“Can’t you tell me why he is following you?”

“No, sir.”

“Then,” Clay declared, “you go back to your bunk. You’re going to remain with us, and if trouble comes we’ll fight it out together.”

“But you don’t know,” began the other, but Clay hustled him away!

Then he sat for a long time in deep thought on the dark deck.

CHAPTER VIII.—AN ADDITION TO THE PARTY

The river is wide at Para, and there are always dozens of steamers and trading vessels anchored off the city. This night was no exception. There was a little group of vessels lying within hailing distance of the motor boat. The one nearest, perhaps, was the steamer which Frank had called the Señorita, not a large boat, but one having the appearance of great speed.

There was little stir of life on the river, and Clay watched light after light go out in the nearby craft with a sensation of loneliness. Now and then, it is true, he could hear a voice coming over the water, but usually the words spoken were in an unfamiliar tongue. The air was dry and warm.

The moon, passing farther to the west, had encountered a bank of clouds, and was visible only a part of the time. In these darker intervals, whenever the listening boy heard the rattling of an oar it seemed to him that the boat in which it swung was stealthily approaching the Rambler with some sinister purpose in the hearts of those within her.

He knew that Frank was not asleep, for he could hear him tumbling about in his bunk, and more than once he started up with the purpose of calling to the lad and having the truth of the danger which hung over him clearly defined, but each time he sat down again, reluctant to press him on so delicate a subject. His idea was that, at sometime during the night, something would occur which might give him an inkling of the threatened danger.