Rensselaer Semi-Weekly Republican, Volume 41, Number 64, Rensselaer, Jasper County, 30 April 1909 — Electro Magnets. [ARTICLE]

Electro Magnets.

The familiar horseshoe magnet is made of highly tempered steel and magnetized so that one end is a north po}e, the other a south, or pernaps more commonly known as a negative and a positive. Once magnetized it is always magnetic unless the power is drawn from it by exposure to intense heat. An electro-magnet, however, can be made from any scrap of soft iron, from a piece of ordinary telegraph wire to a gigantic iron shaft. When a current of electricity passes through an insulated wire coiled about’ a soft iron object, such as a nail, a bolt or a rod, that object becomes a magnet as long as a current of electricity is passing through the colls of wire or helix. A coil of wire in the form of a spiral spring has a strpnger field than a straight wire carrying the same current, for each turn or convolution adds its magnetic field to that of the other turns; and by having the center of the coil of iron, which is a magnetic body, the strength of the magnetism is greatly ihcreased.- :;; Bf. N4ehdlS^”