August 14, 1988

LEAD: THE Republicans are back in the South again, which is almost getting to be a habit. The national party that was founded in 1856 to fight slavery did not hold a Presidential nominating convention in a city of the Old Confederacy until 112 years later, when its delegates gathered in Miami Beach in 1968.

LEAD: WHEN Oscar Scherer was being considered in the spring for principal of the Blue Mountain Middle School in the Hendrick Hudson School District in Montrose, he first was interviewed by a committee that included several teachers from the school.

LEAD: Last Thursday, Cray Research Inc. announced the first sale of its new supercomputer, the Cray 3, to the Pittsburgh Supercomputing Center, which gets much of its financing from the National Science Foundation. The new machine, which will perform 16 billion calculations a second, will not be delivered until 1990.

LEAD: Tomorrow morning in the High Bridge section of the Bronx, worlds away from bedroom views of the Statue of Liberty, work will begin on the first city-owned shells to be renovated using surplus Battery Park City revenues.

LEAD: In ''Cocktail,'' unquestionably the party-hearty movie of the year, the story's bartender hero, Brian Flanagan (Tom Cruise), recites this poem: