John Tyndall 1820-1893 British physicist, a colleague of Faraday who investigated the transmission and absorption of radiant beat. A.L.S. 1p. 8vo. on Royal Institute embossed letterhead, [England], June 14, 1884 Tyndall thanks a lady for her concern upon the death of a relative of his wife: "...On the evening of thefatal day my wife started for Heidelburg, so as to lessen by her presence the shock to her suffering mother...." Fine.