1-155-544 - Ann Ronan Picture Library/Heritage-Images

Behaviour of a magnetic compass, 1643. If a compass in a box is carried round a globe-shaped magnet (N, centre of picture) with magnetic poles where lines cross (left and right of N), magnets ab at C and D can be set in any position as they are directly between the poles. From Magnes: sive de arte Magnetica by Athanasius Kircher. (Cologne, 1643).