Balthazar van der Pol, Dutch electrical engineer, c 1930s.
© Science Museum / Science & Society Picture Library
Etching of Balthazar van der Pol (1889-1959). Van der Pol was interested in experimental dynamics. He built a number of electronic circuit models of the human heart to study the range of stability of heart dynamics, in the hope of discovering how to stabilise irregular beating. Published by the International Telecommunication Union (1955-1964). Dimensions (overall): 230mm x 190mm.