"Yes, there, there!" replied Thalcave, pointing with his finger to a species of gigantic walnut-tree, which raised its solitary head above the waters.

His companions needed no urging forward now; this tree, so opportunely discovered, they must reach at all hazards. The horses very likely might not be able to get to it, but, at all events, the men would, the current bearing them right down to it.

Just at that moment Tom Austin's horse gave a smothered neigh and disappeared. His master, freeing his feet from the stirrups, began to swim vigorously.

"Hang on to my saddle," called Glenarvan.

"Thanks, your honor, but I have good stout arms."

"Robert, how is your horse going?" asked his Lordship, turning to young Grant.

"Famously, my Lord, he swims like a fish."

"Lookout!" shouted the Major, in a stentorian voice.

The warning was scarcely spoken before the enormous billow, a monstrous wave forty feet high, broke over the fugitives with a fearful noise. Men and animals all disappeared in a whirl of foam; a liquid mass, weighing several millions of tons, engulfed them in its seething waters.

When it had rolled on, the men reappeared on the surface, and counted each other rapidly; but all the horses, except Thaouka, who still bore his master, had gone down forever.

"Courage, courage," repeated Glenarvan, supporting Paganel with one arm, and swimming with the other.

"I can manage, I can manage," said the worthy savant. "I am even not sorry--"

But no one ever knew what he was not sorry about, for the poor man was obliged to swallow down the rest of his sentence with half a pint of muddy water. The Major advanced quietly, making regular strokes, worthy of a master swimmer. The sailors took to the water like porpoises, while Robert clung to Thaouka's mane, and was carried along with him. The noble animal swam superbly, instinctively making for the tree in a straight line.

The tree was only twenty fathoms off, and in a few minutes was safely reached by the whole party; but for this refuge they must all have perished in the flood.

The water had risen to the top of the trunk, just to where the parent branches fork out. It was consequently, quite easy to clamber up to it. Thalcave climbed up first, and got off his horse to hoist up Robert and help the others. His powerful arms had soon placed all the exhausted swimmers in a place of security.

But, meantime, Thaouka was being rapidly carried away by the current. He turned his intelligent face toward his master, and, shaking his long mane, neighed as if to summon him to his rescue.

"Are you going to forsake him, Thalcave?" asked Paganel.

"I!" replied the Indian, and forthwith he plunged down into the tumultuous waters, and came up again ten fathoms off. A few instants afterward his arms were round Thaouka's neck, and master and steed were drifting together toward the misty horizon of the north.

CHAPTER XXIII A SINGULAR ABODE

THE tree on which Glenarvan and his companions had just found refuge, resembled a walnut-tree, having the same glossy foliage and rounded form. In reality, however, it was the OMBU, which grows solitarily on the Argentine plains. The enormous and twisted trunk of this tree is planted firmly in the soil, not only by its great roots, but still more by its vigorous shoots, which fasten it down in the most tenacious manner. This was how it stood proof against the shock of the mighty billow.

This OMBU measured in height a hundred feet, and covered with its shadow a circumference of one hundred and twenty yards. All this scaffolding rested on three great boughs which sprang from the trunk. Two of these rose almost perpendicularly, and supported the immense parasol of foliage, the branches of which were so crossed and intertwined and entangled, as if by the hand of a basket-maker, that they formed an impenetrable shade. The third arm, on the contrary, stretched right out in a horizontal position above the roaring waters, into which the lower leaves dipped. There was no want of room in the interior of this gigantic tree, for there were great gaps in the foliage, perfect glades, with air in abundance, and freshness everywhere. To see the innumerable branches rising to the clouds, and the creepers running from bough to bough, and attaching them together while the sunlight glinted here and there among the leaves, one might have called it a complete forest instead of a solitary tree sheltering them all.