13 “In a 19th century French experiment by M. M. Biot and Arago a powerful lamp with good reflectors was placed on the summit of Desierto las Palmas in Spain and able to be seen all the way from Camprey on the Island of Iviza. Since the elevation of the two points were identical and the distance between covered nearly 100 miles, if Earth were a ball 25,000 miles in circumference, the light should have been more than 6600 feet, a mile and a quarter, below the line of sight!”

Hurray – a new point at last. Unfortunately… it makes little sense, because the numbers quoted are wrong.

First, a reference for this to a real science publication would help to check on the decidedly dodgy figures claimed.

Mr Dubay does not provide the elevation of the two points. It seems the height of the summit of Desierto de las Palmas is: 729 meters, or 2390 feet at Bartolo peak.

There is nowhere on the island of Ibiza that is particularly close to being 2390 feet high as the highest point on the island, Sa Talaiassa, is 475 meters, or 1558 feet, high. Oops, Mr Dubay has a real problem with facts.

The apparent source for this claim, Zetetic Astronomy Samuel Birley Rowbotham (1816–1884) seems to have messed up the mathematics more than somewhat.

See the following for more details and diagrams:

http://the-uncredibles.tumblr.com/post/130511368809/200-pensb-13-biot-and-arago-experiment

Stop Press! Dubay and his sources amazingly wrong again!

Since I posted the reply above, I've seen this, showing that almost everything in the claim is wrong. What a surprise...:

SPOILER ALERT: This post is very boring, and mostly pointless: not even flat earthers use this 'proof', and Dubay seems to have gone somewhat out of fashion, but I include it here because: a) I did the research already; b) others debunking his list on their blogs hadn't quite figured this one out; c) it's maybe good that it exists somewhere; and d) it's a great example of how Dubay has compiled, presented, and (not) researched his material.

So...

At number 13 in his list (video/self-published book/website) of "200 Proofs the Earth is not a Spinning Ball", Dubay says that:

"In a 19th century French experiment by M. M. Biot and Arago a powerful lamp with good reflectors was placed on the summit of Desierto las Palmas in Spain and able to be seen all the way from Camprey on the Island of Iviza. Since the elevation of the two points were identical and the distance between covered nearly 100 miles, if Earth were a ball 25,000 miles in circumference, the light should have been more than 6600 feet, a mile and a quarter, below the line of sight!"

Content from external source

As usual, this is a fairly direct quotation from one of the Victorian flat earth texts, this time Samuel Rowbotham's "Earth Not a Globe" (1872):

https://books.google.com.mx/books?id=VeBivA6QSEUC&pg=PT47&lpg=PT47&dq=rowbotham+biot+arago&source=bl&ots=2aR3V-9udm&sig=987ij9hMEVA5TGHe_h8H4U2I85o&hl=en&sa=X&ved=0ahUKEwis1Z3Z7bnOAhUG2WMKHbVZDjYQ6AEIKzAD#v=snippet&q="In the account of the trigonometrical operations"&f=false

"In the account of the trigonometrical operations in France, by M. M. Biot and Arago, it is stated that the light of a powerful lamp, with good reflectors, was placed on a rocky summit, in Spain, called Desierto las Palmas, and was distinctly seen from Camprey, on the Island of Iviza. The elevation of the two points was nearly the same, and the distance between them nearly 100 miles. If the earth is a globe, the light on the rock in Spain would have been more than 6600 feet, or nearly one mile and a quarter, below the line of sight."

Content from external source

POINT 1: While almost repeated word-for-word, there are a few important changes to note. First of all, Dubay has chosen to call the "trigonometrical operations" a "French experiment" - probably to make it look like a flat earth test rather than the measuring of the globe that it actually was - and, rather than Rowbotham's "nearly the same" elevation of the two points, he has claimed they were "identical." This is a pretty amusing assertion, given neither he nor Rowbotham knew where the points actually were.

POINT 2: Another fun one. When reading the text out, he says, "M. M. Biot", as though these were the guy's initials. "MM." actually means "messieurs" - ie, "Misters Biot and Arago." Biot's first name was Jean-Baptiste.

TITBIT 1: Biot and Arago were two French physicists, astronomers, and mathematicians - and certainly not flat earthers - who, in 1806, took on the work of measuring the meridian arc which passes through Paris in order to determine the exact length of a metre. It was a pretty Herculean and adventurous task, taking many years and involved scaling mountains, being arrested as spies, and subsequent escapes from the Spanish authorities. Quite the dedication to science!

POINT 3: The Desierto de las Palmas is a mountain range in the Spanish province of Castellón. The highest peak is called Bartolo, and it is from here that Biot and Arago made their measurements, as recorded on page 20 of "Memorial du Depot General de la Guerre, Volume 7". The elevations given are between 726.36 metres and 728.29 metres (2383 and 2389 feet).

This demonstrates that Rowbotham clearly had no idea of the elevation of the summit of Desierto de las Palmas, since it would be impossible for the two points to be "nearly the same" - the highest point on Ibiza is 1558 feet, and this wasn't the point Biot and Arago were using.

TITBIT 2: From "Report of Observations Geodesic, Astronomical, and Physics" by MM. Biot and Arago (1821):

https://books.google.com.mx/books?id=3iYyAQAAMAAJ&pg=PA79&lpg=PA79&dq=observations+geodesiques+desierto+de+las+palmas&source=bl&ots=JgkxN7VeTq&sig=2LZulESyPdx7gR085a0GWsfRhqc&hl=en&sa=X&ved=0ahUKEwjcppuFirrOAhVCKGMKHRN8BqsQ6AEIHTAA#v=onepage&q=observations geodesiques desierto de las palmas&f=false

The Desierto de Las Palmas is a mountain located in the Kingdom of Valencia, on the edge of the sea, between Oropesa and Castellon de la Plana, above the village of Bennicassim. At its highest peak is a small hermitage that can be seen from afar. M. Mechain had chosen this point for one of the peaks of the large triangle which was to end on Yvice (Ibiza) across the sea; accordingly we established our station near the hermitage. Thus, with greater ease in operating, we got the advantage of extending the arc of the meridian to the small island of Formentera, about twenty-five minutes further south than we could have done following the first combinations.

Content from external source

POINT 4: While Biot and Arago called the point on Iviza (Ibiza) "Campvey", Dubay copies Rowbotham in calling it "Camprey": presumably because the original publication's "v" looks a little like an "r". Either way, I wasn't able to locate anywhere called Camprey or Campvey on Ibiza now - though, oddly, it shows up on some German sites as an Ibizan peak with an elevation of 396 metres. Handily, this matches the elevation reported by Biot and Arago, on page 9 of the aforementioned "Memorial du Depot" (and elsewhere), making it a good 1090 feet below the summit of Bartolo - ie, not exactly "identical."

Using the metabunk curve calculator, and a distance of 100 miles (Rowbotham got that much right) this shows us that at least 224 feet of Campvey should have been visible from Bartolo.

Claim #13, therefore, is debunked.



FURTHER QUESTIONS

1. Where is Campvey exactly? A topo map of Ibiza locating a peak of 396 metres/1299 feet about 100 miles from Bartolo should do it.

Or, in the aforementioned primary sources, latitude and longitude are given for Bartolo as 44.54/+2.56 and Campvey as 43.4/+1.09, but I can't work out what these refer to. Did they have a different system back then? After all, these measurements were taken a good 70 years before the prime meridian was established

2. In the 1870 edition (Volume 7, 4th Series) of "Chambers's Journal of Popular Literature, Science and Arts" the story of Biot and Arago is told, and it's possible this is where Rowbotham took his information, given that he uses the journal in some of his other 'proofs'. The Chambers account seems fairly scientific and straightforward, though, but I can't read all of it, as the digitised google books version isn't available in full-view.

3. Will I do research like this on any more of Dubay's 'proofs'? Hell no! Thorough investigation of this and "#4: Rivers Flow Uphill" (link to metabunk thread) - plus glances at some of the others - has told me pretty much everything I need to know. Hopefully the same can be said for any other sane-thinking person too.

Sorry for the tedium! 

From Debunked: Eric Dubay "Flat Earth Proof" #13

https://www.metabunk.org/debunked-eric-dubay-flat-earth-proof-13.t7827/

7) “Surveyors, engineers and architects are never required to factor the supposed curvature of the Earth into their projects. Canals, railways, bridges and tunnels for example are always cut and laid horizontally, often over hundreds of miles without any allowance for curvature.”

When it matters, on large-scale projects, engineers do always take account of the earth’s curvature.

Here is one example where they did exactly that, because such precision mattered. 

Look at:

https://www.metabunk.org/attachments/slac-png.17136/

Read more at;

http://www.slac.stanford.edu/econf/C06092511/presents/TU004_PPT.PDF
and search for the word “curvature”.

And more such documents here;
http://www-psearch.slac.stanford.edu/SLACSearch/app/slac/index?style=mainSite&qt=earth%20curvature

And another example:  When designing the Humber Bridge “the towers, although both vertical, are 34 mm (1.3 inches) farther apart at the top than the bottom due to the curvature of the earth  

https://en.wikipedia.org/wiki/Humber_Bridge

And for a bit of fun, here is an example where engineers forgot the curvature:
https://www.metabunk.org/what-happened-when-engineers-forgot-the-earth-was-round.t8990/#post-209322

If Dubay was right, that wouldn't have mattered. But as you'll see it did, showing that Dubay is very wrong, again.

Here is a technical note for Swiss surveyors telling them how to take account of the earth's curvature..

And another from the USA, 

And here is another one.

And a book.

And another book

It looks like surveyors do take account of the curve, and Mr Dubay doesn’t know what he is talking about.  Again.

To reject this evidence you have to believe that

a) All of these many documents, and the huge number of similar ones around the world, are faked simply in case someone might happen to look at them, and also

b) None of the engineers and architects who have used them in practice have complained when they found that the 'faked' information didn't work. Are they all part of the 'conspiracy'?

And from the 19th century, where Dubay's claim comes from:

Given that some people claim the curvature of the Earth is not accounted for in surveying, I thought it would be interesting to document various historical instances of this, and of accounting for refraction.

Curvature comes up in two ways. Firstly it arises when determining latitude and longitude by observation of sun and stars. The Earth here is assumed to be a sphere, and the stars essentially fixed in a "celestial sphere" infinitely far away.

Secondly it comes up in the practice of levelling which is the art of determining how high things are above a nominal level surface, such as the surface of the sea. Interestingly this use of the word "level" is often misinterpreted as meaning "flat", when the books on surveying make quite clear this is not the case.

...

And of course "history" extends up to the present day. I don't want people to get the idea that this is some archaic technique. The shape of the Earth has not significantly changed in the last 200 years, nor has atmospheric refraction. So the same numbers still apply.

Here's a course in surveying leveling from Fresno State Lyles College of Engineering:

For many more examples of engineer describe, for other engineers, how and why they need to take account of the curved earth, read on here: https://www.metabunk.org/curvature-and-refraction-in-surveying-and-leveling-through-history-old-books-etc.t8856/#post-207664

For yet more information debunking Dubay read this.

It isn't just Dubay who misleads us

Jaranism is another Flat earther who is very inclined to make false stements.

For example, here is his FAQ section he quotes some lecture notes for surveyors to support the same flase claim, that surveyors and engineers never take the earth curvature into account:

You would think that a surveyor, one who is attempting to retrieve the most accurate results of the ground they are surveying, would have to adjust for or take into account, the curvature of the earth. This is simply not how it is done. Notice to begin chapter 2 below… it states that most surveying activities are performed with the pseudo assumption that measurements are being made with reference to a flat horizontal surface.

But here is the very next page, his own source disproves his claim:

https://www.cartercenter.org/resour...tes/env_health_science_students/surveying.pdf


Jeranism can't possibly have missed this, can her? He must be misleading us on purpose, or so it seems.

(Thanks to Mick West for this link)