At a bustling St. Louis fair in 1904, a refined Minnesota music teacher from Red Wing in her mid-30s leaned in close to listen to an American Indian legend humming a tune.

Geronimo, the Apache warrior, was 75 and signing autographs — carefully printing his name on cards he sold to passersby at the Louisiana Purchase Exposition.

"I stood behind him," Frances Densmore later recalled, "and noted down a melody that he hummed."

She was just getting started. Densmore spent the next 50 years on a quest to preserve Indian music — lugging bulky recording equipment, notebooks and tripod cameras to remote Indian villages from Minnesota's North Woods to Arizona's painted desert.

When she was done with her last recordings, capturing Seminole songs in the Florida Everglades in 1954 at age 87, Densmore had collected more than 2,500 Indian songs on wax cylinders for the Smithsonian Institution's Bureau of American Ethnology. Updated versions of her fieldwork now live on in the Library of Congress.

In 1905, a year after crossing paths with Geronimo, Densmore found herself among Ojibwe at White Earth in northwestern Minnesota. She noted the excellent singers, the picturesque costumes and the feverish dancing on the green, mid-June prairie.

"Hour after hour I sat beside the dance circle, becoming more and more impressed with the idea that I must record Chippewa songs," she later wrote.

By 1907, using a primitive Edison home phonograph machine borrowed from a Detroit Lakes music shop, Densmore recorded music sung by an Ojibwe man named Big Bear and his friends. Soon she was visiting the Leech Lake Reservation village of Onigum — one of many places she traipsed that seldom saw unaccompanied white women.

Her visit to Leech Lake came at what she called "an opportune time." That is, if you're a music researcher — not the chief of the band.

"Flat Mouth lay dying … and I was the only white person present," she said. "The Indians knew I was there but made no objections, and I heard songs that were sung only on such an occasion."

Densmore's love of music started early. She grew up in a song-filled house in Red Wing. Her father, Benjamin, had led black troops in the Civil War and worked as a civil engineer and foundry owner. Her mother, Sarah, was both disciplined and open-minded.

From her childhood home on the Mississippi River 50 miles southeast of St. Paul, Densmore could hear the rhythmic chanting of Dakota Indians camping on a nearby island.

"We could hear the throb of the drum when they were dancing and sometimes we could see the flickering light of their campfire," she wrote. "If my mother had told me that Indians were savages, I might have been afraid to go to sleep. Instead I was told they were people with different customs from our own and there was no fear in my mind. I fell asleep night after night to the throb of the Indian drum."

As a young woman, Densmore studied piano, organ and harmony at Oberlin College in Ohio, continuing those studies in New York and Boston.

"Years passed and I grew up in the white man's music becoming a piano teacher and organist," she wrote. "But there remained a wonder about the Indians dancing to the throb of the drum across the water."

In 1893, at the Columbian Exposition in Chicago, "I heard Indians sing, saw them dance and heard them yell and was scared almost to death," she wrote.

During the ensuing decades, her fears eased and she became close friends with many Indian leaders. But she always kept a prim, professional distance — staying in white government bureaucrats' homes near distant reservations.

While early American anthropologists tried to embed themselves with the targets of the research, Densmore insisted she never obtained material "by pretending to be one of them and eating out of the same dishes. I have seen people who use this technique and did not find out very much. There is no use trying to be a social climber among Indians."

Densmore was driven by the notion that Indians were vanishing amid white immigrants' progress and that their music would soon disappear. She cobbled together funding from the Smithsonian and other benefactors, often traveling with her sister, Margaret, by train, wagon and canoe.

Over the years, her romantic idealization of Indians turned somewhat bitter, according to St. Paul's Stephen D. Smith, an editor for American RadioWorks, who spent a year researching Densmore in the 1990s for Minnesota Public Radio (see his report at: http://tinyurl.com/FrancesDensmore).

As she lectured early in her career, Densmore described a typical Indian leader as a man who "holds his head high and walks with the old dignity, but the barbed arrow is in his heart. The white man has no time to sit by the fire, smoke the long pipe and exchange grave compliments with his dark brother."

When Indians failed to dissolve into the American melting pot as she predicted, Densmore's sympathy hardened, Smith said. During her decades of research, she said: "I never let them criticize the government nor the white race, nor come across with any sob-stuff about the way they had been treated, as a race."

She had spent her last 15 years retyping notes, meticulously documenting her research for the historical record and making sure everything was tucked away in the Library of Congress.

When Densmore died of pneumonia in Red Wing two weeks after turning 90 in 1957, her will directed that all letters, notebooks and manuscripts left in her desk be burned. Her work was complete, and she didn't want anyone analyzing her private chronicles after her death.

Curt Brown's tales about Minnesota's history appear each Sunday. Readers can send him ideas and suggestions at mnhistory@startribune.com