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 evolutie" (1956; English translation 1958 under the title "Creation and Evolution"). In 1970, Lever was elected member of the Royal Netherlands Academy of Arts and Sciences. In the early 1950s, Lever started research on the neuroendocrine system of the basommatophoran snail, "Lymnaea stagnalis". Lever himself found a particular kind of neurons in the ancylid snail "Ferrissia", and his student Joos Joosse demonstrated those neurons in other snail species. "Lymnaea" became the animal of choice for physiological research at the VU Amsterdam laboratory for decades. At the beginning of his career, Lever’s ideas about evolution and the species concept were inspired