“This explains something that has been puzzling me,” exclaimed Mr. Chadwick, as they made this discovery. “It’s plain enough now that the crew knew there was no land to be expected in this part of the ocean, and when we struck they at once assumed that we had encountered some uncharted rock and so took to the boats.”

This explanation threw some light on the desertion of the yacht by means of the boats, for it had occurred to all of them that if the yacht had struck on the coast of the mainland there would not have been such a precipitate rush to leave her.

“My idea is to look in the pilot house and overhaul the charts,” said Captain Sprowl, after some discussion had ensued as to the best course to follow. “Our course must be marked till noon yesterday, anyhow, and we can find out about where we are.”

Whatever may have been Medway’s other faults, he could not have been called a slovenly navigator. The course of the yacht was plainly marked up till eight bells of the day preceding, and showed that they were then off the coast of Brazil. Captain Sprowl “overhauled” the pilot house some more, and at noon made an observation with a sextant he had unearthed. After making some calculations, the results of which were awaited with an eagerness that may be imagined, he announced that the position of the yacht was about one hundred and fifty miles from shore, and a little to the south of the mouth of the Amazon River.

“Himmel,” cried Professor Von Dinkelspeil, his frog-like eyes gleaming through a huge pair of horn-rimmed spectacles, “dey vos bringing us rightd vere I vanted to go!”

“Yes,” said Mr. Chadwick, “the professor’s destination was the Amazon River, but I must await his leave before telling you what his exact object was in coming to this part of the world.”

“Treasure, wasn’t it?” hazarded Dick Donovan.

“I’m afraid you have a reporter’s love of the picturesque,” smiled Mr. Chadwick. “Yet I suppose it was treasure of a kind; but not of the sort that the misguided crew imagined.”

“It’s this pesky island that puzzles me,” grunted Captain Sprowl, bending over the chart and knitting his brows. “There isn’t anything like it marked here, and this chart is based on the very latest survey made by the British cruiser, Charybdis.”

“Maybe it was too small to mark down,” suggested Jack.