Letter from John Frederick William Herschel, 32 Harley Street to Edward Sabine Herschel thanks Mrs [Elizabeth Juliana Leeves] Sabine for the translation of the third volume of Alexander von Humboldt's Cosmos and admires his work. Herschel questions [Humboldt’s] references in notes. Refers to [Samuel Heinrich] Schwabe’s ‘period of ten years for solar spots’ and the ‘periodicity of the sun’ [referring to the solar cycle]. Discusses meeting for Wintringham Committee. 15 March 1852