Ahh, Tom, where would we be without your leaps of assumption and splendid ignorance of reality?

a bog-standard Silva compass. as made in sweden. (that's a country with much of its land mass in the arctic circle, for those of us who adhere to Real Earth geography, by the way)
It served me very well, pointing to the north and south poles from as far north as Tromso in norway (well beyond the circle) and as far south as New Mexico... its still probably in my parent's house all these years later. somewhere.
Unfortunately, "dip compasses" as you put them are, in fact something
completely different to what your deranged imagination seems to envisage: they are in fact fixed in their rotation on the horizontal plane, so they may only rise and lower in the vertical plane - or dip downwards. they were used by geologists to find magnetic deposits. they are not in any sense used by rational man, beast or duck, a device used for dertermining north, in such a configuration. Many dip compasses, however, could be physically moved from vertical to the horizontal plane to be used as normal compasses.

is a pic of one such device.
the change in field in differnt regions can be read here:
http://www.wide-screen.com/Suunto/zoneInfo.shtmlif, for once in your life, Tom, you actually want to learn something about what you're pretending to appear to know something about, instead of simply talking nonsense.