Copy letter, from Sir John Herschel to Richard Anthony Proctor, 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. Discusses Olbers's Paradox, raises objections to Richard Anthony Proctor's argument for the existence of dark celestial matter, and points out problems in Richard Anthony Proctor's method of measuring stellar diameters. 20 August 1869