On April 15, 1848, in the quiet of the night, 77 black slaves fled from the homes of some of Washington's wealthiest and most prominent families and slipped onto a small schooner named the Pearl, hoping to sail to freedom.

They left from the Washington channel of the Potomac River at midnight, but it was early morning before their ship caught any wind. Then the 38 men, 26 women and 13 children got only 140 miles away before the weather forced them to anchor. It was there that a steamer with many of the slaves' owners aboard captured them.

Josephine F. Pacheco, a history professor at George Mason University, recounted in detail this little-known incident in Washington history, called "the Pearl affair," at the Martin Luther King Library as part of the 13th Annual Conference on Washington, D.C., Historical Studies. About 30 people attended the lecture, which came during Black History Month.

"The widespread news of the Pearl affair shook the nation and became a major incident in the history of antislavery in the United States," said Pacheco, who said she hopes to write a book about the failed escape.

The incident occurred 13 years before the start of the Civil War. James K. Polk was president and Daniel Webster was in the Senate. Washington was a small city of 52,000 and very Southern. The city's population included 38,000 whites, 10,000 free blacks and 4,000 slaves.

The escape plan was conceived by Daniel Bell, a freedman who feared that his wife and eight children, who were slaves, might be sold. Bell had gone to Philadelphia to try to raise enough money to buy his family's freedom, but his effort was unsuccessful.

When that failed, Bell approached Daniel Drayton, a white sailor who had helped another slave escape from the South, and asked him to take charge of a ship that would sneak out of the District and sail to Philadelphia -- and freedom -- with Bell and his family aboard as stowaways.

Drayton, who was not a known abolitionist, risked his life to help the slaves. He arrived in the District worried about how to contact the Bell family, but according to Pacheco, "It was soon apparent that the entire slave community knew of the plan to escape.

"Soon the hold of the Pearl was full," said Pacheco. "Unfortunately, there was a dead calm. The tide was coming in, and not until almost daybreak did the wind pick up enough for the little vessel to set off down the river. Drayton and his passengers must have been frantic at the delay."

The Pearl picked up wind and traveled 140 miles south without incident, reaching the Chesapeake Bay. As they approached the mouth of the Potomac, fierce winds prevented the ship from sailing north.

With nothing else to do but wait for a break in the storm, Drayton and the 77 fugitives anchored in Cornfield Harbor, just south of Point Lookout at the southern tip of St. Mary's County in Maryland. Exhausted from the journey, Drayton and the fugitives fell asleep.

Included in the group was "a female slave belonging to Dolley Madison, the widow of a former president. A man who worked at the National Hotel, at the corner of Pennsylvania Avenue and Sixth Street NW, joined the group, leaving all the boots unblacked," Pacheco said.

Many of the slave owners were furious when they awakened on the morning of April 16 and realized they had no breakfast, no shined boots and no saddled horses -- all of which was slaves' work. In a short time it became clear that the slaves had fled.

City slaves were allowed to move about more freely than their rural counterparts. One owner marveled at the escape, saying that he had not only raised his two slaves in his house, but in an attempt to maintain a family grouping had purchased their mother as well. The widespread belief among the owners was that the slaves had been enticed to follow an abolitionist."The sounds of loud shouts and trampling of many feet overhead must have been the sounds of doom . . . " -- Historian Josephine F. Pacheco

The owners decided to form a posse and pursue their property on horseback to Pennsylvania, the closest nonslave state to Washington. But after questioning both freedmen and slaves, they learned the truth from a former slave named Judson Diggs.

Diggs, according to some accounts, had two reasons to betray the fugitives. Aboard the Pearl were six members of the Edmonson family, including two sisters, Emily and Mary.

Diggs had tried to court one of the women and had been rejected by her.

In addition, Diggs had driven some of the fugitives to the ship and was not paid.

Once the slave owners learned of the escape, they boarded a steamer named the Salem and set out to capture their property.

It was early on April 17 when the Salem pulled alongside the Pearl, catching the slaves by surprise.

"The sounds of loud shouts and trampling of many feet overhead must have been the sounds of doom to both black and white," said Pacheco. "They heard the hatch being lifted and a voice crying out, 'Niggers, by God!' "

Drayton and two white passengers were chained and brought aboard the Salem. The slaves were left on the Pearl, which was towed back to Washington.

An angry mob had gathered on Pennsylvania Avenue to greet Drayton and the slaves as they were marched -- in chains -- to the three-story brick jail at Fourth and G Streets NW.

Drayton was tried and imprisoned. He was freed four years later by a presidential pardon. The fugitives also were jailed and later sold to slave dealers from Baltimore, Annapolis, Richmond and as far away as New Orleans and Georgia.

The Edmonson sisters, Emily and Mary, were sold to an Alexandria slave trading firm for $750 each. Their father, with the help of New York clergymen, raised the $2,250 needed to buy their freedom.

Harriet Beecher Stowe heard of the sisters and later paid for both of them to attend Oberlin College. Emily Edmonson later assisted Myrtilla Minor in establishing the District's first high school for black children, which was located between 19th and 20th streets and M and O NW.