In the 18th century, shipping was everything. It moved people, goods and mail across the ocean and along the coasts, doing the work of modern-day planes, trains and trucks.

Thus, the amazingly accurate chart that Benjamin Franklin sketched out with his whaler cousin, Timothy Folger, complete with instructions on how to exploit and avoid the Gulf Stream, was a treasure map that logically should have been a hot item.

Yet, not long after the chart was published in 1769, it disappeared.

Two centuries later, the mystery of the missing chart piqued the interest of a young oceanographer named Philip Richardson.

Richardson received his doctorate from the University of Rhode Island in 1974 and took a job at the Woods Hole Oceanographic Institution. There, Fritz Fuglister, one of the institution's legendary Gulf Stream experts, fired Richardson's imagination with tales of the superiority of the 1769 map.

Later versions of the chart were widely circulated, but they contained errors, and, as it turned out, were inferior to first-edition copies of the original.

In 1979, while on sabbatical in France, Richardson decided to dive into the rare-documents section of the Bibliothèque Nationale in Paris. He figured that if anyone saved copies of Franklin's chart, it would be the French.

"I knew the French loved him," Richardson said, "even more than Jerry Lewis."

The French certainly would have valued the chart more than the British packet-ship captains for whom it was drawn and to whom it was distributed.

"The British captains slighted the chart, probably because they did not appreciate the implication that American fishermen knew more about ocean currents than the British," Franklin recalled Folger telling him.

It was just as well, as tensions built between the colonies and the mother country. Neither Franklin nor colonial naval strategists would have wanted to share such valuable information about the volatile North Atlantic with the enemy.

When Richardson went looking for the chart 200 years later, he naturally pored through books looking for references to the "Gulf Stream." But at the time that Franklin and Folger drew the chart, the term wasn't in wide circulation.

Richardson then looked under the engraving company, Mount & Page. Mining the stacks, he came up with two original copies of what unmistakably was the 1769 Mount & Page chart, and a third one in French.

The finding was a sensation. The New York Times ran a front-page story about it. Richardson, who had built a quiet reputation in the oceanographic community as an expert in Gulf Stream eddies, suddenly was a celebrity.

"It's the first time I had done anything that anyone publicly noted," he said.

He recalled that, afterward, his boss at Woods Hole would always introduce him as the man who found Franklin's chart. "He never said I was a great researcher."