Max Ringelmann

Maximilien Ringelmann (10 December 1861, Paris – 2 May 1931, Paris)^: 55 was a French professor of agricultural engineering and agronomic engineer who was involved in the scientific testing and development of agricultural machinery.

Ringelmann's interests were wide-ranging: he developed the Ringelmann scale which is still used to measure smoke. He also discovered the Ringelmann effect in social psychology, viz, that when working in groups, individuals slacken.