ON HIS TRIP TO AMERICA in 1832, German Prince Maximilian observed, "The beginning of settlement is always the destruction of everything."

"Views of a Vanishing Frontier" at the Natural History Museum shows how right he was.

An enthusiastic naturalist, Maximilian hired Swiss artist-illustrator Karl Bodmer to travel with him to record the landscapes, the wildlife and, especially, the "many tribes of the aborigines." They spent 13 months traveling the Upper Missouri.

More than 120 watercolors by Bodmer make up this travelogue, along with the prince's observations and more than 50 Indian artifacts.

Some would call the prince eccentric. Maximilian sent out his valet (handily, also a hunter and taxidermist) for specimens. But even when it became necessary to use the fauna as food, Maximilian insisted on meag a carcass before reluctantly surrendering it to the cook. Maximilian was also known to use a cask of good brandy to preserve snakes.

His rabid enthusiasm was not shared by the crew of the little keelboat, aptly named "Flora," that took them the last 500 miles up the Missouri to Fort McKenzie. For lack of space, specimens had to be stored on deck, and likely as not the crew members would toss the animal skins and skulls overboard during the night.

The prince and the painter: The prince kept a detailed journal concerning wildlife, Indians, weather and everything. He later published it along with prints based on Bodmer's studies. But it was the painter who captured the story best. His work ranges from watercolors of clearly dead lynx and deer, to fabulous landscapes, though not so fabulous that we can't believe they existed, and tribal chiefs.

During that last 500 miles of wilderness, heading into Montana and Blackfoot country, Bodner recorded rock formations -- majestic escarpments, where the only human figures were crew members towing the "Flora" upstream.

The landscapes are certainly lovely in their way -- and accuracy doesn't prevent Bodmer from conveying mood. But the Indian portraits are the most vital and exciting of his work.

Bodmer's trip with Maximilian took place only a year after another more famous Indian portraitist, George Catlin, journeyed up the Missouri. The catalogue for this show suggests that Catlin's paintings were impressionistic, while Bodmer sought to make his pictures as detailed as the prince's observations.

Bodmer painted the prognathous Blackfoot named Distant Bear, with cheeks and forehead a lurid green, who believed his portrait protected him from bullets in battle -- unlike many other Indians who felt their portraits weakened them.

There was the Mandan chief Mato-Tope, or Four Bears, the self-promoter, who depicted his warrior feats on his robe and in his body paint. He wore a wooden knife in his hair, symbolizing one of the five chiefs he reportedly killed. Mato-Tope visited the explorers often at Fort Clark, and rarely wore the same outfit twice.

In spending an entire winter at Fort Clark (in what's now North Dakota), Maximilian and Bodmer moved closer to sociological observation: Bodmer depicted games and homelife. As Maximilian's sign language improved, they began to form friendships among the Indians.

For the explorers, the journey ended well. The stars had been right for it. A few years before, the Blackfeet were hostile to whites. A few years later, the Mandan tribe was decimated by smallpox brought upriver by a fur company steamboat.

VIEWS OF A VANISHING FRONTIER -- At the Museum of Natural History through March 31.