Kircher’s Sunflower Clock


" To illustrate his belief in the magnetic relationship between the sun and the
vegetable kingdom, Kircher designed this heliotropic sunflower clock by
attaching a sunflower to a cork and floating it in a reservoir of water. As the
blossom rotated to face the sun, a pointer through its center indicated the time
on the inner side of a suspended ring. Kircher claimed that it didn’t work well
because enclosing it in a glass case would block the sun’s attractive force, and
that it was ‘therefore susceptible to inaccuracies due to the wind’. Further,
“when the sunlight was weak, and itself was as if withered and worn out, it ran
slow, seeking rest.”

Proceedings of the Athanasius Kircher Society