Despite a running time that exceeds 4 1/2 hours, there is rarely a slack moment in "Bonaparte and the Revolution," which plays through Sunday in the admirable French revival series beginning now at the Key in Georgetown. By the time the movie shifts down from a boldly dramatic, tempestuous high gear to pick up the courtship of Napoleon and Josephine in a subdued humorous style, you've been riding a vintage cinematic whirlwind for three hours, swept along by the great Abel Gance's dynamic re-creation of a tumultuous historical period.

"Bonaparte and the Revolution" is an awesome and ultimately exhausting experience, but confirmed movie freaks owe it to themselves to step into this uniquely thrilling time machine at least once in their lives. It preserves as much of the spectacle and spirit of Gance's epic filmmaking style as one is ever likely to see.

Completed in 1971, "Bonaparte and the Revolution" is a revised and reconstructed version of one of the monumental achievements of the silent screen, "Napoleon vu par Abel Gance," which was begun in 1925 and first shown -- in what must have been one of the most sensational debuts in movie history -- at the Paris Opera on Apr. 7, 1927. Arthur Honnegar conducted the orchestra in a specially arranged score on that occasion, and the stage held a massive screen to accommodate the panoramic and triptych compositions Gance achieved with his three-camera Polyvision process, which anticipated both Cinerama and Cinema-Scope by three decades.

In 1934 Gance prepared a condensed sound version of the film that added a music track, sound effects and post-synchronized dialogue, spoken where practical by the original cast members. Fortunately for the history of the theater, Antonin Artaud, who played Marat, was still available to dub himself. The addition of his harsh, searing voice enhances the terrifying brilliance of his image.

Artaud projects a crazed intensity recalled now by Robert De Niro in his performances for Martin Scorsese in "Mean Streets" and "Taxi Driver." The sight and sound of Artaud on a line like, "If there's no wine, drink blood!" is not easily shaken off.

Typically ahead of his time when it came to major technical innovations, Gance recorded the sound version in stereo. He had also shot one reel of "Napoleon" in a new color process and a second in a 3-D process. He abandoned the 3-D as perhaps too distracting, even in the context of a prodigiously inventive pictorial feast. A few moments of the color remain in "Bonaparte and the Revolution," and these flashes of gold and blue tinting look wonderful.

Gance shot several inserts and brief connecting scenes for "Bonaparte" and appears himself in a prologue. He was 82 at the time and will celebrate his 90th birthday on Oct. 25 of this year. In the course of the original footage he appears giving an impressive account of himself in the role of Saint-Just.

Claude Lelouch, making good use of some of the profits from "A Man and a Woman," put up most of the money for "Bonaparte and the Revolution." Although Gance's reconstruction frequently involves stitching together sequences obviously shot years apart and then reinforcing the stitchery with narration, the material maintains a dynamic expository rhythm and surprising dramatic integrity. Even when he was postsynching, Gance was experimenting. Instead of seeking precise matches with the lip movements in the silent version, he used the soundtrack as a fresh dynamic resource, blending the speaking voices and images in ways that overlap vividly and coherently but not always precisely.

The movie is also unified emotionally by Gance's indomitable fervor and heroic sense of vocation. "The cinema is a flame in the shadows fed by enthusiasm," he once declared, and it's peculiarly moving to hear him reiterate this idea at the beginning of "Bonaparte": "Enthusiasm is the great conductor of life. Luckily, I still have mine. Help me preserve it!"

Gance's movie, in the tradition of Griffith's epics, is one of those pioneering silent classics that threaten to burst the bounds of the medium. It was revealing -- and not all that immodest -- for Gance to place his name next to Napoleon's in the original title. His "Napoleon" appears to have been an ecstatic spectacle, the product of a creative artist intoxicated with the possibilities of his medium and eager to enlarge those possibilities.

The movie was at once his greatest triumph and his professional undoing. It was shown in its full panoramic magnificence in only a few European cities. After purchasing American rights for the considerable sum (at that time) of $400,000, MGM cut "Napoleon" to 80 minutes, in which form it infuriated exhibitors and perplexed audiences. Gance is convinced MGM dumped the film out of fear of whetting a mass public's appetite for Polyvision, especially when the industry faced the need to convert to talkies.

Gance's ambitions were bound to spook movie financiers and executives. The colossal "Napoleon" represented only a fragment of his original conception, a six-film cycle covering Napoleon's life from beginning to end. Finally, Gance had to be content covering the boyhood (almost totally eliminated from "Bonaparte and the Revoluton" unfortunately), the early years of the Revolution which led to Napoleon's emergence as a military leader and the beginning of the campaign in Italy. Watching his rousing depiction of these events, you're reminded of Woodrow Wilson's comment about "The Birth of a Nation": "It's like writing history with lightning."

The ordinary 35mm dimension of "Bonaparte and the Revolution" cannot reproduce the scenic effect Gance's most ambitious sequences were designed to produce. At best one can infer the intended wide-angle spectacle from the spacious locations and elongated, scrunched-up bodies. On the other hand, the reconstruction preserves the heady excitement of his rapid cutting, multiple images and mobile camerawork.