suddenly a bushy bead, with a black face, horribly distorted by passion, appeared at the window furthest from where professor grimcke was standing.

the right hand was raised and in the act of poising a javelin to hurl at the white man; but the latter, with an incredibly quick movement, brought his winchester to a level and fired.

the bronze skull was shattered as though it were a rotten apple, and the murhapa, with a resounding shriek, went backward in the darkness.

a slight rustling at the other window drew the white man's attention thither, and, without lowering his weapon, he let fly at a group who were simply peering within, evidently believing there was no call to use their javelins.

another screech told that the bullet had found its mark, and the other faces vanished.

then grimcke stepped out from the wall to gain a view of the opening which answered for a door. a rustling there told him a crowd were gathering, but they had taken warning just in time to avoid a third shot. then he slipped a couple more cartridges from his belt into the magazine, so as to keep it full, and awaited the next step in this extraordinary business.

"i've about a hundred left," he reflected, "and that's enough to keep things on a jump, if i can dodge their javelins."

meanwhile, jared long was not idle. he had but the opening at the rear to watch, and he did the duty well. almost at the moment that his comrade fired his first shot, he descried the figure of a murhapa trying to steal into the apartment without detection; but just enough of the moonlight that was shut from the front doors and windows, reached the rear of the building, to disclose the outlines of the head and shoulders, as he began stealthily creeping into the building.

bippo had discovered the peril at the same moment, and clutched the arm of his master with a nervous intensity of terror. long impatiently shook him off, and, with the same cool quickness of professor grimcke, drove a bullet through the head of the dusky miscreant, who was slain so suddenly that he rolled convulsively backward, without any outcry.

almost at the same instant, a second native emitted a wild shout. he was directly behind the first and the latter lurched against him, causing such fright that he leaped back several feet with the involuntary cry fully understood by all whose ears it reached.

long stood as rigid as a statue for several minutes, waiting for another chance, but none presented. then he reflected that his position was much more favorable than grimcke's, for not only had he but the single opening to guard, but his apartment was so shrouded in gloom that the sharpest-eyed warrior could not locate him from the outside.

the new englander stepped to the door communicating with the front apartment and, barely showing himself, spoke:

"i can attend to the window on the right, professor; leave that to me, while you watch the door and the other one."

"thanks," returned his friend; "i think there is a little too much light in this part of the house."

moving quickly to the hearth he heaped the ashes with his foot upon the blazing embers, until they were so smothered that only a few tiny twists of flame struggled through the covering. this left the place in such darkness that a sense of security instantly came to him.

"good!" called the new englander, who could no longer be discerned; "that makes matters more nearly equal!"

although, as we have said, the moonlight was substantially shut off from the front of the heavy structure, yet the moon itself, being full, so illumined the surroundings that it was quite easy to distinguish the head and figure of any one of their enemies the instant he presented himself at one of the openings.

what both the defenders feared was, that the savages would make a sudden rush and force themselves within the cabin in spite of the disastrous reception they were sure to be given. such an essay was certain to result in the overthrow of the whites, but the murhapas must have realized the cost it would be to them. brave as they were, they hesitated to incur the consequences until other means had failed.

professor ernest grimcke now did a most daring thing. the fierce welcome he had given the attacking murhapas resulted in their temporary demoralization. knowing they would speedily recover, he decided to take advantage of the panic by an attempt to intensify it.

striding to the door he paused on the very threshold and peered out upon the large space in his field of vision.

fully a hundred savages were in sight. apparently they had been crowding around the entrance when the shots from within caused a hasty scattering. they had halted a dozen yards or so away, where they were talking excitedly, still frightened and enraged, and with no thought of relinquishing the fight.

they had withdrawn so far from the front of the building that they were in the strong moonlight, and consequently in full view of the white man, who saw others of the natives hurrying from the right and left. among them were women and children and the confusion and excitement were fearful.

standing thus, grimcke again raised his repeater and deliberately opened fire on the crowd. it seemed cruel, but it was an act of self-defence, for those people were clamoring for the lives of the two men within, and would not be satisfied until they were at their mercy.

it was a strange scene that followed. the interior of the building being dark, while the moonlight failed to touch the front, the figure of the white man was invisible to the dusky wretches howling on the outside.

all at once, from the black opening of the building, came the crash of the repeating winchester. spouts of fire shot out into the gloom in terrific succession, as if fiery serpents were darting their heads in different directions; for the marksman aimed, quickly to the right, to the left and to the front, never pausing until he had discharged half a score of shots.

the panic for a minute or two was indescribable. men, women and children shrieked and scattered for the nearest available shelter. behind the buildings and down the river bank they dashed, stumbled and rolled, until, but for the tragic nature of the scene, the white man would have smiled.

but he had done enough, and he stepped back within the room to replenish the magazine of his rifle.

jared long had been drawn into the room by the furious fusillade, and now put the startling question whether advantage could not be taken of the panic to make a sudden dash for the woods. it would never do to make for the boat still resting against the shore, for it would be filled with poisoned javelins before they could shove out into the xingu.

"i believe we can," replied the professor; "it will take them some minutes to get over their panic and that will be enough for us."

"let us leave by the rear," said long, "for i don't think that is so well guarded."

the two turned to attempt the dash for freedom, when a cry from bippo struck them.

"stay here," exclaimed the new englander, fearing that a diversion was on foot; "and i'll attend to him!"

he was back in the apartment in an instant. the light on the hearth having been extinguished, the gloom in this portion of the building was impenetrable, but a fearful struggle of some kind was going on. some animal or person had got within and grappled bippo who was fighting like a tiger.

had the new englander been able to distinguish the combatants, he would have ended the contest in a twinkling, but though the two rolled against his feet, he dared not fire through fear of hurting his friend.

"are you under or on top?" he asked, bending downward at the moment he knew from the peculiar sounds the foes had become stationary.

"he on top," was the doleful response.

long extended his right hand to learn precisely how matters stood, or rather lay, when it came in contact with the arm of a murhapa in the act of raising it aloft to bury his knife in the body of the helpless bippo, who was at the mercy of the savage, holding him inextricably in his grasp.

the american secured a firm hold of the forearm, and with a powerful wrench, not only jerked the miscreant free, but flung him from one side of the room clean to the door, where he was visible in the faint light beyond.

evidently concluding that his mission in that place was over, he nimbly came to his feet and shot like a rocket through the opening.

the new englander was in no mood for sentimentality, and, he levelled his weapon with the intention to kill; but quick as he was, he was just a fraction of a minute too late, and, much to his chagrin, the dusky wretch got away unharmed.

long darted into the front room, ready for the proposal he had made just before.

the professor was peering out, seemingly debating whether it was not advisable to re-open his bombardment.

"it beats creation," he remarked, as his friend appeared at his elbow, "how quickly those fellows rally; their heads are popping up in every direction, and it won't do to try to steal out this way."

"but i suggested the rear," reminded long.

"let's see how matters look there."

the survey from the other opening was disappointing. although all the murhapas had been affected in a greater or less degree by the panic, yet it was more incomplete at the rear, because the confusing volley had not come from that direction.

there seemed to be fully as many warriors on this side, which, with the exception of the river, was quite similar in appearance to the other. the shadowy figures were observed moving noiselessly in a dozen different directions, their heads bent down and their bodies crouching, as if in expectation of a shot, but, at the same time, they were not to be frightened off by any fusilade from within.

"we're just too late," remarked the professor, quick to take in every point of the situation; "we might have done it a minute ago, but they are watching too closely now."

"let's open again," suggested the new englander.

"better wait awhile; they can be stampeded easier then than now," was the reply of the professor.

during this lull, when it may be said the defenders were becoming accustomed to the siege, they had time to give a few minutes' thought to their absent friends, fred ashman and ziffak, regarding whom it was natural to feel great curiosity.

they believed themselves warranted in hoping for the best, so far as ashman was concerned. he had probably strolled some distance, and must have been warned by the firing of the professor's winchester from the front, of the serious danger in which his friends were involved. if all had gone well with the youth up to that time, he ought to be wise enough to get away without an instant's delay. what was feared was, that in his anxiety to help his comrades, he would run into a peril from which he could not extricate himself.

the real hope for the youth was centered on ziffak. believing he had gone forth to look after ashman, they were confident he would speedily get upon his track. if so, he would not permit him to return to the village.

from what the reader has been told, it will be seen that the defenders were not far off in their conjectures.

but, when they came to speculate upon the part that the head chieftain was likely to take, affecting grimcke and long, they were all at sea. it would ever be a source of wonder that he had been transformed from a relentless enemy into the strongest of friends, but they fully realized that such friendship must have its bounds.

ziffak might not shrink from using very plain speech when talking face to face with his brother, but it was hardly to be supposed that he would raise his arm against his authority. at the time ziffak made known the probability that the explorers might be compelled to take their departure that evening, he gave no intimation of any purpose of helping them to resist such an order.

accustomed as he was to lead the warlike murhapas in battle, he might well hesitate to ask them to turn their weapons against the king, and if he should presume on such treason, all the probabilities were that such weapons would be turned against the head chieftain himself.