82. The Port Nicholson Light at a height of 420 feet should not be visible from a ship 35 miles away on a spherical Earth
“The Port Nicholson Light in New Zealand is 420 feet above sea-level and visible from 35 miles away where it should be 220 feet below the horizon.”
Probably a bogus observation, but in any case Dubay and Samuel Rowbotham can't do trigonometry.
For evidence that the quoted observation is bogus, click here:
Why Dubay's lighthouse quotes are bogus
However, if you want to take the observation as genuine read on to see why this still does not add up to a proof.
Dubay again uses the incorrect calculation to determine how high the observer needs to be to see the light.
Using the correct calculation, the observer on the ship would have to be at a height of 65 feet.
From the deck of a ship that would mean that the observer would be about 50 feet too low to see the lighthouse.
However, as with so many of Dubays "proofs" this is taken from Samuel Rowbotham's "Zetetic Astronomy: Earth Not a Globe" published in 1881.
The relevant paragraphs from the book are:
Now the observation can make sense on spherical Earth. In 1881 the ships that would be observing the lighthouse would be sailing ships or steam ships that still had sails as a back-up. Look-outs on those ships would be placed in a crows nest near the top of the main mast.
So in summary, Samuel Rowbotham may have quoted an accurate account of how far out to sea the lighthouse could be seen, but he was still as ignorant of trigonometry as Dubay. He performed the incorrect calculation and used this to incorrectly conclude that the Earth could not be a sphere. Although it would have made no difference to his conclusion, he also makes the mistake of assuming that the ships lookout would be standing on the deck when the best vantage point on a sailing ship is from the top of the main mast / crows nest.
Also note how similar this is to the height required in the example given in proof 81 (79 feet). This supports the contention that the distances mentioned in these quotes were based on the assumption that the lookout was located near the top of the main mast.
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Probably a bogus observation, but in any case Dubay and Samuel Rowbotham can't do trigonometry.
For evidence that the quoted observation is bogus, click here:
Why Dubay's lighthouse quotes are bogus
However, if you want to take the observation as genuine read on to see why this still does not add up to a proof.
Dubay again uses the incorrect calculation to determine how high the observer needs to be to see the light.
Using the correct calculation, the observer on the ship would have to be at a height of 65 feet.
From the deck of a ship that would mean that the observer would be about 50 feet too low to see the lighthouse.
However, as with so many of Dubays "proofs" this is taken from Samuel Rowbotham's "Zetetic Astronomy: Earth Not a Globe" published in 1881.
"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. The following are examples:-
....
Allowing 16 feet for the altitude of the observer .....
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."
Now the observation can make sense on spherical Earth. In 1881 the ships that would be observing the lighthouse would be sailing ships or steam ships that still had sails as a back-up. Look-outs on those ships would be placed in a crows nest near the top of the main mast.
"... masts were still to be found on many merchant and passenger ships well into the 1900s"
Source: https://www.uh.edu/engines/epi1338.htmThe 65 feet of elevation required to see the Port Nicholson Light on a spherical Earth is absolutely consistent with the elevation we could expect for look outs stationed on the main mast.
So in summary, Samuel Rowbotham may have quoted an accurate account of how far out to sea the lighthouse could be seen, but he was still as ignorant of trigonometry as Dubay. He performed the incorrect calculation and used this to incorrectly conclude that the Earth could not be a sphere. Although it would have made no difference to his conclusion, he also makes the mistake of assuming that the ships lookout would be standing on the deck when the best vantage point on a sailing ship is from the top of the main mast / crows nest.Also note how similar this is to the height required in the example given in proof 81 (79 feet). This supports the contention that the distances mentioned in these quotes were based on the assumption that the lookout was located near the top of the main mast.
< Prev 81-90 Next >
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