Magnetic weapons

Jens Nordlunde · 12th February 2005, 09:48 PM

The trick with the number seems as it if was a good idea – and I am very pleased J.

Thank you for your answers so far – and thank you very much for keeping so close to the topicJ

Gene you must have been watching when I put the thread on, as you were very fast, and the story you tell is just what it is all about – thank you.

Fearn, what you write sounds interesting, but is it something that you know, or something that you think? Thank you Gene good point!

Nechesh – I can’t say that I agree with you about magnetising blade anew, on the other hand, I think it must be up to the owner of the blade.

Rivkin, thank you for your input. What you write is important, and I do very much agree with you that the cooling of a sword means a lot to how the magnetism is preserved. I do however have some problems with what you write when you write: Such swords rather then becoming demagnetized with time would first actually become uniformly magnetized, and then would assume some magnetization due to the current earth's magnetic field (if it lies in the same place all the time), however it's even a big question if this _ever_ happens (it well may be that the current magnetized state is so efficient that it should take unphysical long time to change it using weak fields and temperatures.
Somewhere I read that the magnetism of the Earth was so weak that it would make little or no influence on a sword, although it was lying for a long time in the same place.

Do you have any comments to this. If you do, please come with themJ.

Yannis. 1. Your percentage is bigger than mine, although I have not tried all mine blade as yet.
2, 3-4 Same here.
5. Funny I have the same feeling – I wonder why?
6. Can’t beat that – if the needle circles like a maniac, it must be wild, the magnetism must be really strong. Do you know how old the kard and the kinjal are?

Gene we will look forward to the pictures of the magnet felt.

Thank you very much so far

Jens

fearn · 12th February 2005, 11:29 PM

Hi Jens,

That's something I think. I'm having fun contemplating magnetism in blades for a couple of reasons:

1. It exists.

2. It exists in folded blades,

3. It exists in tempered blades.

1. is self-evident (and I'm enjoying reading these accounts). As for 2., well, if a sheet of magnetized steel is folded over itself, doesn't it cancel out? What about if it's folded over itself a bunch of times? 3., What happens to magnetization when a blade is differentially heat treated? Since the crystal structure is getting deformed, I'm still puzzling out whether this would affect a magnetic field. Basically, I don't see a straight route from magnetite to a blade without remagnetizing the blade after it's manufactured.

Balanced against all this skepticism are the observations people are reporting here. Perhaps there's a way for a hunk of magnetite to retain its magnetism after it's been folded, tempered, heat treated (and possibly alloyed). Personally, I think the magnetic field came later. As Nechesh points out, it's quite easy to do. As to where those asymmetric fields up and down blades came from, I think that an experiment with some magnets and a non-magnetized sword are in order

Fearn (not Fern, thanks!)

Rivkin · 13th February 2005, 12:13 AM

Quote:

Originally Posted by Jens Nordlunde

Somewhere I read that the magnetism of the Earth was so weak that it would make little or no influence on a sword, although it was lying for a long time in the same place.

Do you have any comments to this. If you do, please come with themJ.
Jens

That's why I wrote "however it's even a big question if this _ever_ happens". In general I would say that magnetic field of the earth is strong enough to magnetize all the ancient pottery. It's way more tricky with swords and big iron objects in general. I'm pretty sure that in a cool place 5000-10000 years of lying in the same place will certainly make a difference, and may be it will make a lot of difference if the sword is heated up and sloooowly cooled down.

In short there are so many parameters (defects in the crystalline structure, historical facts like being made in the place with iron deposits, macroscopic shape etc.) that can affect any sword's magnetization that it's impossible to guess "why ?".

Robert · 13th February 2005, 01:26 AM

This is something that I learned along time ago. Take an iron bar and point it so one end is pointing north and the other is pointing south (using a compass) and strike the south pointing end with a hammer. The bar will magnetize. Maybe someone has tried this with swords?

Jim McDougall · 13th February 2005, 06:04 AM

Although I cannot claim any aptitude toward physics, I cannot resist being 'drawn'

to this fascinating thread!! As always, Jens poses intriguing questions on most unusual topics.

The subject of metallurgy as applied in the blades of edged weapons has often been discussed here, as has the more esoteric aspect of the use of meteoric iron, but little concerning magnetic properties in blades has been considered. The exception, as has been noted by Nechesh, was his post of several years ago and is linked in his previous post.

The presence of lodestones, or magnetite with the iron attracting properties discussed, has been known since early Greek times. Other than being considered an interesting anomaly, it does not seem that this curious material keyed any special purpose. One of the primary features of magnetism has been its use in navigation and the development of the compass, but this apparantly did not occur until about the end of the 11th century AD in China.
There are no references in old Greek and Roman literature about the directive properties of magnetic material (the term magnet came from the Greek term for people called the Magnetes who lived in Magnesia,in Thessaly).
The first use of crude compasses at sea is reported by the Chinese, and believed to refer to those used by Muslim traders in regions between Canton and Sumatra in latter 11th c.
There was little attention given to magnetic navigation in the west until the latter 16th century with most attention applied to celestial navigation, aside from isolated interest.

Since lodestone, or magnetite was so little known through these periods of history, and certain ferromagnetic metals such as nickel and cobalt were not identified until the 18th and 19th centuries, it does not seem that there would have been any deliberate attention given to applying magnetic properties in forged steel in early times. It does seem however, that the occurence of such forces would have inspired mystical and occult attention, along with other natural phenomenon such as meteoric iron.

Although as I have noted, I cannot add much to the discussion on the physical properties of magnetism, I just wanted to share some observations that pertain to the historical perspective,

Best regards,
Jim

Yannis · 13th February 2005, 10:31 AM

Jim
There are 2 Magnesia in greek world. The one you mention is an area in central Greece that includes mount Pelion. It is there that in myths the wise Centauri lived. The second one is a city. Magnesia on the Meander (river) was in Ionia (Asia Minor). It was destroyed by Cimmerians and rebuild. Its most famous child was Pausanias the great geographer of the 2nd century A.D. Both places are claiming the origin of the term “magnetism”. Also there is a third story of a Cretan shepherd that found the phenomenon. His name was Magnes.

Jens
The kindjal is hallmarked late 19th century. I estimate the kard early 19th. This kard is a real magnet. It can easy hold a small nail or a safety pin. I examined the kard again. Nothing strange except some line marks on blade like old grinding. Can grinding magnetise a blade?

Jens Nordlunde · 13th February 2005, 10:47 AM

Hi all,

Not all magnetite can become lodestone, it takes a special crystal structure, see what Dr. Peter Wasilewski, of NASA's Goddard Space Flight Centre, writes here http://www.phy6.org/earthmag/lodeston.htm this will answer some of the questions asked.

Fearn, I am nor a specialist on this, but I would think, that if you fold a blade many times, it will loose magnetism. I agree with you, I also think the magnetism on blades was made later – but why?
If we believe in what Dr. Peter Wasilewski writes, the lightening together with a good portion of superstition would lead them to believe that the Gods had made this metal.
I don’t know if lodestone was ever used for weapons, maybe it was too difficult to get the iron out of the stone, or maybe the percentage of iron was too small, I don’t know – but one thing it could do, and that was making other iron weapons magnetic. If they believed that the Gods gave them this stone, they would also believe in, that using this stone to magnetize a blade would give the user more power.

Nechesh, I know you did not advocating for magnetizing blades. I clean my blade and etch them, but I don’t magnetise them. The reason for this is that I don’t know if the blade was magnetised from the start, that is why I leave it be.

Rivkin, it seems as if Dr. Peter Wasilewski does not agree with you about the magnetic felt of the earth when it comes to lodestone, maybe the magnetic felt could influence ancient pottery, I don’t know, and I don’t know the reason for this.
I think you are right, that if any magnetism would be recovered in a blade after heating, it must cooled very slowly – just like the Indians did with wootz.
The defects in crystalline structures, what other metal the iron was mixed with, even in very small doses must have been a problem for the smiths, as this would have affected the way the iron should be treated. It seems to me, that wootz from one ore might have needed a slightly different treatment than wootz from another ore, according to how the iron was mixed. But I never saw anywhere that the wootz ores were magnetic, only the lodestone.

Robert, on the first link I gave, it somewhere say, that if you take a big nail which is not magnetised and hammer on one end for 50 times, the nail is magnetic – if you turn the nail and do the same on the other en of the nail, you will change the poles.

Jim, I think a crude compass was made much earlier than about 11th century AD, try to read this:
For many years magnetism was just a curious natural phenomenon and its only use was in navigation as what we now refer to as the mariner's compass and which was probably first developed by the Chinese some 4500 years ago. The earliest mariner's compass comprised a splinter of loadstone carefully floated on the surface tension of water.
You can find the whole text here http://www.newi.ac.uk/BUCKLEYC/magnet.htm if you are surprised when reading this, I understand you – I was surprised too.

Does anyone know if lodestone alone, or in combination with iron/wootz was used for making weapon?

Interesting questions you ask – but you must remember that I am not an expert – I try to learn as fast as you ask the questions.

yannis, interesting what you write to Jim, try to have a look on the link I gave him.
Yes, filing on a blade can make it magnetic, but you would have to file in the same direction the whole time - not back and forth, and I think it would be an advantage if the file was magnetic. I doubt however if it would make a kard blade as magnetic as the one you have, but I don't know it.

Jens

Rivkin · 13th February 2005, 05:26 PM

I believe that the case with Wasilevski is that his message have been probably perverted by "popular" explanation - probably what he meant is that extremely well magnetized samples have origins different from just being cooled in Earth magnetic field.

Concerning the knowledge that ancient iron (whether in pottery, iron deposits or special spherical boxes lying on the ocean's floor) is magnetized alongside the Earth magnetic field at the time of the iron sample's cooling period is a well known fact, avoiding "real" papers I would bring your attention to:
http://www.sciencetech.technomuses.c...fo_Magnets.cfm

"Magnetite is magnetic because its molecular structure has allowed it to retain the alignment of particles caused by the Earth's magnetic field during its formation millions of years ago. When heated to high temperatures magnetite loses its natural magnetism. "
http://www.tufts.edu/as/wright_cente...xt_plan_5.html
"Finally, a fourth bit of evidence also favors the idea of plate tectonics, although here the data aren’t as robust, their implications not as clear. This evidence is supplied by paleomagnetism—the study of ancient magnetism. Everyday experience tells us that iron is magnetic; in fact, any metal containing even small amounts of iron ore is usually magnetized. However, when iron is heated to temperatures ~1000 K, it loses its magnetic properties as individual atoms jostle freely (which is why magnetic thermometers often fall off the side of a roaring wood stove). Hot basalt—the dark, dense stuff of volcanoes—impregnated with traces of iron and upwelling from cracks in the oceanic ridges, is thus not magnetic. As the basalt cools, magnetism sets in as each iron atom effectively responds to Earth’s magnetic field like a compass needle. When the basalt solidifies to form hard rock shortly thereafter, it fixes the orientation of the embedded iron, since the iron atoms align themselves with the orientation of Earth’s field at the time of cooling. Accordingly, the ocean-floor matter has preserved within it a history of Earth’s magnetism."

12th February 2005, 09:48 PM	#1
Jens Nordlunde Member Join Date: Dec 2004 Location: Europe Posts: 2,718	The trick with the number seems as it if was a good idea – and I am very pleased J. Thank you for your answers so far – and thank you very much for keeping so close to the topicJ Gene you must have been watching when I put the thread on, as you were very fast, and the story you tell is just what it is all about – thank you. Fearn, what you write sounds interesting, but is it something that you know, or something that you think? Thank you Gene good point! Nechesh – I can’t say that I agree with you about magnetising blade anew, on the other hand, I think it must be up to the owner of the blade. Rivkin, thank you for your input. What you write is important, and I do very much agree with you that the cooling of a sword means a lot to how the magnetism is preserved. I do however have some problems with what you write when you write: Such swords rather then becoming demagnetized with time would first actually become uniformly magnetized, and then would assume some magnetization due to the current earth's magnetic field (if it lies in the same place all the time), however it's even a big question if this _ever_ happens (it well may be that the current magnetized state is so efficient that it should take unphysical long time to change it using weak fields and temperatures. Somewhere I read that the magnetism of the Earth was so weak that it would make little or no influence on a sword, although it was lying for a long time in the same place. Do you have any comments to this. If you do, please come with themJ. Yannis. 1. Your percentage is bigger than mine, although I have not tried all mine blade as yet. 2, 3-4 Same here. 5. Funny I have the same feeling – I wonder why? 6. Can’t beat that – if the needle circles like a maniac, it must be wild, the magnetism must be really strong. Do you know how old the kard and the kinjal are? Gene we will look forward to the pictures of the magnet felt. Thank you very much so far Jens

12th February 2005, 11:29 PM	#2
fearn Member Join Date: Dec 2004 Posts: 1,247	Hi Jens, That's something I think. I'm having fun contemplating magnetism in blades for a couple of reasons: 1. It exists. 2. It exists in folded blades, 3. It exists in tempered blades. 1. is self-evident (and I'm enjoying reading these accounts). As for 2., well, if a sheet of magnetized steel is folded over itself, doesn't it cancel out? What about if it's folded over itself a bunch of times? 3., What happens to magnetization when a blade is differentially heat treated? Since the crystal structure is getting deformed, I'm still puzzling out whether this would affect a magnetic field. Basically, I don't see a straight route from magnetite to a blade without remagnetizing the blade after it's manufactured. Balanced against all this skepticism are the observations people are reporting here. Perhaps there's a way for a hunk of magnetite to retain its magnetism after it's been folded, tempered, heat treated (and possibly alloyed). Personally, I think the magnetic field came later. As Nechesh points out, it's quite easy to do. As to where those asymmetric fields up and down blades came from, I think that an experiment with some magnets and a non-magnetized sword are in order Fearn (not Fern, thanks!)

13th February 2005, 01:26 AM	#4
Robert EAAF Staff Join Date: Feb 2005 Location: Centerville, Kansas Posts: 2,196	This is something that I learned along time ago. Take an iron bar and point it so one end is pointing north and the other is pointing south (using a compass) and strike the south pointing end with a hammer. The bar will magnetize. Maybe someone has tried this with swords?

13th February 2005, 06:04 AM	#5
Jim McDougall Arms Historian Join Date: Dec 2004 Location: Route 66 Posts: 10,192	Although I cannot claim any aptitude toward physics, I cannot resist being 'drawn' to this fascinating thread!! As always, Jens poses intriguing questions on most unusual topics. The subject of metallurgy as applied in the blades of edged weapons has often been discussed here, as has the more esoteric aspect of the use of meteoric iron, but little concerning magnetic properties in blades has been considered. The exception, as has been noted by Nechesh, was his post of several years ago and is linked in his previous post. The presence of lodestones, or magnetite with the iron attracting properties discussed, has been known since early Greek times. Other than being considered an interesting anomaly, it does not seem that this curious material keyed any special purpose. One of the primary features of magnetism has been its use in navigation and the development of the compass, but this apparantly did not occur until about the end of the 11th century AD in China. There are no references in old Greek and Roman literature about the directive properties of magnetic material (the term magnet came from the Greek term for people called the Magnetes who lived in Magnesia,in Thessaly). The first use of crude compasses at sea is reported by the Chinese, and believed to refer to those used by Muslim traders in regions between Canton and Sumatra in latter 11th c. There was little attention given to magnetic navigation in the west until the latter 16th century with most attention applied to celestial navigation, aside from isolated interest. Since lodestone, or magnetite was so little known through these periods of history, and certain ferromagnetic metals such as nickel and cobalt were not identified until the 18th and 19th centuries, it does not seem that there would have been any deliberate attention given to applying magnetic properties in forged steel in early times. It does seem however, that the occurence of such forces would have inspired mystical and occult attention, along with other natural phenomenon such as meteoric iron. Although as I have noted, I cannot add much to the discussion on the physical properties of magnetism, I just wanted to share some observations that pertain to the historical perspective, Best regards, Jim

13th February 2005, 10:31 AM	#6
Yannis Member Join Date: Dec 2004 Location: Athens Greece Posts: 479	Jim There are 2 Magnesia in greek world. The one you mention is an area in central Greece that includes mount Pelion. It is there that in myths the wise Centauri lived. The second one is a city. Magnesia on the Meander (river) was in Ionia (Asia Minor). It was destroyed by Cimmerians and rebuild. Its most famous child was Pausanias the great geographer of the 2nd century A.D. Both places are claiming the origin of the term “magnetism”. Also there is a third story of a Cretan shepherd that found the phenomenon. His name was Magnes. Jens The kindjal is hallmarked late 19th century. I estimate the kard early 19th. This kard is a real magnet. It can easy hold a small nail or a safety pin. I examined the kard again. Nothing strange except some line marks on blade like old grinding. Can grinding magnetise a blade?

13th February 2005, 10:47 AM	#7
Jens Nordlunde Member Join Date: Dec 2004 Location: Europe Posts: 2,718	Hi all, Not all magnetite can become lodestone, it takes a special crystal structure, see what Dr. Peter Wasilewski, of NASA's Goddard Space Flight Centre, writes here http://www.phy6.org/earthmag/lodeston.htm this will answer some of the questions asked. Fearn, I am nor a specialist on this, but I would think, that if you fold a blade many times, it will loose magnetism. I agree with you, I also think the magnetism on blades was made later – but why? If we believe in what Dr. Peter Wasilewski writes, the lightening together with a good portion of superstition would lead them to believe that the Gods had made this metal. I don’t know if lodestone was ever used for weapons, maybe it was too difficult to get the iron out of the stone, or maybe the percentage of iron was too small, I don’t know – but one thing it could do, and that was making other iron weapons magnetic. If they believed that the Gods gave them this stone, they would also believe in, that using this stone to magnetize a blade would give the user more power. Nechesh, I know you did not advocating for magnetizing blades. I clean my blade and etch them, but I don’t magnetise them. The reason for this is that I don’t know if the blade was magnetised from the start, that is why I leave it be. Rivkin, it seems as if Dr. Peter Wasilewski does not agree with you about the magnetic felt of the earth when it comes to lodestone, maybe the magnetic felt could influence ancient pottery, I don’t know, and I don’t know the reason for this. I think you are right, that if any magnetism would be recovered in a blade after heating, it must cooled very slowly – just like the Indians did with wootz. The defects in crystalline structures, what other metal the iron was mixed with, even in very small doses must have been a problem for the smiths, as this would have affected the way the iron should be treated. It seems to me, that wootz from one ore might have needed a slightly different treatment than wootz from another ore, according to how the iron was mixed. But I never saw anywhere that the wootz ores were magnetic, only the lodestone. Robert, on the first link I gave, it somewhere say, that if you take a big nail which is not magnetised and hammer on one end for 50 times, the nail is magnetic – if you turn the nail and do the same on the other en of the nail, you will change the poles. Jim, I think a crude compass was made much earlier than about 11th century AD, try to read this: For many years magnetism was just a curious natural phenomenon and its only use was in navigation as what we now refer to as the mariner's compass and which was probably first developed by the Chinese some 4500 years ago. The earliest mariner's compass comprised a splinter of loadstone carefully floated on the surface tension of water. You can find the whole text here http://www.newi.ac.uk/BUCKLEYC/magnet.htm if you are surprised when reading this, I understand you – I was surprised too. Does anyone know if lodestone alone, or in combination with iron/wootz was used for making weapon? Interesting questions you ask – but you must remember that I am not an expert – I try to learn as fast as you ask the questions. yannis, interesting what you write to Jim, try to have a look on the link I gave him. Yes, filing on a blade can make it magnetic, but you would have to file in the same direction the whole time - not back and forth, and I think it would be an advantage if the file was magnetic. I doubt however if it would make a kard blade as magnetic as the one you have, but I don't know it. Jens

13th February 2005, 05:26 PM	#8
Rivkin Member Join Date: Dec 2004 Posts: 655	I believe that the case with Wasilevski is that his message have been probably perverted by "popular" explanation - probably what he meant is that extremely well magnetized samples have origins different from just being cooled in Earth magnetic field. Concerning the knowledge that ancient iron (whether in pottery, iron deposits or special spherical boxes lying on the ocean's floor) is magnetized alongside the Earth magnetic field at the time of the iron sample's cooling period is a well known fact, avoiding "real" papers I would bring your attention to: http://www.sciencetech.technomuses.c...fo_Magnets.cfm "Magnetite is magnetic because its molecular structure has allowed it to retain the alignment of particles caused by the Earth's magnetic field during its formation millions of years ago. When heated to high temperatures magnetite loses its natural magnetism. " http://www.tufts.edu/as/wright_cente...xt_plan_5.html "Finally, a fourth bit of evidence also favors the idea of plate tectonics, although here the data aren’t as robust, their implications not as clear. This evidence is supplied by paleomagnetism—the study of ancient magnetism. Everyday experience tells us that iron is magnetic; in fact, any metal containing even small amounts of iron ore is usually magnetized. However, when iron is heated to temperatures ~1000 K, it loses its magnetic properties as individual atoms jostle freely (which is why magnetic thermometers often fall off the side of a roaring wood stove). Hot basalt—the dark, dense stuff of volcanoes—impregnated with traces of iron and upwelling from cracks in the oceanic ridges, is thus not magnetic. As the basalt cools, magnetism sets in as each iron atom effectively responds to Earth’s magnetic field like a compass needle. When the basalt solidifies to form hard rock shortly thereafter, it fixes the orientation of the embedded iron, since the iron atoms align themselves with the orientation of Earth’s field at the time of cooling. Accordingly, the ocean-floor matter has preserved within it a history of Earth’s magnetism."