[Tontogary]

Charlatan Rowbotham did not present accurate facts to back up his crackpot theories.

Take the explanation of his attempt to explain why a compass needle is horizontal on about the equator.

http://www.sacred-texts.com/earth/za/za35.htm#page_227

He proudly boasts that on a round earth there can no way be a compass needle aligned horizontal with the earths surface, if the surface were a globe.
He also says and does not argue that the angle of dip of the needle increases in the north lattitude as well as the south, and in fact uses that as an observation that is not denied.

Now on that page is a diagram where he asserts that if the earth were round, then the compass needle will point to north, along a straight line represented by C-N. And makes the jump to the conclusion that it proves that the earth cannot be round.

There is a major flaw with his argument.
The compass needle does not point to a pole directly, lies parallel to the lines of magnetic flux, or force

The lines of magnetic force are represented on the attached picture, but dont believe me, get a magnet and iron filings, and a piece of paper. Zero cost if you have them, and do the experiment yourself.

On the other attached picture is shown the earths round shape and the magnetic field.

Now take this quote from EnaG

“and that the two facts that the compass always points towards the pole and yet on the equator lies without dip, cannot possibly co-exist on a globe. They do co-exist in nature, and are well ascertained and easily proved to do so, therefore the earth cannot possibly be a globe. They can co-exist on a plane with a northern or central region: they do beyond doubt co-exist, therefore, beyond doubt the earth is a plane.”

Taking his first statement, that a compass needle points towards the pole, is correct in a way, but the compass needle lies parallel to the lines of force, so will point north along the lines of longitude, (more or less) but the horizontal angle will be parallel to the lines of flux, and it is seen at the equator will be Horizontal, and dip increases in the north and south latitudes, which Charlatan Rowbotham says are “well ascertained and easily proved to do so” then this actually proves the earth is a globe, and debunks his theory.

This is a classic example of him getting a basic principle wrong, then using it to “prove” his theory, when in fact using the correct principle completely debunks his ideas.

The observation that the needle dips in the north and south equator is accepted and stated as a truth by him, but when you see the lines of force with the round earth placed on it, it is very evident that it does. More interestingly superimpose those lines of force on a plane surface and you cannot ever get the needle to do what it does, and that in fact disproves the flat earth theory!

So having debunked his methods on the first attempt, i can do so on most of his other flawed experiments.

[TomInAustin]

Charlatan Rowbotham did not present accurate facts to back up his crackpot theories.

Take the explanation of his attempt to explain why a compass needle is horizontal on about the equator.

http://www.sacred-texts.com/earth/za/za35.htm#page_227

He proudly boasts that on a round earth there can no way be a compass needle aligned horizontal with the earths surface, if the surface were a globe.
He also says and does not argue that the angle of dip of the needle increases in the north lattitude as well as the south, and in fact uses that as an observation that is not denied.

Now on that page is a diagram where he asserts that if the earth were round, then the compass needle will point to north, along a straight line represented by C-N. And makes the jump to the conclusion that it proves that the earth cannot be round.

There is a major flaw with his argument.
The compass needle does not point to a pole directly, lies parallel to the lines of magnetic flux, or force

The lines of magnetic force are represented on the attached picture, but dont believe me, get a magnet and iron filings, and a piece of paper. Zero cost if you have them, and do the experiment yourself.

On the other attached picture is shown the earths round shape and the magnetic field.

Now take this quote from EnaG

“and that the two facts that the compass always points towards the pole and yet on the equator lies without dip, cannot possibly co-exist on a globe. They do co-exist in nature, and are well ascertained and easily proved to do so, therefore the earth cannot possibly be a globe. They can co-exist on a plane with a northern or central region: they do beyond doubt co-exist, therefore, beyond doubt the earth is a plane.”

Taking his first statement, that a compass needle points towards the pole, is correct in a way, but the compass needle lies parallel to the lines of force, so will point north along the lines of longitude, (more or less) but the horizontal angle will be parallel to the lines of flux, and it is seen at the equator will be Horizontal, and dip increases in the north and south latitudes, which Charlatan Rowbotham says are “well ascertained and easily proved to do so” then this actually proves the earth is a globe, and debunks his theory.

This is a classic example of him getting a basic principle wrong, then using it to “prove” his theory, when in fact using the correct principle completely debunks his ideas.

The observation that the needle dips in the north and south equator is accepted and stated as a truth by him, but when you see the lines of force with the round earth placed on it, it is very evident that it does. More interestingly superimpose those lines of force on a plane surface and you cannot ever get the needle to do what it does, and that in fact disproves the flat earth theory!

So having debunked his methods on the first attempt, i can do so on most of his other flawed experiments.

Yes, he did a lot of that.   He would quote himself as proof.   He would be laughed off the stage at any university in the world today.

[Tom Bishop]

Actually, Rowbotham is very exact in his wordings:

From ENAG:

If any small object to represent a ship is placed on the equator of an artificial globe and kept at right angles to the meridian lines, it will at once be seen that it cannot be otherwise than as above stated; and that the two facts that the compass always points towards the pole and yet on the equator lies without dip, cannot possibly co-exist on a globe.

He is correct. Those facts cannot coexist on a globe. That is why, in RET, they had to change the theory to declare that the compass did not point at the pole.

[Stagiri]

Actually, Rowbotham is very exact in his wordings:

From ENAG:

If any small object to represent a ship is placed on the equator of an artificial globe and kept at right angles to the meridian lines, it will at once be seen that it cannot be otherwise than as above stated; and that the two facts that the compass always points towards the pole and yet on the equator lies without dip, cannot possibly co-exist on a globe.

He is correct. Those facts cannot coexist on a globe. That is why they had to change the theory to declare that the compass did not point at the pole in RET.

(Magnetic) Compasses do not simply "point towards the pole", they align themselves with the horizontal component of the Earth's magnetic field.

[Tom Bishop]

(Magnetic) Compasses do not simply "point towards the pole", they align themselves with the horizontal component of the Earth's magnetic field.

And how did they know how to design to magnetic field before the dip reading studies?

Rowbotham is pointing out evidence against the notion that the compass points at the poles.

[Stagiri]

(Magnetic) Compasses do not simply "point towards the pole", they align themselves with the horizontal component of the Earth's magnetic field.

And how did they know how to design to magnetic field before the dip reading studies?

Rowbotham is pointing out evidence against the notion that the compass points at the poles.

Nobody designed the magnetic field, it is an observable natural phenomenon.

[Parallax]

Oh look, tontogary badmouthing Dr Rowbotham yet again. Anyone would think he's got nothing else to do with his time...

Anyway, how is this 'proof'? It's not. A compass points north and all I've seen from you is speculation. The top scientific boffins of the day couldn't disprove Dr Rowbotham, yet you apparently can now. Hmmm. Tom has already posted a quote that proves Dr Rowbotham correct.

[stanlee]

these people choose to take 'it points to the pole' quite literally. it suits them.

[xenotolerance]

That is why, in RET, they had to change the theory to declare that the compass did not point at the pole.

This is wrong. Knowledge of magnetic field lines predates Rowbotham.

[Tom Bishop]

That is why, in RET, they had to change the theory to declare that the compass did not point at the pole.

This is wrong. Knowledge of magnetic field lines predates Rowbotham.

It was known that the earth was magnetic in some form, but the properties of the magnetic field were not mapped until the mid 1800's.

http://www.madsci.org/posts/archives/2007-05/1178030012.Sh.r.html

German scientist Carl Gauss is usually credited with being the first to make detailed observations of the field's direction and strength around 1840.

https://www-spof.gsfc.nasa.gov/Education/gauss.htm

The greatest help however came from the British empire, whose "Magnetic Crusade" led by Sir Edward Sabine set up stations from Canada to Tasmania (then known as "Van Diemen's Land"). The vast network not only made possible the first global models of the field, but also demonstrated the world-wide character of magnetic storms.

[HorstFue]

(Magnetic) Compasses do not simply "point towards the pole", they align themselves with the horizontal component of the Earth's magnetic field.

That's correct. magnetic compasses only use the horizontal component of the magnetic field. The vertical component is overcompensated by weight and the mount/suspension point. The mount point is above the center of weight of the compass needle.
Did you ever closely examine a simple compass? The "needle" has a small dome in the middle, so that the suspension point is above the needle, higher than the center of mass of the needle.
Other compasses, e.g. used on ships, have a cardan suspension, also compensated by weight, so that the compass rose (a disk instead o a simple needle) always stays horizontal.

[6or1/2Dozen]

Compasses are counter-weighted to compensate for the inclination of Earth's magnetic field.

via Wikipedia:
https://en.wikipedia.org/wiki/Compass

and Suunto (a compass manufacturer)
http://www.suunto.com/en-US/Support/Compasses-feature-index/Understanding-balancing-zones/

The pivot point can be set above the needle's center of gravity and weights can be added to compensate. High precision compasses are built to compensate based on the area they will be used in.

The magnetic needle itself even has some built-in compensation itself. Monopole magnets aren't really a very common thing and don't even exist naturally. The needle in the compass has a N and S end. The force trying to dip the end pointing toward the Northern is counteracted by the fact that the other end is trying to dip to toward the South in the opposite direction.

Also, there's this thing called a 'Dip circle' (aka 'Dip needle') invented in 1581. Dip circles (also dip needles) are used to measure the angle between the horizon and the Earth's magnetic field (the dip angle). They were used in surveying, mining and prospecting as well as for the demonstration and study of magnetism.

It was invented because some dude actually noticed the needle on a compass dipped in 1544.

Reference:
https://en.wikipedia.org/wiki/Dip_circle

So, pretty much, yeah, that needle dipping thing sort of actually happens. A tool was made to take advantage of it and compasses were being designed to compensate for it (possibly since 1544) .

[Tom Bishop]

The dip compass was invented in centuries prior, but the magnetic field was not mapped on a wide scale until the mid 1800's around the time of Earth Not a Globe.

[xenotolerance]

one might notice that the year 1840 is before the year 1849. so, no

also, did the original 16 pages even talk about compasses

[Tontogary]

Actually, Rowbotham is very exact in his wordings:

From ENAG:

If any small object to represent a ship is placed on the equator of an artificial globe and kept at right angles to the meridian lines, it will at once be seen that it cannot be otherwise than as above stated; and that the two facts that the compass always points towards the pole and yet on the equator lies without dip, cannot possibly co-exist on a globe.

He is correct. Those facts cannot coexist on a globe. That is why, in RET, they had to change the theory to declare that the compass did not point at the pole.

Oh dear Tom, how incredibley selective of you. I show you why the compass will be without dip at the equator, and you then just repeat Charlatan Rowbothams (obviously flawed statement) and say it is good! The first claim, that the needle always points to the pole is more or less correct in the horizontal plane, but clearly untrue in the vertical. And as for the second that there cannot be zero dip at the equator is simply shown in elementary grade science experiments, of which you seem to claim are false, made up etc!

Both conditions do exist on a globe.

Please can you explain how magnetism theory was after changed after EnaG? It is a positive claim and therefore the burden of proof lies with you!

However if you wish to debate the the point please show me the magnetic flux lines drawn on a plane earth, and show how the rate of dip increases with lattitude, a point EnaG uses as a fact and undeniable, and how it is 0 at the equator?

Given that you cannot show any sort of theory on it (Charlatan Rowbotham couldn’t either) it is assumed. Therefore your statement fails under Occams Razor.

A simple experiment, free of charge will demonstrate what i say.
Place a bar magnet next to a compass, in the mid point between the poles, and an inch or so away from the compass with the bar magnet being longer than the compass. The compass can even be a tiny little button compass, in fact this would represent the experiment even better.

Note the direction of the needle is not directly at the pole. Empirical proof!

[Tontogary]

Oh look, tontogary badmouthing Dr Rowbotham yet again. Anyone would think he's got nothing else to do with his time...

Anyway, how is this 'proof'? It's not. A compass points north and all I've seen from you is speculation. The top scientific boffins of the day couldn't disprove Dr Rowbotham, yet you apparently can now. Hmmm. Tom has already posted a quote that proves Dr Rowbotham correct.

Examining the Charlatans flawed statements and providing experiments and actual physics of why they are false is called badmouthing is it?

You should listen to your mentors words, and not be so hypocritical!

“The true business of a critic is to compare what he reads with known and provable data, to treat impartially the evidence he observes, and point out logical deficiencies and inconsistencies with first principles, but never to obtrude his own opinions. He should, in fact, at all times take the place of Astrea, the Goddess of Justice, and firmly hold the scales, in which the evidence is fairly weighed.

I advise all my readers who have become Zetetic not to be content with anything less than this; and also not to look with disfavour upon the objections of their opponents. Should such objections be well or even plausibly founded, they will only tend to free us from error, and to purify and exalt our Zetetic philosophy.”

You should in fact be thanking me for helping your “Zetetic philosophy” understand the real world!

[Tontogary]

(Magnetic) Compasses do not simply "point towards the pole", they align themselves with the horizontal component of the Earth's magnetic field.

And how did they know how to design to magnetic field before the dip reading studies?

Rowbotham is pointing out evidence against the notion that the compass points at the poles.

Magnetic dip was discovered in the mid 14th century, and measured in the late 14th century, way before EnaG was written. It was studied way way before he was born.

The Charlatan himself quoted

“For instance, it is known that the "dipping needle" is horizontal or without "dip" at the equator; and that the "dip" increases on sailing north and south: and is greatest at the magnetic centre.” So you surely have to agree with that?

So let me help with showing a picture of an experiment, and guess what? At the place where the equator will be on a RE, the needle points parallel to the surface, and then gets steeper until it is att maximum at the pole (or magnetic Center) shal i try to superimpose the world onto that picture below for those of you who have problems following simple diagrams, and making the connection betweeen the two?

I am sure Tom or Parallax will say the picture is photoshopped, but it is so very very easy to verify, (empirically) that the needle does NOT point directly to the pole, contrary to Toms assertion that it does.

Tom must be a reincarnation of the Charlatan,   “Rowbotham is pointing out evidence against the notion that the compass points at the poles.” Contradicting himself, as i cannot see where the Charlatan argues against the needle pointing directly to north, but also used the fact that it does point directly to north in a diagram used to disprove the round earth!

[Tom Bishop]

Not all magnets make that shape. A magnet with a North and South pole closer together would make a more circular and radial magnetic field. It was also unknown if there was more than one magnetic element in the earth -- if we introduce the concept of multiple magnets, a whole variety of shapes could be made.

Before the mid 1800's it was known that the earth was magnetic in some form, but the exact layout of the fields was unknown. Your accusation that Rowtham did not know about the layout of the earth's magnetic field is misplaced, since it was just then being studied on a large scale at that time.

Rowbotham's conclusions based on the premises provided are accurate. If a premise is wrong, it means that some Round Earth academic was wrong, since that is where they are taken from.

[6or1/2Dozen]

Not all magnets make that shape. A magnet with a North and South pole closer together would make a more circular and radial magnetic field. It was also unknown if there was more than one magnetic element in the earth -- if we introduce the concept of multiple magnets, a whole variety of shapes could be made.

Before the mid 1800's it was known that the earth was magnetic in some form, but the exact layout of the fields was unknown. Your accusation that Rowtham did not know about the layout of the earth's magnetic field is misplaced, since it was just then being studied on a large scale at that time.

Rowbotham's conclusions based on the premises provided are accurate. If a premise is wrong, it means that some Round Earth academic was wrong, since that is where they are taken from.

I hate to use your own link against you. (I'm lying, I actually love it.)

Referencing:
http://www.madsci.org/posts/archives/2007-05/1178030012.Sh.r.html
(That's a link you provided earlier)

English scientist William Gilbert pioneered research into magnetism and electrical attractions. In 'De Magnete' (1600), he was the first to describe the earth's magnetic field and to postulate the relationship between electricity and magnetism. (He introduced the term 'electricity'). He corrected described the Earth as being like a giant bar magnet." [emphasis added]

Carl Gauss is usually credited with being the first to make detailed observations of the field's direction and strength around 1840. Let me re-emphasis both direction and strength. Others observed direction prior to Gauss, other observed strength prior to Gauss. Gauss applied his mathematical genius and created model from the measurements of both direction and strength.

Tom's statement suggesting that the Earth's magnetic field was just being studied on a large scale only beginning around the  mid 1800's seems patently false.

Declination and inclination were discovered prior to 1544. It seems that [in Europe] the Earth's magnetic field was correctly being described as a bar magnet since 1600. It seems that the general layout was understood to be a dipole bar magnet slightly inclined to the axis of rotation in 1600. It was only the intensity that was not first measured in 1791, and modeled (detailed) for both direction and strength around 1840.

You know what, just read the article yourself...
https://en.wikipedia.org/wiki/History_of_geomagnetism

I don't know what premises Rowbotham based his premises on, it certainly doesn't appear to be the what was actually know about magnetism at the time. Best I can tell his premises are based on ignorance (stated without accusation of intent). Dip needles had bee around for a while, their operation should have been decently understood after 300 years (or so) of use, being they point 90 degrees down at the North pole and (presumably) they would point 90 up at the south. That means in the middle (at the equator) they'd read, what? 0 - aka horizontal, meaning there sum total magnetic inclination at that latitude is 0, meaning the needle on a compass should not dip, irrespective to the shape of the Earth's surface.

Why does it seem like he didn't know about this?

[HorstFue]

I see two observations/claims Rowbotham in this chapter:

• Compass needle always directly points to the mag. North Pole. So - sweeping magnetic field lines under the carpet - a compass at the equator would be pointing straight through the globe to the mag. North Pole, showing a "dip" of about 45°.
• He does not deny the "dip", he even affirms it: For instance, it is known that the "dipping needle" is horizontal or without "dip" at the equator; and that the "dip" increases on sailing north and south: and is greatest at the magnetic centre.

Now let's apply this to the flat earth model:
As the compass needle points directly at the north pole and there's a significant "dip" already for places far away from the geographic North pole, so where's the magn. North Pole? The compass needle is pointing downwards directly to the magn. North Pole! You could even do some triangulation, which would find the magn. North Pole way, way down below the surface.
But now, what's the "dip" at the equator? Sorry, now also with this model the compass needle could no more be horizontal.
Let's say with Rowbotham's words: "... and that the two facts that the compass always points towards the pole and yet on the equator lies without dip, cannot possibly co-exist on a globe plane."