"Why on earth did they do that?" exclaimed the old collector.
"As an offering to the Spirit of the Lake," returned the professor. "The Spaniards, when they heard the story, named the lake, Eldorado—The Lake of the Golden Man. As the centuries went by, the location was lost—until I found it again."
There was a long pause, which was broken at last by the lumber-king.
"Have you any proof that this story of yours is true?" he inquired sarcastically.
For answer, the scientist fished a dingy bag from his pocket and shook out on the table a circlet of soft, pale gold in which gleamed three green stones.
"I found this ten feet from the shore," he said simply.
The lumber-king gasped as he studied the stones with an expert eye.
"Professor Ditson," he admitted at last, "you're all right and I'm all wrong. That's South American gold. I know it by the color. African gold is the deepest, and South American the palest. Those stones are emeralds," he went on; "flawed ones, to be sure, but of the right color. The common emerald from the Ural Mountains is grass-green," lectured Mr. Donegan, fairly started on his hobby. "A few emeralds are gray-green. Those come from the old mines of the Pharaohs along the coast of the Red Sea. They are found on mummies and in the ruins of Pompeii and along the beach in front of Alexandria, where treasure-ships have been wrecked."
Professor Ditson yawned rudely.
"Once in a blue moon," went on the old collector, earnestly, "a real spring-green emerald with a velvety luster, like these stones, turns up. We call 'em 'treasure emeralds,'" he continued, while Professor Ditson shifted uneasily in his chair. "Most of them are in Spanish collections, and they are supposed to be part of the loot that Cortez and Pizarro brought back to Spain when they conquered Mexico and Peru. How large did these old Peruvian emeralds run?" he inquired suddenly.