The invention of the thaumatrope is usually credited to John Ayrton Paris. Paris was said to have used one to demonstrate persistence of vision to the Royal College of Physicians in London in 1824. Charles Babbage recalled in 1864 that the thaumatrope was invented by the geologist William Henry Fitton after he (Babbage) had told Fitton how the astronomer John Herschel had made him see two sides of a shilling at once by spinning it.[3]