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Friday, August 5, 2016

Old Bedford Level

The Old Bedford Level

In the year 1870, one John Hampden, Esq., of Swindon published a challenge in the Scientific Opinion, Jan 12th issue which read

He will acknowledge that he has forfeited his deposit if his opponent can exhibit to the satisfaction of any intelligent referee, a convex railway, river, canal or lake.

Hampden was a student of the Flat-Earther using the alias "Parallax", who was Flat-Earther Samuel Birley Rowbotham. Rowbotham had published a 16 page pamphlet in 1849 on his Flat Earth 'theory' and later expanded into a book 'Zetetic Astronomy: Earth Not a Globe' in 1865, and later into a 430 page book in 1881.

The "Old Bedford Level" is an fairly long, straight, and almost standing body of water found between Welney Bridge and Welches Dam in England (part of the Old Bedford river) which is 31688 feet long between these two points, almost exactly 6 miles long.

Welches Dam to Welney Bridge : 31688 feet = 6.0015151... miles

Rowbothham had previously used the "Old Bedford Level" stretch to try to measure the curvature of the Earth but failed due to ignoring the effects of refraction, and so wrongly concluded that this failed experiment proved his hypothesis. Now granted, the refraction would have been very extreme at that time but this is known to happen - especially in the evening over water when there is a thermal inversion created.

This can been observed very clearly in this time-lapse by Joshua Nowicki of Chicago.

It was none other than Alfred Russel Wallace who answered his charge, thinking to make an easy £500 (but having no idea how dishonest these people would be). His choice was Bala Lake but Hampden wanted to use the Bedford Level and Wallace agreed.

Now Wallace was an experienced surveyor who was knowledgeable about refraction and how Rowbotham could have been mislead by the effects of refraction since Rowbotham had chosen to put his telescope at just 8 inches over the water.

So Wallace designed a far superior experiment which, in his words (from Wallace, A. R. 1905. My life: A record of events and opinions. London: Chapman and Hall. Volume 2.):

The experiment finally agreed upon was as follows: The iron parapet of Welney bridge was thirteen feet three inches above the water of the canal. The Old Bedford bridge, about six miles off, was of brick and somewhat higher. On this bridge I fixed a large sheet of white calico, six feet long and three feet deep, with a thick black band along the centre, the lower edge of which was the same height from the water as the parapet of Welney bridge; so that the centre of it would be as high as the line of sight of the large six-inch telescope I had brought with me. At the centre point, about three miles from each bridge, I fixed up a long pole with two red discs on it, the upper one having its centre the same height above the water as the centre of the black band and of the telescope, while the second disc was four feet lower down. It is evident that if the surface of the water is a perfectly straight line for the six miles, then the three objects—the telescope, the top disc, and the black band—being all exactly the same height above the water, the disc would be seen in the telescope projected upon the black band; whereas, if the six-mile surface of the water is convexly curved, then the top disc would appear to be decidedly higher than the black band, the amount due to the known size of the earth being five feet eight inches, which amount will be reduced a little by refraction to perhaps about five feet.
Welney Bridge

In short, Wallace argued that a convexly curved Earth would match Figure 1 -- but a Flat Earth would match Figure 2.

Now, what was seen in the first 6" telescope, which both witnesses agreed upon, was that image appeared as

This was "sketched by Mr. Coulcher and signed by Mr. Carpenter as correct".  Now remember here, the upper target and the black band are supposed to have been in a line on a flat plane (Figure 2 above).

Mr. Carpenter then objected to this on the ground that "the telescope was not levelled, and because it had no cross-hair".  Which is irrelevant as neither the level or cross-hairs can change the geometry.  But Wallace borrowed a Troughton's level, which was acceptable to Carpenter.

The sketches then made observing through this inverting telescope were exactly the same as before:

first sketch, from Welney Bridge; second, from the Old Bedford Bridge

All three sketches clearly show the highest marker as being below level (at 2) and the middle markers clearly extended well above the 'water level' marker (at 1).

This is demonstrated by Wallace's diagram where the top line from A represents level.

Of course, no amount of clear evidence would ever stop a Flat Earther so Carpenter bizarrely declared the Earth Flat on this evidence. But Walsh "decided without any hesitation that I had proved what I undertook to prove" and proceeded to publish the results and grant Wallace the winnings (which ultimately turned out to be bad due to English law who much later would void the bet).

This began a long campaign by Hampden of about fifteen years against Wallace - including Hampden threatening Wallace's life, mailing violent threats to Wallace's wife, and Hampden making numerous libelous claims against Wallace. Hampden at one point was placed in prison and had several judgments made against him.

Madam—If your infernal thief of a husband is brought home some day on a hurdle, with every bone in his head smashed to pulp, you will know the reason. Do you tell him from me he is a lying infernal thief, and as sure as his name is Wallace he never dies in his bed.
You must be a miserable wretch to be obliged to live with a convicted felon. Do not think or let him think I have done with him.
Hampden was later forced to publish retractions and repeatedly serve prison terms, but would then continue with his outright lies and liable against Wallace until his eventual death.

Mathematically speaking, over those 31688 feet we would expect an object which is at our same elevation to be about 24.0182 feet below a strictly straight-line tangent extended out from the original position..  Of course, optical sight-lines are NOT straight lines, they are warped and distorted by small changes in the refractive index of the air.  Wallace observed about 22 feet of drop below the exact level point - which left about 2 feet which was likely due to a combination of refraction and measurement error.

But even this doesn't deter Flat Earthers from designing experiments which continue to ignore refraction and continue to give false results and reports as a result.

Perhaps they will never learn...

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