Letter, from Henry Oldenburg to Eramus Bartholin, dated at London That Thomas Henshaw (1618-1700) would be a good person to ask about the activities of the Royal Society since he works in Denmark; lists recently published works by Fellows; wishes for Bartholin's opinion on Picard's work who has just published a book on the measurement of the earth; would also like Picard's observations at Uraniborg; wishes to know what Bartholin is working on and how far the edition of the works of Tycho Brahe has advanced; that the bearer of the letter would be able to recount Newton's method for shortening telescopes 21 February 1672