Copy letter, from Sir John Herschel to William Whewell, dated at Feldhausen Copy of letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. Describes in detail efforts, only partially successful, made by Thomas Maclear and John Frederick William Herschel to record tidal data at Simon's Bay and Table Bay. Gives some interpretation of the data. 4 July 1835