Fig. 8.—The Attraction of an Iron Nail through Glass.
It will also attract through glass, wood, brass, and all other substances. Through an iron plate, however, the attraction is reduced or entirely checked because the iron takes up the magnetic effect itself and prevents the force from passing through and reaching the nail.
A number of carpet-tacks may be supported from a magnet in the form of a chain. Each individual tack in the series becomes a temporary magnet by induction.
If the tack in contact with the magnet be taken in the hand and the magnet suddenly withdrawn, the tacks will at once lose their magnetism and fall apart.
Fig. 9.—A Magnetic Chain.
It will furthermore be found that a certain magnet will support a certain number of tacks in the form of a chain, but that if a second magnet is placed beneath the chain, so that its south pole is under the north pole of the original magnet, the chain may be lengthened by the addition of several other tacks.
The reason for this is that the magnetism in the tacks is increased by induction.
Magnets will Attract or Repel each other, depending upon which poles are nearest.