Lessons in practical electricity; principles, experiments, and arithmetical problems, an elementary text-book . agneticoxide of iron (Fe3OJ because these, as taken from the earth,possessed the peculiar property ofattracting small pieces of iron orsteel. Later the Chinese discoveredthat if a piece of the ore were freelysuspended by a string it possessedthe important property of pointingalways in a particular direction,nearly north and south ; hence theygave it the name of lodestone (mean-ing leading stone), and used it in this manner to navi-gate their ships. Excellent iron is made from magneti
Lessons in practical electricity; principles, experiments, and arithmetical problems, an elementary text-book . agneticoxide of iron (Fe3OJ because these, as taken from the earth,possessed the peculiar property ofattracting small pieces of iron orsteel. Later the Chinese discoveredthat if a piece of the ore were freelysuspended by a string it possessedthe important property of pointingalways in a particular direction,nearly north and south ; hence theygave it the name of lodestone (mean-ing leading stone), and used it in this manner to navi-gate their ships. Excellent iron is made from magneticoxide of iron which is found in the United States (Arkansas)and various other parts of the world. In studying the mag-netic attractive force of a piece of lodestone by means of iron filings, it will be foundMm,.., vufii&MkimitT,. that the attraction for the filings seems to be cen-tered at two or morepoints on the stone,while at other points nofilings are Artificial Mag-nets.—The natural magnet possesses yet a third importantproperty, namely, that of imparting all of its properties to 1. Fig. 2.—Magnetised Steel Bar AttractingIron Filings. PRACTICAL ELECTRICITY. Copper Thread Wire a piece of hard iron or steel when they are rubbed togetherwithout apparently losing any of its original force. Thissteel (a piece of clock spring or a knitting needle willanswer) will now attract filings, when freely suspended cometo rest in a northerly and southerly direction, and can beused to magnetise another piece of steel. Strong artificial magnets are not made from the lodestone,as its magnetic force is not strong, but by better methods tobe mentioned later. Figs. 1 and 2 illustrate a natural andartificial steel magnet attracting filings. 3. Definition of a Magnet.—Given two pieces of similarsteel, one of which is a magnet and the other not magnetised,how would you determine the magnet ? Plunge each pieceof steel into iron filings ; only the magnetised bar will attract them
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