Pocket Compass.--A pocket compass should not be too small; if one of the
little toy compasses be carried in the pocket, it should be as a reserve,
and not for regular use. A toy compass will of course tell N. from
N.N.E., and the like; and that may be very useful information, but the
traveller will find that he constantly needs more precise directions. He
doubts the identity of some hill or the destination of some path, and
finds on referring to his map, that the difference of bearing upon which
he must base his conclusion, is small: he therefore requires a good sized
compass, to determine the bearing with certainty. One from 1 1/2 to 2
inches in diameter is practically the best. It should have plenty of
depth, so that the card may traverse freely, even when the instrument is
inclined: it should be light in weight, that it may not be easily jarred
by a blow; the catch that relieves the card, when the instrument is
closed, should be self-acting and should act well: lastly the movements
of the needle should be quick; one that makes slow oscillations should be
peremptorily refused, whatever its other merits may be: the graduation of
the degrees on the card should be from 0 degrees to 360 degrees, North
being 0 degrees and East 90 degrees. I wish some optician would make
aluminum cards. The material can be procured as foil, like tinfoil. It
can then be stamped and embossed, in which case it retains its shape
perfectly, but I cannot satisfy myself as to a good pattern, nor do I see
how to make the North and South halves of the disc sufficiently different
in appearance.
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