Highfield lever Highfield lever A Highfield lever is a lever device which allows tension to be rapidly set up in a wire and equally rapidly released to the required extent. It is frequently used in sailing boats where tension in some part of the rigging needs to be adjusted to a pre-set amount as the wind impinges on one side of the sails or the other. It is typically used in running backstays (runners). To make it work, the backstay is led through a block or fairlead along the deck to a two-legged, second order lever mounted with its fulcrum above deck
Jan Lever by the Reformational philosophy of philosopher Herman Dooyeweerd. During his student days, Lever became acquainted with the biologist Johann Heinrich Diemer, who had published about Dooyeweerd's approach in the domain of biology in the 1930s. Diemer was a great influence on Lever's thought. Together with Dooyeweerd, Lever wrote four articles about the species concept in the journal "Philosophia Reformata" (1948–1950) in which species were defined as constant types. In his book, "Creatie en Evolutie" (1956), Lever still subscribed to Dooyeweerd’s philosophy but also suggested that it is possible that biological evolution occurred. Later he moved away from these earlier ideas