The Caspian Sea is a volcanic depression. Into it flow the waters of the Volga, the Ural, the Kour, the Kouma, the Jemba, and others. Without the evaporation which relieves it of its overflow, this basin, with an area of 17,000 square miles, and a depth of from sixty to four hundred feet, would flood the low marshy ground to its north and east. Although it is not in communication with the Black Sea or the Sea of Aral, being at a much lower level than they are, it contains an immense number of fish--such fish, be it understood, as can live in its bitter waters, the bitterness being due to the naptha which pours in from the springs on the south.

The crew of the "Albatross" made no secret of their delight at the change in their food the fishing would bring them.

"Look out!" shouted Turner, as he harpooned a good-size fish, not unlike a shark.

It was a splendid sturgeon seven feet long, called by the Russians beluga, the eggs of which mixed up with salt, vinegar, and white wine form caviar. Sturgeons from the river are, it may be, rather better than those from the sea; but these were welcomed warmly enough on board the "Albatross."

But the best catches were made with the drag-nets, which brought up at each haul carp, bream, salmon, saltwater pike, and a number of medium-sized sterlets, which wealthy gourmets have sent alive to Astrakhan, Moscow, and Petersburg, and which now passed direct from their natural element into the cook's kettle without any charge for transport.

An hour's work sufficed to fill up the larders of the aeronef, and she resumed her course to the north.

During the fishing Frycollin had continued shouting and kicking at his cabin wall, and making a tremendous noise.

"That wretched nigger will not be quiet, then?" said Robur, almost out of patience.

"It seems to me, sir, he has a right to complain," said Phil Evans.

"Yes, and I have a right to look after my ears," replied Robur.

"Engineer Robur!" said Uncle Prudent, who had just appeared on deck.

"President of the Weldon Institute!"

They had stepped up to one another, and were looking into the whites of each other's eyes. Then Robur shrugged his shoulders. "Put him at the end of a line," he said.

Turner saw his meaning at once. Frycollin was dragged out of his cabin. Loud were his cries when the mate and one of the men seized him and tied him into a tub, which they hitched on to a rope--one of those very ropes, in fact, that Uncle Prudent had intended to use as we know.

The Negro at first thought he was going to be hanged. Not he was only going to be towed!

The rope was paid out for a hundred feet and Frycollin found himself hanging in space.

He could then shout at his ease. But fright contracted his larynx, and he was mute.

Uncle Prudent and Phil Evans endeavored to prevent this performance. They were thrust aside.

"It is scandalous! It is cowardly!" said Uncle Prudent, quite beside himself with rage.

"Indeed!" said Robur.

"It is an abuse of power against which I protest."

"Protest away!"

"I will be avenged, Mr. Robur."

"Avenge when you like, Mr. Prudent."

"I will have my revenge on you and yours."

The crew began to close up with anything but peaceful intentions. Robur motioned them away.

"Yes, on you and yours!" said Uncle Prudent, whom his colleague in vain tried to keep quiet.

"Whenever you please!" said the engineer.

"And in every possible way!"

"That is enough now," said Robur, in a threatening tone. "There are other ropes on board. And if you don't be quiet I'll treat you as I have done your servant!"

Uncle Prudent was silent, not because he was afraid, but because his wrath had nearly choked him; and Phil Evans led him off to his cabin.

During the last hour the air had been strangely troubled. The symptoms could not be mistaken. A storm was threatening. The electric saturation of the atmosphere had become so great that about half-past two o'clock Robur witnessed a phenomenon that was new to him.

In the north, whence the storm was traveling, were spirals of half-luminous vapor due to the difference in the electric charges of the various beds of cloud.