From the history of physics
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FROM THE HISTORY OF PHYSICS
The first electromagnets appeared shortly after Christan Oersted discovered the magnetic effect of electric current in 1820. Already in the autumn of the same 1820, Ampere came up with an iron-free electromagnet - solenoid (the name of this was also introduced by Ampere). Three years later, a small English physics teacher, Sturgeon, invented, manufactured and shows in his lectures the first real electromagnet in the form of a varnished iron rod (see Fig.) with a wire wound on it.
dragging The varnish served as electrical insulation. As the achievement progressed, it was possible to hold several tens of grams of iron with this electromagnet. Sturgeon also made the first horseshoe-shaped electromagnet, which could hold a load of more than 4 kg.
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