Letter, from William Henry Fox Talbot to Sir John Herschel, dated at Greta Bank, Keswick Autograph letter signed by sender. Willingly gives John Frederick William Herschel permission to engrave a portrait photograph taken with William Henry Fox Talbot's process. William Henry Fox Talbot asks John Frederick William Herschel if he would be willing to testify on William Henry Fox Talbot's behalf if necessary, relating to infringement of patent rights. William Henry Fox Talbot announces that John Hind has discovered another asteroid [Euterpe]. 13 November 1853