Letter, from Richard Sheepshanks to Sir John Herschel, dated at Athenaeum Autograph letter signed by sender. Suggests that John Frederick William Herschel assist William Lassell's travels to Malta by asking for a letter of introduction from the Duke of Northumberland; is concerned about the precarious position of the observatory at Altona, and of the Astronomische Nachrichten published there. 14 May 1852