Columbus was first, Pan American's former chairman Juan Trippe second, and O. Roy Chalk likes to say he was third to discover the Caribbean.

Chalk still owns an airline that flies there, once owned a newspaper that wrote about it, a radio station that talked about it and even a railroad that ran up and down its spinal column, Central America. ("I know El Salvador like nobody in the State Department knows it," he says.)

Last night, Chalk, who hasn't been seen much lately around town, talked about his Caribbean connections. Still chairman of D.C. Transit System Inc., he hosted a $500-a-person fund-raiser at his Falls Church home for the College of the Virgin Islands. He was one of those helping Ralph M. Paiewonsky, governor of the Virgin Islands at the time, found the college in 1961.

The way Chalk and others at his party see it, the college can have considerable impact on that part of the world.

"There's a little fellow called Castro who offers education to people in the Caribbean Islands. Well, we do too," said Chalk.

The Caribbean is on a lot of people's minds these days. They're waiting to hear what U.S. investment incentives President Reagan will propose in non-U.S. islands, when he delivers his Caribbean basin statement soon.

Recently, the House passed a bill authorizing $150,000 to plan an eastern Caribbean center for educational, cultural, technical and scientific interchange at the school. The center would improve upon the school's existing ability to provide U.S. assistance to the strategic region.

"It's for an interchange of ideas because we have as much to learn as we have to offer," said the college's president, Arthur A. Richards. "We believe we ought to be the window of the United States in the Caribbean."

Stuart Eizenstat, former chief domestic adviser to President Carter, last night called the college the "most important institution in the Virgin Islands in terms of building a middle class. No country has been able to sustain a democracy without a middle class and what this college has been able to do is produce the teachers, the accountants, the technocrats that make up the middle class."

Like Eizenstat, a member of the college's board of overseers, actress Maureen O'Hara Blair said the college is attracting students from throughout the Caribbean.

"Hopefully, we can educate them in democracy so they can go back to their small countries with that."

It was a common theme stated and restated by the nearly 100 guests, many of whom flew from the Virgin Islands especially to attend last night's dinner. Paiewonsky said American leadership in the area is there for the taking. Many cultures are so intertwined with the American presence in the Virgin Islands now that one Caribbean prime minister once chided him about it. "He said his people didn't want to die and go to heaven, they wanted to die and go to St. Thomas."