The "History of Clogging" program devised by the Fiddle Puppets, a troupe of step dancers based in the Annapolis area, has a wonderful sense of alchemy about it. Instruction and enlightenment are somehow transmuted into scintillating performance without the least whiff of didacticism. The group's techniques ought to be patented -- they have discovered how to remove all the stuffiness from the "lecture-demonstration" format.

To begin with, the ratio of demonstration to lecture is about ten to one. Nevertheless, the Fiddle Puppets program, as seen in the Smithsonian's free "Saturday Live" series at the Hall of Musical Instruments this past weekend, managed to cover an astonishing amount of ground in less than an hour. With the exceptionally able and spirited help of Alexandria fiddler Steve Hickman, the dancers explained and illustrated clog dancing in its various forms; explored its Old World roots and its American extensions and offshoots; involved the audience in a body-slapping "ham bone" session and in rudimentary step dance routines; and embedded all this in a fast-paced, witty and exuberant exhibition of their own remarkable clogging skills.

The four young dancers -- Rodney Sutton, Amy Sarli, Eileen Carson and Eddie Carson -- banded together as the Fiddle Puppets in 1979, and have been seen in folk festivals throughout the United States and Canada, as well as locally at Wolf Trap and the National Theatre. They are no mere Sunday dilettantes, but accomplished professionals who tour, teach and perform full time. All the same, they never let their expertise get in the way of their sense of fun.

Still, the program had some serious points to make about the evolution of an American folk art. The clog dancing that emerged from southern Appalachia can trace its ancestry to step-dance forms brought to these shores by Irish, Welsh, Scottish and English immigrants. Within the American "melting pot," these idioms were not only blended, but also profoundly influenced by the dances of native Americans and transplanted Africans -- tap dance was one of the unique byproducts.

The Fiddle Puppets gave life to this history by showing the dances -- a soft-shoe Irish reel for two women with linked arms and pulled-up bodies; an English reel performed in special, laced clog shoes with upturned toes and thick wooden soles; the contrasting American clog, with its looser upper body and arms, less strict form and more improvisatory rhythm; a South African Boot Dance, with its emphasis on dropped heels; and a typically syncopated, free-swinging tap dance performed by fleet-footed Sarli, who has been coached by Philadelphia master hoofer La Vaughn Robinson. Winding up the afternoon was a kitchen-sink finale, a clog embellished by spins, brushes, kicks, and whirling forelegs, all at a breakneck tempo. In short, a first-rate show.