"Dat am ghost-island!"
"Ghost-island? Precious little ghost about that," asserted Jim confidently.
"It's an atoll, I expect," called Jack from under the awning. "Surely we can't have drifted as far north yet as the Paumotus! By my reckoning the nearest island is over a hundred miles off."
"It's a coral island—I can see the cocoanut trees," the boy sang out excitedly.
"I'm afraid Tari's right, son," said Broncho, after a long scrutiny. "It's a mirage!"
"A mirage?" exclaimed Jim incredulously, in tones of deep disappointment.
It was a wonderful sight. There lay the island, plain to see, and no one but a trained observer could have detected that it was a sham.
But Tari and Broncho were right. Many a mile had the cowpuncher ridden in chase of just such a lifelike image on the prairie without getting any nearer.
"These here mirages is just a deadfall, an' many a poor cowman has panned out through trailin' after them," observed Broncho.
"Well, the island that mirage reflects is somewhere down under the horizon," said Jack. "Just take its bearings, one of you, and we'll shape our course for it directly the wind condescends to blow."