Letter from [Sidney Bertram] Gaythorpe, Bonnington Hotel, Southampton Row, London, W.C.1., to [Francis Alexander] Towle, Assistant Secretary, Royal Society, Burlington House, W.1 Reminds the Royal Society of his previous visit when his research was focused on [John] Wallis and Horrocks, and informs he has recently come across an interesting document in the Sloane Collection at the British Museum, which he believes was written by Nicolaus Mercator FRS. Enquires whether the Royal Society holds any autographed records by Mercator to enable him to verify. 7 May 1923