rays of light all over the earth. If the sun is nearby, then shadows will change length even for a flat earth. A flat earth model is sketched at the right. The vertical stick casts shadows that grow longer as the stick moves to the left, away from the closest point to the sun. (The sun is at height h above the earth.)
A little trigonometry shows that

Using the values 50 degrees and 60 degrees as measured on the trip, with b=1000 miles, we find that h is approximately 2000 miles. This relatively close sun would have been quite plausible to the ancients.
Continuing the calculation, we find that a is approximately 2400 miles and the two distances R1 and R2 are approximately 3000 and 3900 miles, respectively.
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Therefore your own source proves you to be wrong. Your source even shows that Eratosthenes' experiment actually proves the sun to be around 3,000 miles above the surface of the earth under FE.
Read (download the pdf - spherical Earth on a simple pendulum).
The earth does not rotate. The stars do. The pendulum rotates due to the stars capturing the weight of the pendulum geometrically as they spin above the hub of the earth.
While he excelled in many areas, Eratosthenes became one of the greatest geographers of all ages by establishing the mathematical geography of the spherical earth.
Erathostenes' experiment with shadows was actually measuring the diameter of the Flat Earth, not the circumference of the Round Earth. Erathostenes just assumed that the earth was round in his experiment. His experiment is the same as the one in your first link.
Read. (Flying clocks)
Albert Einstein has shown in his Principle of Equivalence that Acceleration bends space time in the same fashion as "gravity" would. Therefore the results of the flying clocks experiment would be identical in both models.
Read. (Gravitation field)
Albert Einstein has shown that an accelerating body creates the same effect of gravitation. See his Equivalence Principle.
For more information see
http://xxx.lanl.gov/ftp/physics/papers/0204/0204044.pdf"However one of the main tenants of general relativity is the Principle of Equivalence: A uniform gravitational field is equivalent to a uniformly accelerating frame of reference. This implies that one can create a uniform gravitational field simply by changing one’s frame of reference from an inertial frame of reference to an accelerating frame, which is a rather difficult idea to accept."
Read. (Earth’s core tangent cylinder)
This is not an experiment pertaining to the shape of the earth.
Read. (History of Spherical Earth)
There are no experiments in this link pertaining to the shape of the earth.
Read. (The Christopher Colubmus voyage)
Columbus' voyage is possible on a Flat Earth. Circumnavigation is possible on a Flat Earth.
Read. (Wiki)
There are no experiments in this link pertaining to the shape of the earth.
To save your time, just accept reality and don't read these.
Apparently you didn't even read your sources and just posted random stuff from Google, because your sources do not show that the earth is spherical at all. Not a single one was studying the shape of the earth. In fact, your first post proves the sun to be around 3,000 miles above the sea level of the earth.