Manual of Magnetism, Including Galvanism, Magnetism, Electro-Magnetism, Electro-Dynamics, Megneto-Electricity, and Thermo-Electricity.

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1865 Excerpt: ... is removed to a distance from the magnet. 236. The inductive action of a magnet is not impeded by the interposition of any unmagnetizable body whatever. If a plate of glass be placed between the magnet and a piece of iron, the iron is attracted as strongly as it would be at the same distance with no glass interposed. Pig. 99 represents a piece of iron wire, sealed up hermetically Fig. 99. in a glass tube. When this is applied fe to a U-magnet, the iron is attracted with UlrM suffiCent force to hold the tube in conlil III tact wtn e Pes# ne polarity inIll pH duced in the iron is precisely as great as when only air is interposed. The result is the same when the iron is en) closed in a tube of brass, or any metal not susceptible of magnetism. 237. Fig. 100 represents an instrument designed to measure the force of attraction between a Umagnet and its armature at different distances. It Fig. 100. rpnn-H'i Ii Ii in iffPiiii w mi wm m t&' is on the principle of the steelyard. The beam, which is of brass, is supported by steel knife edges, resting in curved supports of the same metal. To the shorter arm of the beam is secured the armature, consisting of a small cylindrical bar of iron. The force with which this is held down is measured by weights hung upon the graduated longer arm. The magnet is held firmly against a vertical brass plate, by means of a clamp of the same metal, which allows the poles to be fixed at any required distance from the armature. The distance was determined in the following way: Sheet brass of of an inch in thickness was taken, and several series of different thickness formed by pressing strips of it firmly together and soldering them at the edges. By interposing these strips between the magnet and armature, they were maintained at any...