Re: compass changing polarity!!

Peter Clinch wrote:

Eugene, you're a knowledgeable guy but I would suggest that Silva quite possibly know rather more about this than you do. Furthermore, it's hardly that difficult to ask them directly yourself if it ever happens, if it does then how often it does, and also what can be done about it.

Following up my own post, surf to http://www.silva.se/outdoor/products/comp_general.htm and we find the following text:

"Reversed Polarity

Golden Rule - Any make or type of magnetic compass, should be kept well clear of magnets and magnetic fields.The SILVA compasses are manufactured in the non-magnetic compass factory in Sweden.

Cause - Magnetic fields exist around, some car seat belts, electrical circuits, etc. and RAPID movements within inches of these items, or even ferrous (containing iron) metal, an iron gate or fence for example, may affect polarity of the needle.

Effect - The needle either becomes sluggish and slow to settle (it may appear to stick and look out of balance) if its polarity is partially reversed, or may reverse its polarity completely. In the latter case, the "North" (usually red) seeking end of the needle will point South.
Cure - Quickly stroke the "South" pole of a strong magnet outwards along the "North" end of the needle. Repeat vice-versa. Compare with a compass that is known to be correct."

Pete.
--
Peter Clinch                    Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637   Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177              Dundee DD1 9SY Scotland UK
net p.j.clinch@xxxxxxxxxxxx     http://www.dundee.ac.uk/~pjclinch/

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