Dick Sand then recalled—­and very fortunately—­what he had read in “Livingstone’s Travels.”  More than once the daring doctor had nearly rested in these marshes, so treacherous under foot.

“Listen to me, my friends,” said he, going ahead.  “Try the ground before stepping on it.”

“In fact,” replied Tom, “they say that these grounds have been softened by the rain; but, however, it has not rained during these last days.”

“No,” replied Bat; “but the storm is not far off.”

“The greater reason,” replied Dick Sand, “why we should hurry and get clear of this swamp before it commences.  Hercules, take little Jack in your arms.  Bat, Austin, keep near Mrs. Weldon, so as to be able to help her if necessary.  You, Mr. Benedict—­Why, what are you doing, Mr. Benedict?”

“I am falling!” innocently replied Cousin Benedict, who had just disappeared as if a trap had been suddenly opened beneath his feet.

In fact, the poor man had ventured on a sort of quagmire, and had disappeared half-way in the sticky mud.  They stretched out their hands, and he rose, covered with slime, but quite satisfied at not having injured his precious entomologist’s box.  Acteon went beside him, and made it his duty to preserve the unlucky, near-sighted man from any new disasters.

Besides, Cousin Benedict had made rather a bad choice of the quagmire for his plunge.  When they drew him out of the sticky earth a large quantity of bubbles rose to the surface, and, in bursting, they emitted some gases of a suffocating odor.  Livingstone, who had been sunk up to his chest in this slime, compared these grounds to a collection of enormous sponges, made of black, porous earth, from which numerous streams of water spouted when they were stepped upon.  These places were always very dangerous.

For the space of half a mile Dick Sand and his companions must march over this spongy soil.  It even became so bad that Mrs. Weldon was obliged to stop, for she sank deep in the mire.  Hercules, Bat, and Austin, wishing to spare her the unpleasantness more than the fatigue of a passage across this marshy plain, made a litter of bamboos, on which she consented to sit.  Her little Jack was placed in her arms, and they endeavored to cross that pestilential marsh in the quickest manner.

The difficulties were great.  Acteon held Cousin Benedict firmly.  Tom aided Nan, who, without him, would have disappeared several times in some crevice.  The three other blacks carried the litter.  At the head, Dick Sand sounded the earth.  The choice of the place to step on was not made without trouble.  They marched from preference on the edges, which were covered by a thick and tough grass.  Often the support failed, and they sank to the knees in the slime.

At last, about five o’clock in the evening, the marsh being cleared, the soil regained sufficient firmness, thanks to its clayey nature; but they felt it damp underneath.  Very evidently these lands lay below the neighboring rivers, and the water ran through their pores.