This section is from the book "The Boy Mechanic Vol. 2 1000 Things for Boys to Do", by Popular Mechanics Co.. Also available from Amazon: The Boy Mechanic, Vol2: 1000 Things for Boys to Do.
After trying to tell a few small boys what a compass is, they wanted a practical illustration - something they could see. Not having a compass or knowing where to locate one handily, I used a piece of cork with needles and a needle for a pivot and found it very satisfactory. The method used is shown in the sketch.
It is best not to magnetize both needles unless care is exercised in maintaining pole relationship, or they will oppose each other and not point to the north. The extreme ends or the heads of the needles must be opposites, the head of one negative and the head of the other positive.
If a good compass is brought care- lessly in contact with a magnet, the poles may become reversed and the north end will no longer point to the north but to the south until the current has been reversed again by bringing the opposite pole of the magnet in contact with the compass. - Contributed by W. H. Albright, Bellevue, O.
Ill: Two Large Needles in a Cork Balanced on a Central Needle to Make Them Revolve Easily