Letter, from Sir John Herschel to Mary Somerville Autograph letter signed by sender. [Augustus] DeMorgan and [Henry Fox] Talbot are sending their papers to her. John Frederick William Herschel sends her his report on "Atmospheric Waves and Meteorological Districts" [for the British Association]. Family is well. Outlines a process for transferring photographic impressions on paper to glass, as described in the Athenaeum. 1845 ?.