The tenth volume in the series presents a hitherto overlooked item in the oeuvre of the famous discoverer of electromagnetism, Hans Christian Ørsted (1777–1851). A highly influential figure in cutting-edge science internationally, Ørsted was also active as a populariser of various kinds of academic discoveries and theories within nineteenth-century Denmark. However, no separate publication on the aurora borealis by Ørsted has been known until now. It is in one of the many contemporary collections of miscellanies for the general public – namely, in Dansk Folkekalender for the year 1841 (printed 1840) – that Kira Moss has discovered his unsigned article on “Nordlyset” [The Northern Light]. In her introduction, Moss presents evidence of Ørsted’s authorship, contextualises the place of the northern lights in Denmark in the period known as Romanticism, and presents a detailed summary of his own theory. As a supplement, she provides a complete English translation of Ørsted’s article.