Besides, the sand, sprinkled with mica flakes, seemed to form a sort of reflector, and the very grains could be counted glittering like luminous dust.

Benito moved on, examining and sounding the smallest cavities with his spear. He continued to advance very slowly; the communication cord was paid out, and as the pipes which served for the inlet and outlet of the air were never tightened, the pump was worked under the proper conditions.

Benito turned off so as to reach the middle of the bed of the Amazon, where there was the greatest depression. Sometimes profound obscurity thickened around him, and then he could see nothing, so feeble was the light; but this was a purely passing phenomenon, and due to the raft, which, floating above his head, intercepted the solar rays and made the night replace the day. An instant afterward the huge shadow would be dissipated, and the reflection of the sands appear again in full force.

All the time Benito was going deeper. He felt the increase of the pressure with which his body was wrapped by the liquid mass. His respiration became less easy; the retractibility of his organs no longer worked with as much ease as in the midst of an atmosphere more conveniently adapted for them. And so he found himself under the action of physiological effects to which he was unaccustomed. The rumbling grew louder in his ears, but as his thought was always lucid, as he felt that the action of his brain was quite clear--even a little more so than usual--he delayed giving the signal for return, and continued to go down deeper still.

Suddenly, in the subdued light which surrounded him, his attention was attracted by a confused mass. It seemed to take the form of a corpse, entangled beneath a clump of aquatic plants. Intense excitement seized him. He stepped toward the mass; with his spear he felt it. It was the carcass of a huge cayman, already reduced to a skeleton, and which the current of the Rio Negro had swept into the bed of the Amazon. Benito recoiled, and, in spite of the assertions of the pilot, the thought recurred to him that some living cayman might even then be met with in the deeps near the Bar of Frias!

But he repelled the idea, and continued his progress, so as to reach the bottom of the depression.

And now he had arrived at a depth of from eighty to a hundred feet, and consequently was experiencing a pressure of three atmospheres. If, then, this cavity was also drawn blank, he would have to suspend his researches.

Experience has shown that the extreme limit for such submarine explorations lies between a hundred and twenty and a hundred and thirty feet, and that below this there is great danger, the human organism not only being hindered from performing his functions under such a pressure, but the apparatus failing to keep up a sufficient supply of air with the desirable regularity.

But Benito was resolved to go as far as his mental powers and physical energies would let him. By some strange presentiment he was drawn toward this abyss; it seemed to him as though the corpse was very likely to have rolled to the bottom of the hole, and that Torres, if he had any heavy things about him, such as a belt containing either money or arms, would have sunk to the very lowest point. Of a sudden, in a deep hollow, he saw a body through the gloom! Yes! A corpse, still clothed, stretched out like a man asleep, with his arms folded under his head!

Was that Torres? In the obscurity, then very dense, he found it difficult to see; but it was a human body that lay there, less than ten paces off, and perfectly motionless!

A sharp pang shot through Benito. His heart, for an instant, ceased to beat. He thought he was going to lose consciousness. By a supreme effort he recovered himself. He stepped toward the corpse.

Suddenly a shock as violent as unexpected made his whole frame vibrate! A logn whip seemed to twine round his body, and in spite of the thick diving-dress he felt himself lashed again and again.

"A gymnotus!" he said.