Traitté de l'aiman : divisé en deux parties: la première contient les expériences, la seconde les raisons que l'on en peut rendre
A 1691 French treatise on magnets by Joachim d'Alencé, a scientific textbook presumably for learned readers, divided into experiments and explanations of their causes. The engravings are small, numbered plates showing magnetic experiments, with a hand holding a magnetized stone above a needle, a floating magnet on a dish, and a magnetic field drawn as dotted lines around a stone, which a designer could take as a clear, diagrammatic vocabulary for showing invisible forces.
