6 
A MANUAL FOR NORTHERN WOODSMEN 
line some feet away, and then look through the sights upon 
it. If the plumb line appears to traverse the forward slit 
exactly, that sight is in adjustment. If not, file off the base 
of the sight until the adjustment does come. Then revolve 
the compass 180° and test the other sight in the same 
manner. 
3. Keeping the Compass in Order 
Sharpening Pivot. The pivot or center pin of a compass 
much in use is liable to become dulled so that the needle 
does not swing freely. To obviate this the needle should 
always be raised off the pivot when the compass is being 
carried. A much blunted pivot should be handed over to a 
jeweller to be turned down in a lathe, but ordinary sharp¬ 
ening can readily be accomplished by the surveyor him¬ 
self with the aid of a fine whetstone and the small wrench 
usually supplied with a compass, or a pair of pliers. The 
pivot should be removed from the compass box and fixed 
in the end of a small, split stick; the point may then be 
sharpened by twirling it gently on the stone at an angle of 
about 30° with its surface. When the point is made so 
fine and sharp as to be invisible to the eye, it should be 
smoothed by rubbing it on the surface of a soft, clean 
piece of leather. 
Remagnetizing Needle. Dulness of the needle may 
be due to the fact that it has lost its magnetism and needs 
to be recharged. For this purpose a permanent magnet is 
required. The north end of the needle should be passed 
several times along that pole of the magnet which attracts 
it, and the south end passed similarly over the opposite 
pole. The passes should be made from center to end of 
the needle, and a circle described in bringing the two ends 
successively into contact. In order to prevent the loss of 
magnetism, the needle of a compass not in use for a con¬ 
siderable time should lie in the north and south direction. 
Balancing Needle. The needle is commonly balanced 
on the pivot by a fine brass wire wound around the south 
end. If change of latitude is made, the balance will be 
destroyed, and the wire may be shifted to make adjustment. 
Replacing Glass. In case of emergency, a piece of win- 
