Archive for the 'Instrument/Pointer' Category
A magnetized pointer in a round piece of cork dips and deviates in a water bowl
Friday, May 27th, 2011[ZB Magnet 2] William Gilbert, De Magnete (London: Petrus Short, 1600), Zentralbibliothek Zürich, Alte Drucke und Rara, p. 203.