Gilbert on electrostatics. Page from 'De Magnete' (On the Magnet, 1600) by English physicist William Gilbert (1544-1603). The diagram shows experiments conducted by Gilbert with a versorium (electrically charged needle) and a magnetised sphere (terrella, 'little Earth'), distinguishing between magnetism and electricity. 'De Magnete' reported Gilbert's studies of magnetism and electricity. He theorised that the two forces were closely related. He also considered the Earth to be a spherical magnet. This first edition of 'De Magnete' consisted of 115 chapters in six books and 246 pages. This is page 148, chapter 17, book 3.