And their purpose was to utterly annihilate the enemy that had so unexpectedly come upon them.  It did not matter to them that Tom and the others had arrived in an airship.  The strange craft had no superstitious terror for them, as it had for the simpler blacks.

“Bless my multiplication tables!” cried Mr. Damon.  “What a mob of them!”

“Almost too many!” murmured Tom Swift, who was rapidly firing his electric rifle at them.  “We can never hope to drive them back, I’m afraid.”

Indeed from every side of the plain, and even from the depths of the jungle the red dwarfs were now pouring.  They yelled most horribly, screaming in rage, brandishing their spears and clubs, and keeping up an incessant fire of big arrows from their bows, and smaller ones from the blowguns.

As yet none of our friends had been hit, for they were sheltered in the airship, and as the windows were covered with a mesh of wire, to keep out insects, this also served to prevent the arrows from entering.  There were loopholes purposely made to allow the rifles to be thrust out.

Mercifully, Tom and the others fired only to disable, and not to kill the red pygmies.  Wounded in the arms or legs, the little savages would be incapable of fighting, and this plan was followed.  But so fierce were they that some, who were wounded twice, still kept up the attack.

Tom’s electric rifle was well adapted for this work, as he could regulate the charge to merely stun, no matter at what part of the body it was directed.  So he could fire indiscriminintly, whereas the others had to aim carefully.  And Tom’s fire was most effective.  He disabled scores of the red imps, but scores of others sprang up to take their places.

After their first rush the pygmies had fallen back before the well-directed fire of our friends, but as their chiefs and head men urged them to the attack again, they came back with still fiercer energy.  Some, more bold than the others, even leaped to the deck of the airship, and tried to tear the screens from the windows.  They partly succeeded, and in one casement from which Ned was firing they made a hole.

Into this they shot a flight of arrows, and one slightly wounded the bank clerk on the arm.  The wound was at once treated with antiseptics, after the window had been barricaded, and Ned declared that he was ready to renew the fight.  Tom, too, got an arrow scratch on the neck, and one of the barbs entered Mr. Durban’s leg, but the sturdy elephant hunter would not give up, and took his place again after the wound had been bandaged.

From time to time as he worked his electric gun, which had been charged to its utmost capacity, Tom glanced at the hut where the missionaries were prisoners.  There was no movement noticed about it, and no sound came from it.  Tom wondered what had happened inside—­he wondered what was happening as the battle progressed.

Fiercely the fight was kept up.  Now the red imps would be driven back, and again they would swarm about the airship, until it seemed as if they must overwhelm it.  Then the fire of the white adventurers was redoubled.  The electric rifle did great work, and Tom did not have to stop and refill the magazine, as did the others.