HAY, John, an American author, born in Salem, Ill., Oct. 8, 1839. He was educated at Brown university, studied law at Springfield, Ill., and had just been admitted to the bar when he received the appointment of private secretary to President Lincoln (1861). He remained with the president almost constantly until his assassination in 1865, but served as a staff officer for several months in the field during the civil war. In 1865 he was appointed secretary of legation at Paris, where he remained till 1867, when he was transferred to Vienna. Here he was for some time chargé d'affaires; and in 1868 he was again transferred to Madrid as secretary. In 1870 he returned to America, and became attached to the staff of the “New York Tribune.” He has written “Pike County Ballads” and “Castilian Days,” both published at Boston in 1871.