Zerah Colburn, American child prodigy, 1813.
© Science Museum / Science & Society Picture Library
Engraving by Henry Meyer after T Hull of 'A Child just eight years of age, endowed by nature with the remarkable faculty of solving a great variety of arithmetical questions by the mere operation of his mind.' Zerah (1804-1840) apparently had six fingers on each hand and 12 toes on each foot. He was able to carry out amazing feats of mental arithmetic: he was asked the question: How many seconds in 2000 years?, to which he replied '730,000 days, 1,051,200,000 minutes, 63,072,000,000 seconds'.