Letter, from Henry Oldenburg to [Christiaan] Huygens, dated at London Concerning the flight of spiders; concerning the 50-foot telescope; concerning the success of Huygens' clocks on a voyage to Crete; concerning Campani's clock; concerning the discovery of longitude under the scrutiny of the Paris academy; concerning Boyle's experiments with water in pipes; concerning Barrow's work on optics 11 November 1669