Ampère’s cats

The mistakes of greater and cleverer men are a lesson and a consolation to us. Ampère had two cats for company, one larger than the other. But at times they disturbed the great physicist in his work because he had to open the door so that they could go in and out repeatedly. So he simply equipped the bottom of his door with two smaller openings—a big one for the large cat and a little one for the smaller cat. Let us be grateful to Ampère.

—Richard Willstätter