Letter, from Sir Charles Lyell to Sir John Herschel, dated at 53 Harley St. Autograph letter signed by sender. Took John Frederick William Herschel's box of specimens and had a discussion with William Logan, A. C. Ramsay, and some young surveyors, one of whom had examined John Frederick William Herschel's neighborhood. Similar rhomboids to the Irish ones have been located in Wales. Hopes to have a discussion on this subject later. Can John Frederick William Herschel give, or refer him to data, the temperature of celestial space without the sun? Returns the drawings with many thanks. 4 March 1865