"Second, they jumped into a 'chariot' (any vehicle) where they could hide and ride away. These chariots stopped at some 'stations,'" but the word could mean any place where slaves went to be picked up.
"So Negro spirituals like 'Wade in the Water,' 'The Gospel Train' and 'Swing Low, Sweet Chariot' directly refer to the Underground Railroad."
Some songs were bold, like, "Oh, freedom, oh, freedom over me, and before I'll be a slave, I'll be buried in my grave and go home to my Lord and be free."
Strong men and women like Harriet Tubman (called the black Moses) were the conductors. The story is told that Tubman threatened to kill any slave who became frightened and wanted to turn back. She reportedly never lost any of the 300 slaves she helped lead to freedom.
"The women were very determined and resolute," Robinson said. "The men often were more afraid that they were going to get whipped and that they had to protect their families."
Negro spirituals spread across the country as slaves would leave one place and go to another, said Carl G. Harris, professor of music at Hampton University in Virginia. Harris, who did his dissertation on Negro spirituals, said there are thousands of them.
Several attempts have been made to compile them, but no one knows how many there are.
The Jubilee Singers group from Fisk University in Nashville is credited in the early 1870s with being the first choir to bring Negro spirituals to the masses. Their purpose was to raise money for their struggling school. They traveled throughout the United States and in Europe. Most had been slaves, and the story of how they were accepted is amazing, Granade said. Other black colleges followed.
Today many African-American churches sing Negro spiritual only during a black history program, Robinson said. But he said, "those are our songs" and they have meaning for today. Some traditional African-American churches still sing them, especially those with older members.
"We can relate to the music in today's context," he said. "The slaves sang, 'We're going to lay down our burdens.' We have burdens today, even though they may be different."
He includes Negro spirituals as part of the repertoire of his choirs and teaches their meanings.
"I want the choirs to know the messages and then they are more effective when they sing them and we are able to transfer the meanings to our audience."
"A lot of young African-Americans don't know their history," Baskin-Watson said. "They have not been exposed to it. I don't think the black church necessarily is the answer. A lot of them are not doing spirituals, and I don't see anything changing that."
A lot of African-American churches are more influenced by what is going on in contemporary music, Harris said.
Courses in African-American history are one way to keep knowledge of Negro spirituals alive, he said. Students develop an appreciation for them when they learn of their influence on classical music, jazz, blues and pop music, from both black and white composers.
In some public schools, they are taught as part of American folk music, not Christian music, Granade said.
He agrees that many people today can identify with Negro spirituals.
"They express emotional depth, and that carries throughout time," he said. "The slaves were looking for redemption, and we still need that today."
Some songs cross racial barriers because many Protestant hymnals contain Negro spirituals.
Now praise-and-worship songs, with the words displayed on large screens, are more popular than hymns, experts say.
But Robinson said Negro spirituals will not be lost.
"Just about everyone will have a grandma or grandpa who will sing those songs," he said.