Biographical Directory of the American Congress (1971), pp. 54, 56.
Gallatin had not been a citizen of the US for the requisite number of years at the time of his election. He first presented his credentials on 2/28/1793, but the Senate took no action. Although he was seated on 12/2/1793, the Senate reversed its mind on 2/28/1794 and declared the seat vacant.