| Description | Contemporary copy in sender's hand, signed by sender. Critiques John Henry Dallmeyer's paper on plant chemistry, contrasting 'luminous, colorific, calorific, and chemical or photographic' rays. Physics of light. [Letter continues two months later.] John Frederick William Herschel is done with photography. Has no desire to claim priorities in that field. Entrusts future to John Henry Dallmeyer and others. |
| Place origin | Collingwood, Hawkhurst, Kent |