Copy letter, from Sir John Herschel to Edward Sabine, dated at Collingwood Copy of a letter. Invites Edward Sabine and his wife [at St. Leonard's] to visit . John Frederick William Herschel is impressed with Edward Sabine's ability to develop a working plan for terrestrial magnetism observations. Is prepared to write a review article [about magnetism?] if invited, but John Frederick William Herschel refuses to write such articles and offer them 'for acceptance or rejection.' 1858-7-1 or earlier