Looking up Foucault's pendulum experiment in Meyers Grosses Taschenlexicon, I read the claim that Vincenzo Viviani in 1661 was the first to do the experiment, 189 years before Foucault! Browsing through the Web for more details, I was only able to find two further references: In http://www.newadvent.org/cathen/15183a.htm "Foucault's pendulum experiment was materially forestalled [sic] by Viviani at Florence (1661) and Poleni at Padua (1742), but was not formally understood." and in http://www.physik.uni-greifswald.de/~sterne/Observatory/events.html "Already in the year 1661 Vincenzo Viviani discovered this phenomenon. It was rediscovered by Leon Foucault in 1850."
I'm hoping some of the erudite contributors to this group can give me a few more details. It seems like the experiment, while requiring some care, should have been within the range of 17th century technology. Did Viviani really look for rotation of the plane of swing of a pendulum? Did he know it would provide the proof of the Earth's motion that eluded his mentor Galileo? Did he get a positive result? Why was the experiment forgotten for almost two centuries? Thanks and best regards, Art Carlson P.S. I come to this question because I am reading "Galileo's Daughter" by Dava Sobel. I thought that the interest shown in this forum for her book on "Longitude" was justification enough for asking my question here. In addition, there are some connections with sundials through the time-keeping aspects of pendulua and through Galileo's attempts to solve the longitude problem using the moons of Jupiter. Apropos Sobel's new book, I'm a third of the way through. Up to now it's a remarkably straightforward biography of Galileo. It certainly won't have the fascination for this list that "Longitude" did.
