From 1777 to 1783 James Boswell was a columnist for the London Magazine, writing a total of seventy essays under the pseudonym the Hypochondriack.
Johannes David Hahn - Professor of Philosophy and Natural Sciences
Johannes David HahnBorn 1729
Professor of Philosophy and Natural Sciences at the University of Utrecht (1753-1775), and Director of the Botanical Garden at the same place (1759-1775). Professor of medicine and chemistry at the University of Leyden (1775-?). According to Boswell in Holland 1763-64 he was the sometime physician to Belle de Zuylen.
Boswell heard Hahn lecture about Nitre (a chemical used for the making of gunpowder) at Utrecht on January 19, 1764. On April 8 Boswell supped at the professor's with whom he also met on May 21. On this last occasion, Hahn "told stories of Rücker's forgetting law, and officer hearing voices blaspheming".