An apparatus invented by Francis Galton (illustrated below) consisting of a glass-faced case containing an upper reservoir where balls are stored. Below the reservoir are arranged row after row of equally spaced pegs that stand out from the wall, and below these is a series of vertical slots. The balls are allowed to fall one at a time through a central opening at the bottom of the reservoir. Since each ball after striking a peg has an equal probability of bouncing to the left or right, most will follow a zigzag course through the pegs and will eventually land in a central slot. The final distribution of balls in the slots will be a bell-shaped one. The apparatus demonstrates how the compounding of random events will generate a family of bell-shaped curves. See Chronology, 1889, Galton.
Subjects: Genetics and Genomics.