It is an acknowledged fact that ships at sea appear to sink below the horizon. However, this is inconsistent with Rowbotham's Bedford Level Experiment.
Rowbotham's Bedford Level experiment is easy to explain. Since it was a calm, sunny day and Rowbotham's telescope was 18 inches above the waterline, it's very likely that the temperature gradient of the air near the water was enough to induce a refractive phenomenon known as ducting. This would cause light rays from distant objects to follow the curvature of the earth and be visible even when the object is "over the horizon".
Oh, so the light was bendy. I'm sorry, but that's absolute nonsense as it is well-known that light doesn't bend. I mean, just think about all these times RE'ers said so. It must be true.
Dear PizzaPlanet,
Please stop misrepresenting the beliefs of those who you are debating, and please try to make an effort to actually understand where we are coming from. I have consistently put forth the effort to try to understand the FE point of view before I take a position for or against, and we really think things would be much more productive if everyone involved (both sides) made the same effort.
Thanks,
The RE community
Now, just in case you don't understand what the claims are being made in the posts you have quoted, please allow me to explain.
When light moves from one medium to another at an angle, and the speed of light in those two mediums is different, it refracts. This is why you observe things like rainbows, and crystals or glass that cause a rainbow on the wall when they are held up to sunlight. The different wavelengths we see in visible light behave differently in different mediums, and so when white light travels from one medium to another (say, air into glass) at an angle, these bend at different angles and the light separates into a rainbow.
When the angle is small enough, no rainbow occurs -- the magnitude of separation of the different wavelengths is small enough such that we observe only white light rather than a rainbow.
With regard to the Bedford Level experiment, it can easily and mathematically be demonstrated that a sufficient temperature gradient between the ground and the level of the measurement apparatus would cause light to bend and approximate the natural curvature of the Earth. This happens because temperature changes cause air density changes, which in turn effect the speed of light in the air. So, the air acts somewhat like a prism. 0Because no temperature measurements were made and recorded during this experiment, there is no way of verifying whether this effect was the cause of the reported measurements; however, it is important to understand also that the possibility of this effect has not been accounted for in the experiments that are generally cited by the FES.
Now it is also important to note that the bending of light under this type of circumstance is significantly different than the proposed bendiness of light required by FE theories. Most FE models of the Sun and Moon require light to bend at extreme angles over relatively short distances and under a wide variety of conditions, which is not the same as light bending at slight angles over moderate distances under very specific circumstances.