James B. Downton, 78, who taught Latin and Greek at Bethesda-Chevy Chase High School and later at St. John's College High School in Washington, died of congestive heart failure Jan. 3, 1995 at his home in Rockville.

From 1954 to 1979, Mr. Downton was on the faculty at Bethesda-Chevy Chase, where he also sponsored the Key Club and was head of the foreign languages department. He taught at St. John's College High School from 1979 to 1985.

Mr. Downton was born in Pittsburgh. He graduated from the University of Buffalo and received a master's degree in Greek from Duke University and a master's degree in linguistics from Harvard University. He also did postgraduate study at the University of Chicago.

During World War II, he served in the Army in Europe.

He was a member of the American Legion, the Montgomery County Education Association and the Maryland State Teachers Association.

He was a volunteer tutor with the Literacy Council.

Survivors include his wife of 38 years, Islah M. Downton of Rockville.