A slyly poignant show

Eccentrics are sensitively handled in the engagingly entertaining and subtly educational film Vernon, Florida (PBS, Wednesday, Aug. 18, 9-10 p.m., check local listings; in New York, Thursday, Aug. 19, 10-11 p.m.). The show is as slyly poignant as a Chaplin film.

The roots of individual eccentricity are often a major sociological and philosophical clue to local mores and even wider societal patterns. Errol Morris -- whose earlier study of pet cemeteries, ''Gates of Heaven,'' despite its seeming superficiality, was a revealing study of one aspect of our society -- has done it again in this study of a group of small-town individualists who reveal their insights in their own mundane words.

Morris achieves a kind of human counterpoint as he intercuts interviews with a wild-turkey hunter, a service station owner, a fundamentalist minister, a highway patrolman, etc. Then there is the couple who visited White Sands (N.M.) and brought back a jar of sand which they insist is growing inside the jar.

''Vernon'' is filled with populist wisdom and old wives' tales, all spoken and recorded in dead earnest. The voice of the interviewer is never heard as the film proceeds to listen intently like a wise child, eyes open wide, as people spin their tall tales with innocent good humor. The film is like a series of Charles Kuralt ''On the Road'' programs, although it lacks the on-camera compassion of Kuralt. It makes up for that lack with a certain universality, however, which results from the viewer's being forced to feel he is functioning as a silent participant in an actual conversation. What may feel like boredom at moments proves to be slow-dawning realization in the end.

''Vernon'' is another in the ''Non Fiction Television'' series administered by the Television Laboratory at WNET, New York. This unforgettable film is a unique learning and viewing experience.