TWO reports rent the air. Without an outcry the big eland collapsed. A hyena, too, had been hit by Bob’s rifle.

“One good turn done,” said Mr. Lewis, handing his rifle to his gun bearer.

“Wait till I shoot the rest of those hyenas,” came from Bob, who was taking aim with a high-velocity .22 rifle.

“Um get bigger gun. No kill um with little gun.” Noko was watching Bob curiously.

“Watch me and see,” smiled Bob.

Using his knowledge of marksmanship, the youth killed all of the hyenas by sending bullets through the eye to the brain. The stupid animals had not made the slightest move to flee, even though they saw their companions go down.

But scarcely had the cloud of smoke lifted when the explorers saw something else making for the body of the eland. Three large black vultures perched on the carcass.

More carefully aimed bullets from Bob’s rifle finished them instantly.

“Ready now?” chuckled Mr. Holton.

“Sure,” Bob answered. “That job’s over. Somehow I couldn’t leave without letting those hyenas and vultures have it.”

A little farther on, the adventurers came to a narrow trail that wound through the tall grass. As it headed in their direction, they followed it.

For the last ten minutes Bob and Joe had fallen to the rear of the safari. Now, when they returned to join their fathers, Mr. Lewis turned to them.

“Noko says there may be a native village a little farther on,” he said. “Howard and I think it might be best to make for it, because the blacks may be able to tell us of some big game in this vicinity. We’d like especially to have a fine leopard skin.”

“Leopard! Boy! Sounds exciting,” grinned Joe. “Here’s hoping we see one—or more, for that matter.”

They trudged on for over an hour. Then, when they were beginning to fear that no village was near, they rounded a bend in the bushes and found themselves facing a group of thatched huts.

“Came to it at last,” mused Bob. “But—where are the people? Looks like nobody’s at home.”

“Maybe they’ve gone visiting,” remarked Joe with a laugh.

Mr. Holton suggested that they move on into the village to see if there was any evidence of recent human habitation.

Leaving the bearers at a little clearing to wait, the four Americans and Noko walked toward the grass huts, keeping on the alert for anything human or animal.

“Looks like it’s deserted, all right,” remarked Joe. “Not a soul anywhere.”

“What’s that?” cried Bob suddenly, stopping at once.

“What?” questioned his chum.

“Sounded like—— Come on, Joe. Let’s go around this hut and see what we can see.”

The youths left the naturalists and Noko and made their way to the other side of a large thatched house.

Then, horror stricken, they saw what had caused Bob to utter his sudden exclamation.

Coiled but a few scant feet away was a long black mamba, the most poisonous snake of Africa. It was eyeing the human invaders staringly, apparently with evil purpose.

For one awful moment the youths gazed in terrible fascination, unable to take their eyes from the hideous reptile. Then, sensing the need for flight, they turned to leave. But they hesitated.

“It’s going to strike!” gasped Joe. “And neither of us has a gun!”

Bob looked about wildly for some club or other weapon with which to defend himself and his friend, but saw none. For a second he thought of turning to run, but he soon realized that the deadly snake could probably move much faster than could he.

What greatly puzzled the youths was why the mamba appeared to be taking the aggressive. Perhaps, however, it was angered because frightened.

Just then the youths heard a shout from Mr. Lewis and then the report of a rifle.

The snake’s head was shattered into a horrid pulp, which almost sickened the boys. It writhed about feebly, then was still.

Mr. Lewis and Mr. Holton rushed toward their sons.

“You sure fired that shot in time,” said Bob with a shudder. “I was beginning to think it was all over with us.”

“It was a terribly narrow escape,” breathed Mr. Holton, wiping the perspiration from his brow. “We should have warned you about mambas.”

“Why?” asked Bob. “They aren’t here any more than anywhere else, are they?”

“Yes,” returned Mr. Holton emphatically. “A deserted village nearly always contains at least one mamba. For some reason they like to pick on such a place. But the main thing now,” he added, “is that you’re still alive.”

With one last glance at the dead reptile the explorers turned toward the safari. As they passed through the village they kept a close watch for any more of the dreaded snakes, but saw none near. They did see another quite a distance away, although it did not apparently catch sight of them.

“I’ve been wondering just where the villagers are and why they left their huts,” remarked Mr. Lewis, when they had rejoined the others of the expedition.

“Maybe those mambas drove them out,” suggested Bob, but Noko shook his head.

“No rain now, and dey go to place where is water,” was the opinion voiced by the head native.

“By Jupiter! Perhaps you’re right, Noko,” exclaimed Joe’s father. “Well, then, if that is true, there is no use waiting for them to return. Let’s go.”

Under the expert leadership of the veteran Noko, the expedition was making good time toward the little-known Forest of Mystery. If their luck should hold, they would reach it in but a few days.

“According to Mr. Seabury, back in Mombasa, we should come to a very wide, shallow stream. A little beyond this is the Forest of Mystery,” said Mr. Holton, as that night they were camped at the foot of a little knoll. “We should be nearing that stream now.”

Mention of this out-of-the-way place revived the name of Thomas Seabury, the missing brother of the man in Mombasa.

“Wonder if we’ll find him,” mused Joe, gazing off into the dark depths of the jungle.

“Hard telling,” returned his friend. “About all we can do is to ask natives if they have seen or heard of him. And if they haven’t—well, it doesn’t look like there’ll be much chance of coming across him.”

“You’re right, Bob,” affirmed Mr. Lewis. “Africa is a very large place, and he might have left that unknown forest long before. But we’ll certainly do all we can to locate him.”

For two successive days the safari plunged on steadily without coming to the stream.

Late in the afternoon the explorers were crossing a stretch of open country when suddenly Mr. Lewis called a halt. He pointed to something that was coming toward them.

It was an impala, a species of antelope, and was evidently in the last stage of exhaustion. Running wildly and without aim, the animal was a pitiable sight.

Then the adventurers saw something else. Two African hunting dogs were pursuing the impala and were gaining rapidly. In but a short time they would be upon it.

“Quick!” exclaimed Mr. Holton, grasping his rifle from its bearer. “We must shoot those dogs before they get that fine big antelope. Ben, you take the one ahead. I’ll pick the one behind. Now!”

Bang! Crack!

The sound of the guns was mingled with a last cry from one of the hunting dogs as it rolled over. The other had been killed instantly.

“Two less pests in the world,” murmured Mr. Lewis, and then, turning to Bob and Joe: “All the hunters in Africa couldn’t kill off as many beautiful harmless animals as the African hunting dog.”

“Why? How do they do it?” inquired Joe.

“They usually hunt in packs,” his father replied. “And the antelope or other animal that they go after is as good as doomed. They never give up till they get the one they’re after. Worst thing is, they kill new animals every day and eat only a small part of the flesh. Then they single out more.”

“The pests!” growled Bob. “From now on I’m going to plug every one I see. They——”

He did not finish, for just at that moment the party emerged from a thick jungle growth to see a wide stream just ahead. Beyond it was an endless mass of towering trees, which grew so close together as to form a veritable jungle.

Bob uttered a cry of delight.

“The Forest of Mystery!” he broke out. “We’ve found it!”