Which two Presidents were sworn in by a previous President?

Herbert Hoover and Calvin Coolidge were sworn in by William Taft. Coolidge in 1925 and Hoover in 1929. Taft was the Chief Justice in 1923 when Warren Harding died in office but Calvin Coolidge was at his father's home at the time. Coolidge's father was a notary public and therefore swore his son into office to finish Harding's term. Taft swore him in for the second term.