Willem Jacob 's Gravesande

http://en.wikipedia.org/wiki/Willem_Jacob_%27s_Gravesande

http://www-groups.dcs.st-and.ac.uk/history/Biographies/SGravesande....

http://www.evi.com/q/willem_gravesande

Dutch mathematician and physicist. He improved experimental physics by clear demonstration tests, for example the ‘ball and ring of ‘s Gravesande’ to show the expansion of metals when heated. For his experiments and discoveries he used instruments made on his behalf by Jan van Musschenbroek. ‘s Gravesande laid the foundations for teaching experimental physics.

's Gravesande (27 Sep. 1688-28 Feb. 1742) was one of the scientists who was honestly convinced that the construction of a perpetual motion machine is possible. He lived at the hayday of the PMM delusion. What were the reasons? Mechanical arts and skills were, compared to previous centuries, far more developed. Engineers like Ramelli or Leupold published large volumes which systematically collected machine descriptions. Although some of these constructions seem to be of less practical value from today's point of view, there seemed to be only a few mechanical tasks that could not be solved. One of the reasons for the opinion that a PMM is possible was Descartes' theory that a falling body wins force on its way. From our point of understanding, this is a confusion of force and impulse. But under the assumption that Descartes was right, it could be proved that a PMM was possible. s' Gravesande followed this opinion, until he learned of Newton's gravitational law. Newton could also show that Descartes' theory of force was based on a misunderstanding. s' Gravesande was one of the first scholars on the continent who actively engaged himself in making Newton's theory popular. The theory of gravitation proved to be a very powerful concept. Unfortunately, 's Gravesande had examined Bessler's machine and already written a positive scientific essay. As the fraud was uncovered, 's Gravesande escaped into flimsy excuses. In fact, he was no more convinced of the creation of perpetual motion by human hands. Let's say, in the mechanical area. As far as (Al)chemy was concerned, he still expected unknown possibilities to reach that aim.