Copy of letter, from Sir John Herschel to [William Radcliffe Birt], dated at Collingwood Copy of letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. Received copies of barometer observations. Searching for original data (lists stations) that John Frederick William Herschel sent to William Radcliffe Birt. Invites additions to John Frederick William Herschel's report. Please send account of expenses. 20 July 1843