electromagnetism

[English electro, and magnetism.] The science which treats of the development of magnetism by voltaic electricity, and the properties or actions of the currents thus evolved. Profe or Oersted, of Copenhagen, led the way in the discoveries which established the science; Ampère, Faraday, Barlow, Arago, Nobili and others followed in his track. The temporary magnetic moment is proportional to the intensity of the currents. In the case of an iron bar it is proportional to the number of windings. In a magnet it is proportional also to the square root of the diameter of the magnet. In solid and in hollow cylinders of the same diameter it is equal in amount. The attraction of an armature by an electro-magnet is proportionate to the square of the intensity of the current, as long as the magnetic moment does not attain its maximum. Two un equally strong electro-magnets attract each other with a force proportional to the square of the sums of both currents. For powerful magnets the length of the branches of an electromagnet is without influence on the weight which it can support. ĕ-lěc-tro-măg'-net-ist, s . One versed in electro electro-medical, a . [English electro , and med ical.] Pertaining to electricity used medically; designed to cure diseases by means of electricity. (Ganot.) magnetism. electro-medical apparatus, s . An instrument for the treatment of diseases by electro-magnetism. electro-metallurgy, s. [English electro , and metallurgy .] The act of precipitating metals from their solutions by the slow action of a galvanic current. The method of doing this was discovered independently by Spencer in England, and by Jacobi in St. Petersburg. ( Ganot.) IMG:content-0847.png:[blocks in formation] electro-metrical, metrical.] Measuring electric force; pertaining to electrometry.