Integraph

An Integraph is a mechanical analog computing device for plotting the integral of a graphically defined function. An Integraph is a mechanical analog computing device for plotting the integral of a graphically defined function. It was invented independently about 1880 by the British physicist Sir Charles Vernon Boys and by Bruno Abdank-Abakanowicz, a Polish-Lithuanian mathematician/electrical engineer from the Russian Empire. Abakanowicz's design was constructed by Coradi of Zurich. The input to the integraph is a tracing point that is moved to trace the input curve. The output is defined by the path a disk that rolls along the paper without slipping. The mechanism sets the angle of the output disk based on the position of the input curve: if the input is zero, the disk is angled to roll straight, parallel to the x axis on the Cartesian plane. If the input is above zero the disk is angled slightly toward the positive y direction, such that the y value of its position increases as it rolls in that direction. If the input is below zero, the disk is angled the other way such that its y position decreases as it rolls.