Letter, from Herbert Spencer to Sir John Herschel, dated at St. John's Wood Autograph letter signed by sender. Sending John Frederick William Herschel his Essays [Essays: Scientific, Political, and Speculative, 1857] and Herbert Spencer's 'Recent Astronomy and the Nebular Hypothesis,' the latter just published in the Westminster Review. Requests John Frederick William Herschel's comments on the latter publication. 10 January 1859