Various illustrations of magnetic fields and electric charges for an educational book.

Illustrations that help explain electrical charges and magnetic fields.

... and some more illustrations.

Illustrations of the “corkscrew rule” (right-hand rule), coils, fields and charges.

Illlustrations for publication ‘Elementaire Elektrotechniek’

Spruyt, Van Mantgem & De Does in Leiden, or ‘SMD Educatieve Uitgevers’ in short, publishes school books for all educational levels.

Jan van Es [design] made hundreds of illustrations for the educational publication ‘Elementaire Elektrotechniek - Elektrische en magnetische velden’ by P.J.G. Ballhaus, A.J.G. Goris and T.J. Kleintjes.