Electricity and magnetism
A technical textbook on electricity and magnetism by the Belgian engineer Eric Gérard, issued in English by W. J. Johnston of New York in 1897 for students and practising electrical engineers. The 31 plates are line diagrams: concentric circles with hatched rectangles, dashed spiral windings marked with angles, plus and minus signs ringing a coil section, and a hysteresis curve labelled with lettered points and arrows on J and H axes.
