[inquisitive]

Samuel Birley Rowbotham studied that very topic in his work Earth Not a Globe. Take a look at his eye level and horizon experiments in Chapter 2, as well as his theodolite experiments.

Interesting that you choose to ignore details of professional surveying equipment.

[Tom Bishop]

Sorry, he used 4, there's one on the camera too. And here's that Bobby experiment with no water tubes, if you like that method better.

I missed this one  This experiment is addressed by Rowbotham:

http://www.sacred-texts.com/earth/za/za32.htm

The error in perspective, which is almost universally committed, consists in causing lines dissimilarly distant from the eye-line to converge to one and the same vanishing point. Whereas it is demonstrable that lines most distant from an eye-line must of necessity converge less rapidly, and must be carried further over the eye-line before they meet it at the angle one minute, which constitutes the vanishing point.

...

The theory which affirms that all parallel lines converge to one and the same point on the eye-line, is an error. It is true only of lines equi-distant from the eye-line; lines more or less apart meet the eye-line at different distances, and the point at which they meet is that only where each forms the angle of one minute of a degree, or such other angular measure as may be decided upon as the vanishing point. This is the true law of perspective as shown by nature herself; any idea to the contrary is fallacious, and will deceive whoever may hold and apply it to practice.

Notice that some of the line overlays seem forced in Bobby's picture. They don't all point to the same place, but slightly different places.

Also possibly related to the water leveling issues.

Rowbotham has a few correct ways to determine eye  level, which he describes in Earth Not a Globe

[stack]

Sorry, he used 4, there's one on the camera too. And here's that Bobby experiment with no water tubes, if you like that method better.

I missed this one  This experiment is addressed by Rowbotham:

http://www.sacred-texts.com/earth/za/za32.htm

The error in perspective, which is almost universally committed, consists in causing lines dissimilarly distant from the eye-line to converge to one and the same vanishing point. Whereas it is demonstrable that lines most distant from an eye-line must of necessity converge less rapidly, and must be carried further over the eye-line before they meet it at the angle one minute, which constitutes the vanishing point.

...

The theory which affirms that all parallel lines converge to one and the same point on the eye-line, is an error. It is true only of lines equi-distant from the eye-line; lines more or less apart meet the eye-line at different distances, and the point at which they meet is that only where each forms the angle of one minute of a degree, or such other angular measure as may be decided upon as the vanishing point. This is the true law of perspective as shown by nature herself; any idea to the contrary is fallacious, and will deceive whoever may hold and apply it to practice.

Notice that some of the line overlays seem forced in Bobby's picture. They don't all point to the same place, but slightly different places.

Also possibly related to the water leveling issues.

Rowbotham has a few correct ways to determine eye  level, which he describes in Earth Not a Globe

Nope, this is from CHAPTER XIV, WHY A SHIP'S HULL DISAPPEARS BEFORE THE MAST-HEAD

We're not talking about vanishing points like looking down a railroad track. This is looking across the horizon and how it dips with elevation and does not meet the eye line.

There are no water leveling issues, they are strings. If you're talking about the spirit level inside the cage are you saying spirit levels have no control and should not be used?

If Rowbotham had a few ways to determine eye level, cite them and cite the chapter and verse so I don't have to keyword search through ENAG for the thousandth time only to find a completely irrelevant quote provided by you.

[TomFoolery]

Regardless of whether the horizon is at eye level or not in all circumstances, the experiments used are not even methods that surveyors use. The people doing this experiment are basically just making up surveying science as they go along.

The tool needs to be calibrated. The experiment needs a control. Assuming that it is level or that it is an accurate method is not enough.

Well Dr. Bishop I am so glad to hear you say that. Yes. A method that surveyors use. I like the way you are thinking.
I recently purchased off of ebay a Pentax ETH-20F Digital Theodolite. I'm not talking about a silly cell phone app, I'm talking about a real surveyor's digital theodolite.
I've been learning how to use it off you tube, I calibrated it, and everything. It has a built in calibration routine. It has a resolution of 20 arcseconds.

Is that the kind of equipment you're thinking of?

I can measure all sorts of things with this, not only the dip of the horizon, but the dip of ships and mountains too! Ya?

I never mentioned too much about it because well I figured since you don't even think water seeks it's own level (even though you know how a water level works) I figured that you probably would inherently question my gizmo since you may not understand it's internal workings quite as well as you do a water level.

In any case, the experiment should be calibrated and controlled for validity.

How do you calibrate a water level, there Doc?
Just honestly curious as to how you might calibrate a water level if it wasn't reading level. Maybe add water to one end?

The device and underlying theory may be totally off in application. It's making a lot of assumptions about perspective, water tension, refraction, etc. The fact that it can't be calibrated shows the issue. We need a way to gauge how accurate it is.

Oh that's right. It's Dr. "450PPM is too much error to consider the reading valid." Even though the water level showed an internal error of less than a percent of the height of the horizon even at 100ft elevation, it can't be trusted because it's not exactly accurate to zero parts in thirty trillion.

Do you *really* think the water was an inch higher in one end as compared to the center?

This experiment has not been proven to be valid or accurate, or have any bearing on anything at all. It is not used in surveying or for any purpose. The principles need to be demonstrated.

Which experiment has not been proven valid? Oh, that water seeks it's own level? and the fact that water seeks its own level has no bearing on anything at all?
Oh, and I think it is used in primitive surveying, but someone already posted the video so I didn't.

Last year a caged water device was built by a member of our forums, which showed that the alignment of the liquid in the device is susceptible to error. It was seen that the liquid did not align and that water did not find its level.

The water levels did not line up to each other in relation to the plumb line.

Hmm. Looking closely, I see that the pictures were taken at a close distance with a wide angle lens. Notice how the left tube in some of the pictures appears so much thicker?
The camera lens quite likely distorted the picture and the cage may not have been level and the camera may have been adjusted to line up with the cage.

Rowbotham has a few correct ways to determine eye  level, which he describes in Earth Not a Globe

Excellent! Have you tried one of them? which one? Or which would you recommend as the best tool for measuring eye-level?

EDIT: Meant to include this one too:
Don't play the video, just look at the thumbnail: Methinks the open ended clear tubes are cut at different angles and catch the wind differently, creating pressure differences.
OK Fine play the video and hear the wind shearing turbulence across the mic. Sounds like it was a pretty constant steady wind.

The matter has already been impeached. The inability to calibrate the three chamber version of the device is direct evidence that the water is not level.

[AATW]

Samuel Birley Rowbotham studied that very topic in his work Earth Not a Globe. Take a look at his eye level and horizon experiments in Chapter 2, as well as his theodolite experiments.

Are those the experiments where he said that at very low altitude - I think he used a pier and hotel (with about 6 stories) - the horizon is at eye level. Which it more or less is.
And then when he got a result of horizon dip at altitude he started blaming the equipment. Laughable.

It always amuses me that your Wiki page on this matter only contains one account of an observation at altitude eye level which doesn't say any measuring devices were used and says the horizon was "practically" at eye level. And your example is a 3D game. Are you expecting any of this to be taken seriously?! 

I still you're still squirming despite multiple methods showing the same result. And you're still refusing to do your own tests. We all know why...

[QED]

The matter has already been impeached. The inability to calibrate the three chamber version of the device is direct evidence that the water is not level.



Last year a caged water device was built by a member of our forums, which showed that the alignment of the liquid in the device is susceptible to error. It was seen that the liquid did not align and that water did not find its level.

https://forum.tfes.org/index.php?topic=9492.280



The water levels did not line up to each other in relation to the plumb line.

The burden to show these devices as valid is absolutely on those who champion it.

A small error in the foreground can cause a very large error many miles away.



Again, if you are championing these devices then it is your responsibility to show that they are accurate. Ignoring direct evidence is not acceptable.

Surveying is not an accurate science by its very nature. The idea that someone can create surveying tools without the need to calibrate it or test it for accuracy is quite rediculous.

http://whistleralley.com/surveying/theoerror/

As any surveyor should understand, all measurements are in error. We try to minimize error and calculate reasonable tolerances, but error will always be there. Not occasionally; not frequently; always. In the interest of more accurate measurements, we look for better instruments and better procedures.
—Paul Kunkel

Are you a surveyor? Do you know better than the surveyors who tell us that surveying is always in error? Are we to believe that amateurs created superior surveying equipment that can accurately test the horizon, the furthest thing that can be tested in surveying?

No, that is absurd. Once again, the burden is entirely on those who champion the device to demonstrate its validity.

The matter is not impeached simply because you can reference a YouTube video, or can find a alternate device which was faulty, or can provide a quotation about surveying from an obviously biased source.

I am beginning to become concerned about the negative influence you present for the FE community. Here we have a group of individuals with a common focus, with many of them potentially in a position to contribute positively towards that focus’ goal.

You do not appear to be steering them in a positive fashion. Your address of evidence is inconsistent, and the standards you apply to claims made by Rowbotham are entirely different than those made by others.

This inconsistency of standard and failure to champion a honest scientific inquiry is detrimental to FE efforts. Through your example, FE efforts are marginalized and hampered.

Perhaps the FE community would benefit from a new figure to guide them into the arena of legitimate scientific research. Someone who understands the scientific method, and can unbiasely apply standards of evidence. Someone who does not make amateur errors in mathematics, and does not lack knowledge of the fundamental structures which exist in competing theories.

I seriously question whether you can fill this need.

[Tom Bishop]

The matter is not impeached simply because you can reference a YouTube video, or can find a alternate device which was faulty, or can provide a quotation about surveying from an obviously biased source.

Actually, it is. These people put their devices under a little scrutiny, and found that they were imperfect. Why should we assume that the people who did not put their devices under scrutiny are perfect? If some devices were found to be imperfect, then anyone doing this experiment should scrutinize their tools as well.

Obviously biased? Is the surveyor quoted a flat earther?

We must always ensure that our tools are accurate for the job. The fact that anyone could think that we do not need to ensure accuracy says volumes. I find your argument that testing for accuracy is not needed to be totally invalid.

It may be that the horizon does drop at higher altitudes for various reasons, but this tool may be unreliable to show us exactly where eye level is.

[AATW]

Fairly reasonable point.
The issue is you don’t put experiments which confirm your world view under any scrutiny at all.
Only experiments which contradict your beliefs (which are mostly based on your high priest Rowbotham’s) are scrutinised to death.
It’s confirmation bias writ large.

And all the while you refuse to do any tests yourself.

Again, if the issues with these experiments were ones of configuration you’d get a variety of results. Your own diagram about the meniscus showed that - the error could be in either direction. That isn’t what is observed. Every test shows consistent results:
Horizon dips below eye level.
The amount of dip increases with altitude.

This is consistent with several other methods to test this which also show these results.

It’s notable that your objections keep changing. In other threads you flailed around questioning all kinds of things, desperately trying to cast some doubt on the results. Anything other than change your views. These are not the actions of someone seriously seeking truth, it’s more like religious fanaticism.

If you think these experiments are all in error and all in error in the same way the feel free to devise and conduct your own tests and publish the results. Try it. You might learn something. If you want to...

[Tom Bishop]

The experiment is subject to a number of possible systematic issues. For one thing, the experimenters are using colored water, which makes it difficult to see if the surface is level or not. The full upper surface is seen when the eye is above the water column, but when the column is above the eye one can't easily see through the colored water to see if it's level or not. This makes it more likely to be too high than too low.



Another issue is that they are aligning the upper surface, which is not level. From Encyclopedia Brittanica:



From p.4:





If we were to tilt the device, lowering down the bottom lip of the background container to match the bottom lip of the foreground device, we can clearly see that it would be a different result.

[stack]

The experiment is subject to a number of possible systematic issues. For one thing, the experimenters are using colored water, which makes it difficult to see if the surface is level or not. The full upper surface is seen when the eye is above the water column, but when the column is above the eye one can't easily see through the colored water to see if it's level or not. This makes it more likely to be too high than too low.

Or this:

If we were to tilt the device, lifting the bottom lip of the water level in the foreground device up to match the bottom lip of the background device, it would be a different result.

Then don't go randomly tilting it. Use a spirit level as a control.

[Tom Bishop]

In the case of the above device, it is questionable whether the front container is even level. There is a lip of lightness at the top, like we are looking down at it. In the case of the colored water, the upper surface might be entirely black, missing cues like this.

The thick meniscus in these devices cause the same issues as the colored water does. Questionable calibration and alignment. Steps to ensure accuracy are desired.

[QED]

The matter is not impeached simply because you can reference a YouTube video, or can find a alternate device which was faulty, or can provide a quotation about surveying from an obviously biased source.

Actually, it is. These people put their devices under a little scrutiny, and found that they were imperfect. Why should we assume that the people who did not put their devices under scrutiny are perfect? If some devices were found to be imperfect, then anyone doing this experiment should scrutinize their tools as well.

Obviously biased? Is the surveyor quoted a flat earther?

We must always ensure that our tools are accurate for the job. The fact that anyone could think that we do not need to ensure accuracy says volumes. I find your argument that testing for accuracy is not needed to be totally invalid.

It may be that the horizon does drop at higher altitudes for various reasons, but this tool may be unreliable to show us exactly where eye level is.

Scrutiny which lacks rigorous application returns unscientific results. The proposed method of failure cannot possibly influence the measurement due to the difference in scale between its effect and the measurement.

It is certainly possible that these experiments are inaccurate. Nevertheless, your present method of inquiry will not tell you so. This is because that method is fallacious reasoning, YouTube videos, and cartoon drawings, which you have somehow confused with science.

[stack]

In the case of the above device, it is questionable whether the front container is even level. There is a lip of lightness at the top, like we are looking down at it. In the case of the colored water, the upper surface might be entirely black, missing cues like this.

The thick meniscus in these devices cause the same issues as the colored water does. Questionable calibration and alignment. Steps to ensure accuracy are desired.

Rowbotham’s ENAG Experiment 11

"Another proof will be found in the following experiment. Select any promontory, pier, lighthouse gallery, or small island, and, at a considerable altitude, place a smooth block of wood or stone of any magnitude; let this be "levelled." If, then, the observer will place his eye close to the block, and look along its surface towards the sea, he will find that the line of sight will touch the distant horizon. Now let any number of spirit levels or theodolites be properly placed, and accurately adjusted; and it will be found that, in every one of them, the same sea horizon will appear in the field of view considerably below the cross-hair; thus, proving that telescopic instrumental readings are not the same as those of the naked eye.”

So this is essentially the kind of control, alignment, and calibrated rigor you’re looking for: placing one’s eye close to the block? Then comparing that to the accuracy of a locked down leveled and stationary theodolite? And then coming to the insanely obvious conclusion that "telescopic instrumental readings are not the same as those of the naked eye”? This is the type of solid experimentation you demand? Nose to a block of wood? Certainly no questionable calibration and alignment there...Seriously?

So I guess we’ll forget tubes/bottles of water and string cages, we’ll just move to eyeballing it with planks of wood. Is that acceptable?

[TomFoolery]

In the case of the above device, it is questionable whether the front container is even level. There is a lip of lightness at the top, like we are looking down at it. In the case of the colored water, the upper surface might be entirely black, missing cues like this.

The thick meniscus in these devices cause the same issues as the colored water does. Questionable calibration and alignment. Steps to ensure accuracy are desired.

So, Mr. Bishop, what technique would you use to check whether the horizon rises to eyelevel of the observer?

[inquisitive]

In the case of the above device, it is questionable whether the front container is even level. There is a lip of lightness at the top, like we are looking down at it. In the case of the colored water, the upper surface might be entirely black, missing cues like this.

The thick meniscus in these devices cause the same issues as the colored water does. Questionable calibration and alignment. Steps to ensure accuracy are desired.

You have ignored details of a device with specified accuuracy and calibation that I provided.  Why?

[Max_Almond]

Lol @ this thread. We feed the troll, the troll grows bigger.

What do those blue lines even mean? They have to be at the level of the water, Tom can't just draw them arbitrarily wherever he feels like.

Boys, our minds are like pearls, our intellects holy - and we all know what the good Lord JC said not to do with holy things and pearls, right?

Though I can't say I haven't been guilty of it myself.

He knew a thing or two, that JC.

[AATW]

Indeed. I don't think this is worthy of further debate until Tom does his own tests and publishes the results and his method for review.
Until then it's just him windmilling his arms and shouting "doesn't, doesn't, doesn't" when shown the horizon dip result which is not a very productive discussion.

The fact he refuses to do any tests himself is telling...

[Bikini Polaris]

Indeed. I don't think this is worthy of further debate until Tom does his own tests and publishes the results and his method for review.

Apparently it's pointless to ask such questions as "what is the best tool for..." or ask for results, because the "zetetic method" denies trust to peers and force their followers to personally reproduce their experiments. It's up to a zeteticist to trust or not its own experiment and live on his own conclusions. On the other side the scientific method, that is quite misunderstood by Tom Bishop, is ultimately based on giving the best possible answer with the best possible tool and reducing the chance to be wrong, but that probability cannot, and never will, be zero. Actually, the study of measurement error you'll always have in any device is the very first step in any science course. Any scientist knows that any conclusion he'll take is true up to his measurement error. And this is good, because it creates a community where everyone will accept as truer the measurements taken with the best instruments! I cannot see bacteria with my own eyes, but someone with a microscope did and that becomes the leading hp!

[Macarios]

I love how some posts in this thread go against one of the Rowbotham's cornerstones: "water is always level".

In every pipe you have capillary effect next to the walls. But the middle of wide enough pipes are always horizontal.
Decide how narrow a pipe should be to have capillary effect dominant?
Then for making water level use much wider pipes and solve the problem.
Ofcourse, use the pipes of equal diameter and have the capillary action balanced in both.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~



Examples: for a 0.2 m (0.66 ft) radius glass tube in lab conditions given above, the water would rise an unnoticeable 0.07 mm (0.0028 in).
For a 2 cm (0.79 in) radius tube, the water would rise 0.7 mm (0.028 in).
For a 2 mm (0.079 in) radius tube, the water would rise 7 mm (0.28 in).

So, say, use two equal pipes with radius of 3 cm and you will have meniscus height of 0.49 mm equal in both.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

EDIT:

By the way, perspective is also doing this, but Rowbotham skips that part:

[flachland]

To get roughly near, some cameras have a level display. For example Sony A7, A7r etc. Very useful when you take landscape images.