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HOME-MADE TOYS FOR GIRLS AND BOYS
The first part of the toy to construct is
The Electro-Magnet. The difference between an electro-magnet and the toy variety of horse-shoe magnet with which every boy is familiar, is that the electro-magnet retains its magnetism only so long as an electric current is passing around it, while the steel magnet retains its influence permanently, after being magnetized, unless it happens to be demagnetized by subjection to heat, or in some other way.
Fig. 176.—An Electro-Magnet Derrick.
Figures 177 to 179 show the details for making a simple home-made electro-magnet.
