. The London, Edinburgh and Dublin philosophical magazine and journal of science. where it will be at once seen that equal small variations in themagnetic force (horizontal direction) produce effects in themagnetization (vertical direction) dependent in amount onthe initial position on the curve. An apparatus found convenient in these experiments isshown in fig. 2. It consisted of an ordinary tambourine, Fig;. 2. gssggg. armed at the centre with a little piece of iron, and thus couldbe made to vibrate by an alternating current passed throughan electromagnet with a soft-iron core placed telepho
. The London, Edinburgh and Dublin philosophical magazine and journal of science. where it will be at once seen that equal small variations in themagnetic force (horizontal direction) produce effects in themagnetization (vertical direction) dependent in amount onthe initial position on the curve. An apparatus found convenient in these experiments isshown in fig. 2. It consisted of an ordinary tambourine, Fig;. 2. gssggg. armed at the centre with a little piece of iron, and thus couldbe made to vibrate by an alternating current passed throughan electromagnet with a soft-iron core placed telephonewiseclose up to the little piece of iron. The core could be perma-nently magnetized to the extent desired, either by a currentpassed through an additional coil wound on for the purpose,or by bringing up in line with the core a permanent magnetto a variable distance. 278 Dr. R T. Trouton on the Theory of Use of a With such an apparatus it is easy to arrange for showingthe gain in sound brought about by permanently magnetizingthe core of the electromagnet. For this purpose an alter-nating current is employed of insufficient intensity to affectthe diaphragm much ; one then brings up the permanentmagnet to the position shown in the diagram, on which thesound is found to be immensely improved. A similar resultof course can be obtained by a permanent current sent roundthe additional coil. To distinguish between the p
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Keywords: ., bookcentury1800, bookdecade1840, booksubjectscience, bookyear1840
