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Jared wrote:

> One assumes the problem of compass tilt and north/south zones would not
> apply to the (usually cheap) ball-type compasses where the "card" is
> actually a white ball, free to move in any direction, i.e. the inexpensive
> ones sold for car dashboards and zipper pulls.


I disagree. If the very-cheap compasses sold as novelty items did not
have counter-weighting based on some assumed dip angle, they wouldn't
point north in Canada and the northern U.S. They would point _down_ --
maybe 15 to 25 degrees off straight down. I doubt that such a compass
would enjoy many sales, even as a novelty.

> I suppose aviation compasses would come closest to this same solution, in a
> better quality compass.

Maybe. Or do aircraft simply carry gyros? With abundant power available
and the higher cost of the basic vehicle (aircraft vs. boat) making a
gyro relatively cheaper, why fuss with a magnetic compass?


Trevor Kenchington



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Trevor J. Kenchington PhD                         Gadus@iStar.ca
Gadus Associates,                                 Office(902) 889-9250
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Nova Scotia  B0J 2L0, CANADA                      Home  (902) 889-3555

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