THERE'S A WHALE of a tale to be told here, boys. Of a South Seas voyage that swung around the world. Of the six ships that sailed in the first U.S. naval expedition, and the two that came back. Of the brilliant and egocentric Lieutenant Charles Wilkes and his crew -- among them, naturalist Titian Peale and the great geologist James Dwight Dana. And of the 50,000 plants and 4,000 animals they brought back -- the stinking specimens that Wilkes forbade the scientists to take belowdecks.

At the Natural History Museum, "Magnificent Voyagers: the U.S. Exploring Expedition, 1838-1842" takes us back to the days of wooden ships and iron men, or is it the other way around? We enter through a planked passageway made to look like the lower deck of Wilkes' flagship, the Vincennes. Here we see a wooden globe with two big holes -- one in either end. From the early 19th century, the globe belonged to John Cleves Symmes, and represented his "Holes in the Poles" theory. Though not taken too seriously, his idea inspired interest in traveling to arctic climes and helped spur these ships on their way.

They sailed to Antarctica, travelled 1,500 miles along its coast to prove that it was a continent, saw French ship, did not sink same, but, diplomatic signals being twisted, did ignore same. As the trip was considered America's scientific Declaration of Independence, pride may have been involved.

A sweeping mural here depicts the two passing ships in the Antarctic terrain, which Wilkes described as "an immense city of ruined alabaster palaces . . . with long lanes . . . winding irregularly through them."

There was excitement in store in the Fiji Islands, where Wilkes' nephew was attacked and killed by natives; the company retaliated. But despite this the voyagers brought back an extraordinary ethnographic collection. Draped in yards and yards of patterned bark cloth, a Fiji chief presides over this show. Four carved Fiji figures are the oldest in any museum. And clubs, spears, slings and bows and arrows make a nice sunburst arrangement here.

Of course things were not so pristine then. The crew members were just starting to disbelieve the nasty rumors that the Fijians were cannibals, when one of their Fijian friends came aboard carrying a roasted head, plucked out an eye and popped it in his mouth. (The account is here among the many papers of the crewmen; Wilkes required them all to keep journals.)

Then there was the cruel Vendovi, who had murdered eight American seamen. To make an example of him, Wilkes had him captured in the Fiji Islands to bring him to justice in America. On the two-year return voyage, Vendovi became a popular companion. Unfortunately, he expired from tuberculosis a few hours after they landed in New York.

The "Scientifics" still had the last word, adding Vendovi's skull to their anthropological specimens. Someone had made a deathmask of him, and that's on display here.

The things the voyagers brought back were first displayed in the old Patent Office, then moved to the Natural History Museum building when it opened 75 years ago: odd plants and shells, boomerangs from Australia, fossils from Oregon Territory, a gutskin cape, big gourds and grass skirts, not to mention bamboo nose flutes from Samoa and a necklace of braided human hair, complete with fingernail.

The specimens the naval officers and scientifics brought back with them formed the core of the Smithsonian study collections. The corals are still being lent out. Charts and surveys made on the expedition were being used in World War II. A palm called "ferocious blue cycad" is said to be still growing at the U.S. Botanical Gardens.

The crew members produced 19 reports and atlases as a result of the expedition -- four years and 87,000 miles long. It was comparable to a modern-day trip to the moon. But where were the tickertape parades?

The "magnificent voyagers" came home to a series of court martials. But the only thing that stuck was a public reprimand of Wilkes. In disciplining wayward crewmembers, he had exceeded the authorized number of lashes.

MAGNIFICENT VOYAGERS: THE U.S. EXPLORING EXPEDITION, 1838-1842 -- At the Natural History Museum through November 9, 1986.

And the following satellite exhibitions:

POLAR EXPLORATION -- At the Navy Memorial Museum, Building 76, Washington Navy Yard, indefinitely.

SURVEYORS OF THE PACIFIC: CHARTING THE PACIFIC BASIN, 1768-1842 -- At the Library of Congress, Geography and Maps Reading Room, Madison Building, through April 13, 1986.

USNS KANE -- A modern naval survey ship, docked at the Franklin Street Pier, Alexandria, through Monday. Open to the public for tours Saturday from 1 to 4.