[edby]

Rowbotham says

The distance across St. George's Channel, between Holyhead and Kingstown Harbour, near Dublin, is at least 60 statute miles. It is not an uncommon thing for passengers to notice, when in, and for a considerable distance beyond the centre of the Channel, the Light on Holyhead Pier, and the Poolbeg Light in Dublin Bay, as shown in fig. 23.

And he explains

The Lighthouse on Holyhead Pier shows a red light at an elevation of 44 feet above high water; and the Poolbeg Lighthouse exhibits two bright lights at an altitude of 68 feet; so that a vessel in the middle of the Channel would be 30 miles from each light; and allowing the observer to be on deck, and 24 feet above the water, the horizon on a globe would be 6 miles away. Deducting 6 miles from 30, the distance from the horizon to Holyhead, on the one hand, and to Dublin Bay on the other, would be 24 miles. The square of 24, multiplied by 8 inches, shows a declination of 384 feet. The altitude of the lights in Poolbeg Lighthouse is 68 feet; and of the red light on Holyhead Pier, 44 feet. Hence, if the earth were a globe, the former would always be 316 feet and the latter 340 feet below the horizon, as seen in the following diagram, fig. 24. The line of sight H, S, would be a tangent touching the horizon at H, and passing more than 300 feet over the top of each lighthouse.

Many instances could be given of lights being visible at sea for distances which would be utterly impossible upon a globular surface of 25,000 miles in circumference. (etc)

Taking the second part first. The curve calculator agrees that the horizon would be 6 miles distant, and the calculation for the hidden amount given 30 miles with the observer 24 feet above water is 384 feet. So science agrees with Rowbotham on what science says.

However his first claim is that ‘it is not an uncommon thing’ (giving no source) for observers to see the harbour lights at both directions, which is impossible according to science. So is the earth really flat then?

However, this source disagrees, noting the publication ‘Sailing directions for the coast of Ireland. Part I’, 1877, compiled by Staff Commander Richard Hoskin of the Royal Navy from various Admiralty surveys.

Poolbeg Light. - A white tower on the east end of the south wall at the entrance of the river Liffey, exhibits one fixed white light at an elevation of 68 feet above high water, visible 12 miles.

My emphasis. Of course it is theoretically possible that the Admiralty document, published as a guide to help navigators safely move from harbour to harbour, was deliberately designed to lure sailors to their death, but why would it do that? It is also theoretically possible that Rowbotham was making the whole thing up. Who can say?

A simple investigation could resolve the matter.

[Tom Bishop]

If one source says that a lighthouse is visible when 30 miles away, why isn't it possible for another source to say that a light house is visible when at 12 miles away?

That source does not even specify that 12 miles is the limit, only that it was seen. And, even if it did, which I cannot find specified, there is such a thing as marine fog and atmospheric conditions that can regularly obscure.

[edby]

If one source says that a lighthouse is visible when 30 miles away, why isn't it possible for another source to say that a light house is visible when at 12 miles away?

That source does not even specify that 12 miles is the limit, only that it was seen. And, even if it did, which I cannot find specified, there is such a thing as marine fog and atmospheric conditions that can regularly obscure.

My understanding is that visible range refers to maximum visible range (otherwise there would be no point in publishing it).

Note also this:

When first sighting a light, an observer can determine if it is on the horizon by immediately reducing his height of eye. If the light disappears and then reappears when the observer returns to his original height, the light is on the horizon. This process is called bobbing a light.

Why would changing the observer's height cause the light to appear and disappear?

[edby]

You might also look up the concept of 'geographic range', which is a navigational concept, meaning precisely the maximum range a light is visible.

If you can also 'bob the light', it means you are at geographic range.

Here is a neat video. Warning: the instructor assumes 'as we all know', that the earth is round. But this is only 'the practical experience of nautical men', as Rowbotham says.

[Tom Bishop]

If one source says that a lighthouse is visible when 30 miles away, why isn't it possible for another source to say that a light house is visible when at 12 miles away?

That source does not even specify that 12 miles is the limit, only that it was seen. And, even if it did, which I cannot find specified, there is such a thing as marine fog and atmospheric conditions that can regularly obscure.

My understanding is that visible range refers to maximum visible range (otherwise there would be no point in publishing it).

Note also this:

When first sighting a light, an observer can determine if it is on the horizon by immediately reducing his height of eye. If the light disappears and then reappears when the observer returns to his original height, the light is on the horizon. This process is called bobbing a light.

Why would changing the observer's height cause the light to appear and disappear?

It just says visible, not visible range.

Regardless, 30 miles is pretty far away. When looking out on the ocean it is not uncommon for the marine layer to build up.

Rowbotham doesn't say that the lighthouse is always visible, only that it and others like it have been seen at those ranges and that people were speculating about refraction to explain it.

The 12 mile source seems ambiguous in exactly what it's talking about or how it was determined, but if it did imply range, it would not be surprising if a book listed a shorter distance for it's visible range, rather than publishing a range that some people have seen it from. The purpose would be to give information to sailors on what they could expect to see.

[edby]

It just says visible, not visible range.

Regardless, 30 miles is pretty far away. When looking out on the ocean it is not uncommon for the marine layer to build up.

Rowbotham doesn't say that the lighthouse is always visible, only that it and others like it have been seen at those ranges and that people were speculating about refraction to explain it.

It would not be surprising if a book listed a shorter distance for it's visible range, rather than publishing a range that some people have seen it from. The purpose would be to give information to sailors on what they could expect to see.

I recommend you watch the instructional video above. These things are not written down just for fun.

You might also be interested in the range table at t = 219.

[Tom Bishop]

It just says visible, not visible range.

Regardless, 30 miles is pretty far away. When looking out on the ocean it is not uncommon for the marine layer to build up.

Rowbotham doesn't say that the lighthouse is always visible, only that it and others like it have been seen at those ranges and that people were speculating about refraction to explain it.

It would not be surprising if a book listed a shorter distance for it's visible range, rather than publishing a range that some people have seen it from. The purpose would be to give information to sailors on what they could expect to see.

I recommend you watch the instructional video above. These things are not written down just for fun.

You might also be interested in the range table at t = 219.

https://youtu.be/lO-oUm4f84E?t=219

I took a brief look at the video. It appears that he is just encouraging the use of the theoretical Round Earth model on paper to determine a range, rather than testing it in real life.

How do we know that this wasn't the same method used in the source you quoted for the shorter range? What you posted seems more discrediting to the shorter range argument, if that is the method used.

[edby]

I took a brief look at the video. It appears that he is just encouraging the use of the theoretical Round Earth model on paper to determine a range

That's right. I assume, as a marine instructor, he knows what he is talking about.

In fact, applying that table to Rowbotham's example, I get 6.7 statute miles for the visible range of the boat at 24 feet height, plus 11.3 miles for the 68 feet of the lighthouse, giving a total maximum distance of 18 miles.

So Rowbotham's figure of 30 statute miles is way off. I wonder if he was just making this up? Do have evidence he was telling the truth?

rather than testing it in real life.

He is teaching people who will 'test it in real life' in circumstances that will hopefully save their life!

[edby]

Northeastern Maritime Institute.

I suggest he is using textbooks which teach heuristics (rules of thumb) which have long passed the test of time by 'practical seafaring men'.

[Tom Bishop]

I took a brief look at the video. It appears that he is just encouraging the use of the theoretical Round Earth model on paper to determine a range

That's right. I assume, as a marine instructor, he knows what he is talking about.

In fact, applying that table to Rowbotham's example, I get 6.7 statute miles for the visible range of the boat at 24 feet height, plus 11.3 miles for the 68 feet of the lighthouse, giving a total maximum distance of 18 miles.

So Rowbotham's figure of 30 statute miles is way off. I wonder if he was just making this up? Do have evidence he was telling the truth?

Rowbotham and Co. took their information from credible sources of the day. Dubey writes about the matter:

---

A copy of the book “The Lighthouses of the World” and a calculator are enough to prove that the Earth is not a globe, but an extended flat plane. The distance from which various lighthouse lights around the world are visible at sea far exceeds what could be found on a globe Earth 25,000 miles in circumference. For example, the Dunkerque Light in southern France at an altitude of 194 feet is visible from 28 miles away. Spherical trigonometry dictates that if the Earth was a globe with the given curvature of 8 inches per mile squared, this light should be hidden 190 feet below the horizon!

The Port Nicholson Light in New Zealand is 420 feet above sea-level and visible from 35 miles away which means it should be 220 feet below the horizon. The Egerö Light in Norway is 154 feet above high-water and visible from 28 statute miles where it should be 230 feet below the horizon. The Light at Madras, on the Esplanade, is 132 feet high and visible from 28 miles away, where it should be 250 feet below the line of sight. The Cordonan Light on the west coast of France is 207 feet high and visible from 31 miles away, putting it 280 feet below the line of sight. The light at Cape Bonavista, Newfoundland is 150 feet above sea-level and visible at 35 miles, where it should be 491 feet below the horizon. And the lighthouse steeple of St. Botolph’s Parish Church in Boston is 290 feet tall and visible from over 40 miles away, where it should be hidden a full 800 feet below the horizon!

“The distance across St. George's Channel, between Holyhead and Kingstown Harbour, near Dublin, is at least 60 statute miles. It is not an uncommon thing for passengers to notice, when in, and for a considerable distance beyond the centre of the Channel, the Light on Holyhead Pier, and the Poolbeg Light in Dublin Bay. The Lighthouse on Holyhead Pier shows a red light at an elevation of 44 feet above high water; and the Poolbeg Lighthouse exhibits two bright lights at an altitude of 68 feet; so that a vessel in the middle of the Channel would be 30 miles from each light; and allowing the observer to be on deck, and 24 feet above the water, the horizon on a globe would be 6 miles away. Deducting 6 miles from 30, the distance from the horizon to Holyhead, on the one hand, and to Dublin Bay on the other, would be 24 miles. The square of 24, multiplied by 8 inches, shows a declination of 384 feet. The altitude of the lights in Poolbeg Lighthouse is 68 feet; and of the red light on Holyhead Pier, 44 feet. Hence, if the earth were a globe, the former would always be 316 feet and the latter 340 feet below the horizon!”'—Zetetic Astronomy, Earth Not a Globe!” (59)

“The lights which are exhibited in lighthouses are seen by navigators at distances at which, according to the scale of the supposed ‘curvature’ given by astronomers, they ought to be many hundreds of feet, in some cases, down below the line of sight! For instance: the light at Cape Hatteras is seen at such a distance (40 miles) that, according to theory, it ought to be nine-hundred feet higher above the level of the sea than it absolutely is, in order to be visible! This is a conclusive proof that there is no ‘curvature,’ on the surface of the sea - ‘the level of the sea,’- ridiculous though it is to be under the necessity of proving it at all: but it is, nevertheless, a conclusive proof that the Earth is not a globe.”—William Carpenter, “100 Proofs the Earth is Not a Globe” (5)

The Isle of Wight lighthouse in England is 180 feet high and can be seen up to 42 miles away, a distance at which modern astronomers say the light should fall 996 feet below line of sight. The Cape L’Agulhas lighthouse in South Africa is 33 feet high, 238 feet above sea level, and can be seen for over 50 miles. If the world was a globe, this light would fall 1,400 feet below an observer’s line of sight! The Statue of Liberty in New York stands 326 feet above sea level and on a clear day can be seen as far as 60 miles away. If the Earth was a globe, that would put Lady Liberty at an impossible 2,074 feet below the horizon! The lighthouse at Port Said, Egypt, at an elevation of only 60 feet has been seen an astonishing 58 miles away, where, according to modern astronomy it should be 2,182 feet below the line of sight!

"The distance at which lights can be seen at sea entirely disposes of the idea that we are living on a huge ball.” —Thomas Winship, “Zetetic Cosmogeny” (58)

---

He is teaching people who will 'test it in real life' in circumstances that will hopefully save their life!

If so, then as marine layer visibility can vary, better to assume short than long.

[edby]

Rowbotham and Co. took their information from credible sources of the day. Dubey writes about the matter:

This http://200proofsthatericdubayisaliar.blogspot.com/2018/06/dubays-lighthouse-proofs-shown-to-be.html argues that Dubay's arguments are bogus.

Dubay took his sources from Rowbotham and Carpenter. Where is the independent credible evidence?

Please supply the 'credible sources for the day' that you are claiming.

[Tom Bishop]

Neither Dubey, Rowbotham, Winship, or Carpenter wrote the Lighthouses of the World book.

These are not their claims at all. Look up what quotes and citations are. These are the claims of academia and the traditional sciences.

From your link: "In the two Sailing Direction documents that I have access to online there is NOT A SINGLE ACCOUNT of a lighthouse or light that is visible from further than it should be on a spherical Earth."

Considering your video on how some of these ranges are determined, apparently by a theoretical Round Earth model on paper, we know why that may be the case. Your video appears to discredit this source.

[edby]

Now this is very interesting. Findlay’s 1861 book is here.

We can look up the claims above in this book, where Findlay gives both the height of the lighthouse and the figure ‘visible in miles’, which he gives as the minimum distance to which the light can be seen, in clear weather, from a height of 10 feet above sea level. Note he adds that ‘they could be seen at any distance with increased elevation’.

I checked out some of these using the curve calculator. Put in first the height of the lighthouse to give its distance to the horizon, then add the distance to the horizon of 10 feet.

It turns out (1) for the figures I looked at, Rowbotham adds about 5 miles to the ‘visible distance’, plus (2) he also cherry picks for the distances where Findlay’s estimate is inconsistent with his other estimates. For example, Rowbotham says “The Light at Madras, on the Esplanade, is 132 feet high and visible from 28 miles away”. But the figure Findlay gives is 24 miles, not 28! The curve calculator gives around 18 miles. However, on the same page Findlay says the lighthouse at Pondicherry is 131 feet, only a foot less than Madras, with a visible distance of 15 miles, which is less than expected.

So is someone making these numbers up?

[Tom Bishop]

Firstly, I believe the author you are quoting for those is Dubey, not Rowbotham. Rowbotham's quote is separated with quotes, with an emdash which says that it is from ENAG.

Secondly, 28 statute miles = 24.33 nautical miles. To defend Dubey, you are likely looking at conversions.

[stack]

Interesting information from Bob Schadewald’s book regarding Rowbotham’s lighthouse theories and how they may not be as accurate as claimed:

 "A substantial section of Earth Not a Globe is devoted to lighthouses that can be seen at greater distances than should be allowed by the earth’s rotundity.  Rowbotham drew most of his examples from Lighthouses of the World by Alexander Findlay, and Bresher examined this work closely.  He wrote:

“Parallax” gives about twenty cases of this kind, collected from a book, “Lighthouses of the World,” which contains a list of upwards of 2000 lighthouses, and then says (page 173,) “Many other cases could be given from the same work, shewing that the practical observations of mariners, engineers, and surveyors, entirely ignore the doctrine that the earth is a globe.” [ref. 1.79]

Bresher called this a bold but unwarranted assertion.  He had himself examined Findlay’s book and found therein entries for about 2000 lighthouses.  As far as he could tell, Rowbotham had found and listed almost every one that seemed to be visible at too great a distance.  But there was more:

Now while “Parallax” was attentively scanning the “Lighthouses of the World,” to find out some that could be seen farther than they ought to be seen, on the supposition that the earth is a globe of about 25,000 miles in circumference; he could not but find many more which cannot be seen as far as they ought to be, on the above assumption. [ref. 1.80]

Somehow Rowbotham neglected to mention these.  Bresher promised that “for every instance ‘Parallax’ can quote, where the distance given is greater than the theory requires, I will quote another where it is less.” [ref. 1.81]  As a down payment he listed ten lighthouses that (from the information provided) couldn’t be seen far as they should. [ref. 1.82]  Bresher suspected that misprints or local peculiarities accounted for many of the apparent discrepancies.  Besides, Findlay wrote that the lights used were typically powerful enough to be seen for 60 miles or more, and refraction sometimes made lighthouses visible farther than they should be.  In any case, Bresher argued that a few aberrant examples (about one percent) do not negate the earth’s sphericity.

In one case, Rowbotham used erroneous data published in a popular weekly, the Illustrated London News, which gave the wrong elevation for the light, when he could have found the correct figures in his favorite reference. [ref. 1.83]  Reverend Bresher discussed this in detail and wrote:

The above, I am sorry to say, is but a fair specimen of the manner in which “Parallax” conducts his “search after truth;” and I do not think it will commend itself to any right-minded man.  Anything he hears or reads, which can, by any means, be twisted into an argument against the Newtonian system, he seizes with avidity; not caring to ascertain its truth or untruth, even when he has the means of doing so, at hand. [ref. 1.84] "

[Tom Bishop]

Somehow Rowbotham neglected to mention these.  Bresher promised that “for every instance ‘Parallax’ can quote, where the distance given is greater than the theory requires, I will quote another where it is less.”

Come on, this is supposed to be meaningful? We can't see 30 miles into the horizon on every day and hour of the year.

A terrible argument, in my opinion. That person is clearly desperate for arguments and will say anything to try and deny whatever they want to deny. If the earth is a globe and if light travels in straight lines they should all be within globe distances, not some.

[stack]

Somehow Rowbotham neglected to mention these.  Bresher promised that “for every instance ‘Parallax’ can quote, where the distance given is greater than the theory requires, I will quote another where it is less.”

Come on, this is supposed to be meaningful? We can't see 30 miles into the horizon on every day and hour of the year.

A terrible argument, in my opinion. That person is clearly desperate for arguments and will obviously say anything to try and deny whatever they want to deny. If the earth is a globe and if light travels in straight lines they should all be within globe distances, not some.

In ENAG, the basis of his calculations:

1) “...and allowing the observer to be on deck, and 24 feet above the water
2) "Allowing 16 feet for the altitude of the observer (which is more than is considered necessary, 2 10 feet being the standard; but 6 feet may be added for the height of the eye above the deck)”

It looks like he uses #2 for all of the ones he lists in ENAG below:

"The Egerö Light, on west point of Island, south coast of Norway, is fitted up with the first order of the dioptric lights, is visible 28 statute miles, and the altitude above high water is 154 feet. On making the proper calculation it will be found that this light ought to be sunk below the horizon 230 feet.

The Dunkerque Light, on the south coast of France, is 194 feet high, and is visible 28 statute miles. The ordinary calculation shows that it ought to be 190 feet below the horizon.

The Cordonan Light, on the River Gironde, west coast of France, is visible 31 statute miles, and its altitude is 207 feet, which would give its depression below the horizon as nearly 280 feet.

The Light at Madras, on the Esplanade, is 132 feet high, and is visible 28 statute miles, at which distance it ought to be beneath the horizon more than 250 feet.

The Port Nicholson Light, in New Zealand (erected in 1859), is visible 35 statute miles, the altitude being 420 feet above high water. If the water is convex it ought to be 220 feet below the horizon.

The Light on Cape Bonavista, Newfoundland, is 150 feet above high water, and is visible 35 statute miles. These figures will give, on calculating for the earth's rotundity, 491 feet as the distance it should be sunk below the sea horizon."

In “Lighthouses of the World”, Rowbotham’s reference, the following stats are listed:

Egerö Light
Height above High Water: 154’
Visible in Miles: 24 miles

Dunkerque Light:
Height above High Water: 194’
Visible in Miles: 24 miles
(Rowbotham has it at 28 miles)

Cordonan Light
(Couldn’t find)

Light at Madras
Height above High Water: 132’
Visible in Miles: 24 miles
(Rowbotham has it at 28 miles)

Port Nicholson Light
Height above High Water: 450'
Visible in Miles: 30 miles
(Rowbotham has it 420’ & 35 miles)

Cape Bonavista Light
Height above High Water: 150'
Visible in Miles: 30 miles
(Rowbotham has it at 35 miles)

I’m not sure why Rowbotham has different numbers than what’s in his source. I couldn't find a mention of nautical miles in the book so perhaps he assumed they were nautical and converted to  statute.

Source:



And we are talking about observing the light of a lighthouse, not just an observation of the lighthouse itself.  Because there’s a distinct difference between observing a light source at distance versus, say just a structure/object.

Regarding Lighthouse lights:

"The luminous intensity of a light, or its candlepower, is expressed in international units called candelas. Intensities of lighthouse beams can vary from thousands to millions of candelas. The range at which a light can be seen depends upon atmospheric conditions and elevation. Since the geographic horizon is limited by the curvature of the Earth, it can be readily calculated for any elevation by standard geometric methods. In lighthouse work the observer is always assumed to be at a height of 15 feet, although on large ships he may be 40 feet above the sea. Assuming a light at a height of 100 feet, the range to an observer at 15 feet above the horizon will be about 16 nautical miles. This is known as the geographic range of the light. (One nautical mile, the distance on the Earth’s surface traversed by one minute of arc longitude or latitude, is equivalent to 1.15 statute miles or 1.85 kilometres.)

The luminous range of a light is the limiting range at which the light is visible under prevailing atmospheric conditions and disregarding limitations caused by its height and the Earth’s curvature. A very powerful light, low in position, can thus have a clear-weather luminous range greater than that when first seen by the mariner on the horizon. Powerful lights can usually be seen over the horizon because the light is scattered upward by particles of water vapour in the atmosphere; this phenomenon is known as the loom of the light.”

britannica.com/topic/lighthouse


This from the US Coast Guard’s Light List Volume I is the chart for distance to light source calculations which is different than Rowbotham's ENAG geometric observer to site calculations.

[edby]

See the chart below for some of the values given by Findlay, i.e. lighthouse height vs visibility in (statute) miles, against the theoretical GE values.

Note the majority of Findlay’s values are below the GE values, except for the four outliers which are the ones selected by Rowbotham.

Note also how closely the Findlay values follow the expected values. Why is this? Why is it difficult to find a Findlay lighthouse with a large height but low visibility, or with a low height but high visibilility? Why are short lighthouses never visible for a long distance?

Stepping right back, why did lighthouses exist at all in the days before satellites? Why go to the enormous expense of building them high at all?

If the earth is a globe and if light travels in straight lines they should all be within globe distances, not some.

If all the data is correct, yes. But the chart above statistically suggests high margin of error in Findlay's data. What credible sources assure you that these are not just errors?

Note that I had to eliminate one obvious typo in Findlay's data. He clearly didn't check his published work too closely.

[Tom Bishop]

The word "statute" appears nowhere in that nautical work. See the Google Books search feature. I will suggest that you two redo your analysis and graphs again and refrain from deception.

[shootingstar]

This Samuel Rowbotham chap seems to have been quite a colourful character. Clearly someone of very individual mind who would probably regarded in a certain way if he were around today. Certainly if his thoughts and beliefs figure significantly in the way FET works today, much is explained by that alone.