Letter, from Henry Oldenburg to Martin Fogel, dated at London Thanks for the account by Sivers of observations of sunspots; encourages more correspondence, particularly detailing lines of enquiry for observing the Harz mountains; concerning the astronomical correspondence which have been received from Cassini, Boulliaud, Huygens and Hevelius; wishes for a copy of a biography of Galileo and that he will send it to Fogel in due course; concerning his enquiry about Pocock's work on coffee and whether he knows anything about frankincense tree and myrrh; concerning the enquiry about bdellium 14 November 1671