Magnetic weapons

[Rivkin]

And it would not make a bit of difference to make swords from lodestones - they would lose their magnetization, just as any other piece of iron, during the heating process.

[capt.smash]

HI i might be out of my depth here but im sure i heard that if you take 2 pieces of metal and stroke them together in the same direction continualy for a long ..long time they eventualy become slightly magnetic[a labour intensive version of strokeing a piece of metal in 1 direction with a magnet ]..i have noticed this in old drillbits that develop magnetism from spinning continualy in 1 direction against metal.[i asume this is why they become magnetic]?
Perhaps smiths who use metal files could inadvertantly cause magnetism in blades from useing a file in this method, gradualy magnetiseing the file and then whatever blade he works on [this is relying on him haveing a fileing technique where he files only on 1 direction and lifting the file on the return stroke ]i see this fileing technique in woodwork but not sure about metalwork.
Also mabe this could be the case for a stone sharpeing/grinding wheel[if it had a slight metal content]?Also this might explain why some blades have diffrent strength magnetism on diffrent parts of the blade that required more fileing.
This may sound silly but i thaught id mention it .

[Jens Nordlunde]

Rivkin, you explanation sounds most interesting, as well as you links, which I will read - and hope I will understand .

I must say, that I am overwhelmed by the inputs and the quality of the inputs, thank you very much.

capt.smash, no you are not out of your depth, on the contrary. You are dead on mark. Yes the fils must be used only in one direction, or it wont work. All the litte pieces of iron would be all confused otherwise . Thank you for answering.

Jens

[Mare Rosu]

JENS and all others good forum folks.
A most interesting thread indeed. I find little to fault with all the input but I have a question: How can one have two or more magnetic poles on the same blade? If you use a file, hammering or other means to magnetize a blade on purpose or otherwise, would you not have just one pole a North and a South pole on the blade. It is hard for me to figure out a process that would magnetize a blade with more than one North,& South pole without doing so on purpose by someone along the way. Leaving it in one place even for hundreds of years would still give you just a North and a South pole.
So my take is that a blade with more than one North and one South pole must have been done so on purpose.
Gene
Sorry Fearn got it right this time.

[Jens Nordlunde]

Gene, you got it absolutely right - the way you describe it, is the way it must have been done - on purpose .
Now the big question is why, and I doubt veru much that anyone can answer this question, unless we find some hints in old books. Should I find them, be sure that I will let you know.

Jens

[Rivkin]

Most likely purpose have absolutely nothing to do with it. Anvil and hammer assuming they are magnetized (which is quite a logical assumption), they can create a very weird magnetic patterns in the forged blade. Not taking into account interactions in between of different parts of the blade, differential heat treatment, different chemical compositions.

[Jim McDougall]

This thread really is more and more fascinating!!
Yannis: thank you for the additional notes on Magnesia. I did see the reference to both regions when I read the entry in Brittanica, but left out that detail for simplicity in general reference. It seems to me the reference to the Cretan shepherd may likely be apocryphal. As always, I would defer to your outstanding knowledge of your country's history.

Jens: I have read the material on the link referring to Chinese mariners compasses being used some 4500 years ago, but cannot find anything to support the authors statement. Most of my research is based on Encyclopedia Brittanica data which notes (under 'compass') "...there is no genuine record of a Chinese maritime compass before 1297 AD as Kalproth admits".
*"Letire a' M.LeBaron Humboldt sur l'invention de la boussele" J. Kalproth, 1840, p.57 (bossola=It. term for compass, used by Muslims).
The Brittanica states further that the earliest allusion to the power of lodestone in Chinese literature occurs in a Chinese dictionary in 121 AD defining the stone as giving attraction to a needle. There is however myth suggesting a Chinese emperor created a chariot to indicate south (the Chinese compasses focused south, while European north) and the four cardinal directions, c.2634 BC. This period would fall loosely into that suggested in the material noting 4500 year old date, but it would seem that data remains largely subjective.
Naturally more recent research has discovered considerable new material concerning early Chinese maritime history as we have found in the book "1421", so more must be considered before any conclusions can be drawn.

Concerning the use of lodestone in smelting steel:
Robert Elgood in "Arms & Armour of Arabia in 18th & 19th c." on p.107 states. "...Birdwood (1880) wrote that 20 miles east of Nirmal and a few miles south of the Shisha hills occurs the hornblende slate or schist from which the magnetic iron used for ages in the manufacture of damascus steel, and by the Persians for their swordblades is obtained."
"The Industrial Arts of India" G.C.M.Birdwood, London, 1880, p.50

Elgood also notes on p.86 that HH Sultan Ghalib Al Qu'aiti described to him how magnetic quality found in some dagger blades raised the esteem of the blade. He notes that the very best janbiyya and nimsha blades were imported into the Hadhramaut from Hyderabad where they were made. These blades were referred to generally as 'Haiderabad'.

It would seem that magnetite was certainly present in certain wootz from India, although not necessarily in all of it. It is noted that wootz was also of course smelted in Kona Samundrum (southern India) where much of this product was exported particularly to Persia as the raw material in cakes.
It is not specified that any magnetic properties existed in this form of wootz.

I think the observations concerning creating magnetic polarity by filing consistantly as described is interesting, and while certainly non relevant to magnetism, I think it is interesting to note that the force of static electricity also creates the property of attraction in textiles. With the forces of nature, and as we well know in the aviation industry, static electricity can be deadly near volatile materials. On a lesser note, the same force can be maddening for women wearing certain clothing on a dry, windy day .. the dreaded static cling!!

Now ask me as I sit in the rubble of notes and stacked books here in my den, how in the world did I get from ancient Chinese navigational history and the production of steel in India to static cling in womens skirts!!?
I need some rest !!!

Best regards,
Jim

[Jens Nordlunde]

Originally Posted by Rivkin

Most likely purpose have absolutely nothing to do with it. Anvil and hammer assuming they are magnetized (which is quite a logical assumption), they can create a very weird magnetic patterns in the forged blade. Not taking into account interactions in between of different parts of the blade, differential heat treatment, different chemical compositions.

Yes that could be a possibility, but (sorry, I know all the 'buts' are iritating) if it was the hammer and the anvil, why are so few blade magnetic?
Different heating and maybe different chemicals used, as we do know they used different chemicals, could also be part of the process, but again, if so, why do we have so relativly few magnetic blades?

Yannis, the way I see it, I think you are comming frightfully close - but I am guessing, I can't prove it . Your mail made me remember something said about enamel making, it was either in Jeypore Enamels, 1886, by Jacob and Hendley, or in Indian Art at Delhi 1903, by Watt. In one of the places the author writes that some of the secrets about enemal making has been told by a named Englishman, and the authors attitude was that he should not have told the secrets.
If the attitude of the early writers was 'let the artists keep their secrets', one can not wonder why we find so few hints about magnetism in the books.

We still have a puzzle or two, and one is Gene's blade. Why does the magnetism change four times? I have been told that it is no problem to do this, but there must be a reason for someone to use his time to make the blade magnetic like it is .

Jens