Old University Library (Erlangen) — Photo Credit: By Akriesch 20:42, 28 June 2006 (UTC) (auch de:Benutzer:Akriesch) - Own work, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=903663
Faraday's Electromagnetic rotation experiment — ca 1821 Photo Credit: By Michael Faraday - Experimental Researches in Electricity (volume 2, plate 4), Public Domain, https://commons.wikimedia.org/w/index.php?curid=4134268