The Swimming Needles
There are several ways of making a needle float on the surface of the water.
The simplest way is to place a piece of tissue paper on the water and lay the needle on it; the paper soon becomes soaked with water and sinks to the bottom, while the needle is left floating on the top.
Another method is to hang the needle in two slings made of threads, which must be carefully drawn away as soon as the needle floats.
You can also make the needle float by simply holding it in your fingers and laying it on the water. This, however, requires a very steady hand.
If you magnetize a sewing-needle by rubbing it on a fairly strong magnet and float it on the water, it will make an extremely sensitive compass; and if you place two needles on the water at the same time, you will see them slowly approach each other until they float side by side, that is, if they do not strike together so heavily as to cause them to sink.