"Treasure Planet" answers a question that to my knowledge has never been asked before, possibly because no one cared: What kind of a 30th century would the 18th century make?

The issue isn't likely to be on anyone's Must-Figure-Out-Before-Dinner list, but the answer, contained in the new, lovely Disney animated feature, is nevertheless quite interesting: The 18th century makes a splendid 30th century.

That's the film's continual source of delight. The directors, Ron Clements and John Musker, and their staff of 34,598 technicians use "Treasure Island," the venerable boys' maritime adventure by Robert Louis Stevenson, as the template for a projection into some far-distant future when ships still sail and pirates still close and grapple and things still burn and sink.

Like the four-masters of yore, plying the majestic blue seas of the Pacific laden with cargo or hungering for plunder, these four-masters ply a blue sea of stars to exotic atolls hanging in space. The conceit, which works surprisingly well, is based on solar energy, so that one doesn't put nine sheets to the wind but nine sheets to the light particles and, thus filled, the solar sails pull the stately craft through the ether. They solve the air problem simply by ignoring it.

It's all quite vividly imagined, down to the tiniest details. The camera (or -- excuse me? -- whatever it is, as they don't use cameras anymore, do they?) floats upward to a crescent moon above the surface of Jim Hawkins's home planet, only to find it's a crescent all right, and also a moon, but artificial: a curvilinear spaceport whose design imperatives hail from the works of Hogarth, not Lucas. It's full of dense alleyways and crooked, raggedy little houses, and the great vessels lay moored at a dock town as hustling and bustling as any in the oeuvre of Errol Flynn. What, no Olivia de Havilland?

Well, yes, there is an Olivia de Havilland, except she's, er, a cat -- the sexy Captain Amelia, as purred to life by Emma Thompson. That's another conceit, and one that is borrowed from Lucas's "Star Wars": that this 18th-century future is populated not merely with human beings but also with creatures evolved from house pets, as well as all manner of Canteena-style weirdos, none of whom, of course, dress in spandex and powder-blue space cadet unis, but in homespun linen, thigh-high boots and broad piratey caps, the swirling, caparisoned excesses of 18th-century fashion. What a mix! It shouldn't work, but it does.

The story is purloined neatly from Stevenson and will be more or less familiar to all who've encountered that Scottish lad's spinnings over the years. The key dynamic -- surprisingly modern, given that Stevenson was writing in the 1880s -- is the ambiguous relationship between the adventurous young Jim (voiced by Joseph Gordon-Levitt) and Long John Silver (Brian Murray), who, this time through, is a cyborg, with gizmos for eyes and an Eddie Scissorhands right paw. But Silver is still the ship's cook, still a secret plotter against the ship's captain and first mate. He knows that young Jim has come into possession of a certain map to a certain planet some months' solar-sail away, and with his hearties (all aboard as ship's crew) Silver plans to mutiny and take the planet's legendary treasure for himself.

The Jim-John thing is a great relationship, because it gets so vividly at the tides of emotion that spew and fume in the straits between father and son, or young men and older men. The father loves the son, but he also hates him. He wants him to do well, but he also doesn't want to be defeated by him. He takes pride in his courage and spunk and will defend him to the death -- and then will try to kill him to advance his own ends.

Stevenson, of course, was no stranger to the duality in man, as he made clear in "Dr. Jekyll and Mr. Hyde." That duality runs through this tortured relationship as well, and if Murray's giant, hobbling bloke isn't as memorable as the classic Robert Newton in Disney's first "Treasure Island" (1950), he's nevertheless a formidable being.

The Clements-Musker team is one of Disney's most successful, numbering among their hits "The Little Mermaid" and "Aladdin," as well as the lesser "Hercules." One of their strong points is speed, as lit up at key points by a star turn. Thus, as drama, this "Treasure" is fast, playful and rather shallow, but when it seems in danger of foundering, they pump it up with a brilliant vocal performance by Martin Short as "B.E.N.," who was a human being named Ben when Stevenson invented his presence on the island. Now, of course, the marooned man is a robot. But he's really not -- he's just Martin Short, and although this isn't the place for my long-planned, definitive essay "Martin Short: God or Merely Godlike?" he really takes the movie over, after the fashion of a similarly incandescent Robin Williams in "Aladdin." Clements-Musker don't allow Short to riff the way they let Williams, so the performance isn't as free-form. But it's really fabulous; Short, one of the masters of the language of showbiz irony, manages to delight kids and adults, though in different ways.

The other Clements-Musker specialty is action. "Treasure Planet" has at least three mind-blowing sequences combining various forms of animation seamlessly and creating a truly thrilling illusion of danger. Possibly they overuse flame as a menace, but in deep space, you're far more likely to burn than drown, right?

"Treasure Planet" boasts the purest of Disney raptures: It unites the generations, rather than driving them apart.

Treasure Planet (95 minutes, at area theaters) is rated PG for action scenes.

John Silver (Brian Murray) and Jim Hawkins (Joseph Gordon-Levitt) sail the cosmos looking for buried loot in Disney's futuristic take on "Treasure Island."Martin Short gives a brilliant vocal turn as B.E.N., a marooned robot who holds the key to the treasure.The setting may be outer space in the 30th century, but "Treasure Planet" faithfully maintains the dynamic between crusty John Silver and adventurous Jim Hawkins.