Before Tom and Ned reached the place whence Professor Bumper had called, they heard strange noises, other than the imploring voice of their friend. It seemed as though some great body was threshing about in the jungle, lashing the trees, bushes and leaves about, and when the two young men, followed by Mr. Damon, reached the scene they saw that, in a measure, this really accounted for what they heard.

Something like a great whip was beating about close to two trees that grew near together. And then, when the storm of twigs, leaves and dirt, caused by the leaping, threshing thing ceased for a moment, the onlookers saw something that filled them with terror.

Between the two trees, and seemingly bound to them by a great coiled rope, spotted and banded, was the body of Professor Bumper. His arms were pinioned to his sides and there was horror and terror on his face, that looked imploringly at the youths from above the topmost coil of those encircling him.

"What is it?" cried Mr. Damon, as he ran pantingly up. "What has caught him? Is it the giant iguana?"

"It's a snake--a great boa!" gasped Tom. "It has him in its coils. But it is wound around the trees, too. That alone prevents it from crushing the professor to death.

"Ned, be ready with your rifle. Put in the heaviest charge, and watch your chance to fire!"

The great, ugly head of the boa reared itself up from the coils which it had, with the quickness of thought, thrown about the man between the two trees. This species of snake is not poisonous, and kills its prey by crushing it to death, making it into a pulpy mass, with scarcely a bone left unbroken, after which it swallows its meal. The crushing power of one of these boas, some of which reach a length of thirty feet, with a body as large around as that of a full-grown man, is enormous.

"I'm going to fire!" suddenly cried Tom. He had seen his chance and he took it. There was the faint report--the crack of the electric rifle-- and the folds of the serpent seemed to relax.

"I see a good chance now," added Ned, who had taken the small charge from his weapon, replacing it with a heavier one.

His rifle was also discharged in the direction of the snake, and Tom saw that the hit was a good one, right through the ugly head of the reptile.

"One other will be enough to make him loosen his coils!" cried Tom, as he fired again, and such was the killing power of the electric bullets that the snake, though an immense one, and one that short of decapitation could have received many injuries without losing power, seemed to shrivel up.

Its folds relaxed, and the coils of the great body fell in a heap at the roots of the two trees, between which the scientist had been standing.

Professor Bumper seemed to fall backward as the grip of the serpent relaxed, but Tom, dropping his rifle, and calling to Ned to keep an eye on the snake, leaped forward and caught his friend.

"Are you hurt?" asked Tom, carrying the limp form over to a grassy place. There was no answer, the savant's eyes were closed and he breathed but faintly.

Ned Newton fired two more electric bullets into the still writhing body of the boa.

"I guess he's all in," he called to Tom.

"Bless my horseradish! And so our friend seems to be," commented Mr. Damon. "Have you anything with which to revive him, Tom?"

"Yes. Some ammonia. See if you can find a little water."

"I have some in my flask."

Tom mixed a dose of the spirits which he carried with him, and this, forced between the pallid lips of the scientist, revived him.

"What happened?" he asked faintly as he opened his eyes. "Oh, yes, I remember," he added slowly. "The boa----"

"Don't try to talk," urged Tom. "You're all right. The snake is dead, or dying. Are you much hurt?"

Professor Bumper appeared to be considering. He moved first one limb, then another. He seemed to have the power over all his muscles.

"I see how it happened," he said, as he sat up, after taking a little more of the ammonia. "I was following the iguana, and when the big lizard came to a stop, in a little hollow place in the ground, at the foot of those two trees, I leaned over to slip a noose of rope about its neck. Then I felt myself caught, as if in the hands of a giant, and bound fast between the two trees."

"It was the big boa that whipped itself around you, as you leaned over," explained Tom, as Ned came up to announce that the snake was no longer dangerous. "But when it coiled around you it also coiled around the two trees, you, fortunately slipping between them. Had it not been that their trunks took off some of the pressure of the coils you wouldn't have lasted a minute."

"Well, I was pretty badly squeezed as it was," remarked the professor. "I hardly had breath enough left to call to you. I tried to fight off the serpent, but it was of no use."

"I should say not!" cried Mr. Damon. "Bless my circus ring! one might as well try to combat an elephant! But, my dear professor, are you all right now?"

"I think so--yes. Though I shall be lame and stiff for a few days, I fear. I can hardly walk."

Professor Bumper was indeed unable to go about much for a few days after his encounter with the great serpent. He stretched out in a hammock under trees in the camp clearing, and with his friends waited for the possible return of Tolpec and the porters.

Ned and Tom made one or two short hunting trips, and on these occasions they kept a lookout in the direction the Indian had taken when he went away.

"For he's sure to come back that way--if he comes at all," declared Ned; "which I am beginning to doubt."

"Well, he may not come," agreed Tom, who was beginning to lose some of his first hope. "But he won't necessarily come from the same direction he took. He may have had to go in an entirely different way to get help. We'll hope for the best."

A week passed. Professor Bumper was able to be about, and Tom and Ned noticed that there was an anxious look on his face. Was he, too, beginning to despair?

"Well, this isn't hunting for golden idols very fast," said Mr. Damon, the morning of the eighth day after their desertion by the faithless Jacinto. "What do you say, Professor Bumper; ought we not to start off on our own account?"

"We had better if Tolpec does not return today," was the answer.

They had eaten breakfast, had put their camp in order, and were about to have a consultation on what was best to do, when Tom suddenly called to Ned, who was whistling:

"Hark!"

Through the jungle came a faint sound of singing --not a harmonious air, but the somewhat barbaric chant of the natives.

"It is Tolpec coming back!" cried Mr. Damon. "Hurray! Now our troubles are over t Bless my meal ticket! Now we can start!"

"It may be Jacinto," suggested Ned.

"Nonsense! you old cold-water pitcher!" cried Tom. "It's Tolpec! I can see him! He's a good scout all right!"

And then, walking at the head of a band of Indians who were weirdly chanting while behind them came a train of mules, was Tolpec, a cheerful grin covering his honest, if homely, dark face.

"Me come back!" he exclaimed in gutteral English, using about half of his foreign vocabulary.

"I see you did," answered Professor Bumper in the man's own tongue. "Glad to see you. Is everything all right?"

"All right," was the answer. "These Indians will take you where you want to go, and will not leave you as Jacinto did."

"We'll start in the morning!" exclaimed the savant his own cheerful self again, now that there was a prospect of going further into the interior. "Tell the men to get something to eat, Tolpec. There is plenty for all."

"Good!" grunted the new guide and soon the hungry Indians, who had come far, were satisfying their hunger.

As they ate Tolpec explained to Professor Bumper, who repeated it to the youths and Mr. Damon, that it had been necessary to go farther than he had intended to get the porters and mules. But the Indians were a friendly tribe, of which he was a member, and could be depended on.

There was a feast and a sort of celebration in camp that night. Tom and Ned shot two deer, and these formed the main part of the feast and the Indians made merry about the fire until nearly midnight. They did not seem to mind in the least the swarms of mosquitoes and other bugs that flew about, attracted by the light. As for Tom Swift and his friends, their nets protected them.

An early start was made the following morning. Such packages of goods and supplies as could not well be carried by the Indians in their head straps, were loaded on the backs of the pack- mules. Tolpec explained that on reaching the Indian village, where he had secured the porters, they could get some ox-carts which would be a convenience in traveling into the interior toward the Copan valley.

The march onward for the next two days was tiresome; but the Indians Tolpec had secured were as faithful and efficient as he had described them, and good progress was made.

There were a few accidents. One native fell into a swiftly running stream as they were fording it and lost a box containing some much-needed things. But as the man's life was saved Professor Bumper said it made up for the other loss. Another accident did not end so auspiciously. One of the bearers was bitten by a poisonous snake, and though prompt measures were taken, the poison spread so rapidly that the man died.

In due season the Indian village was reached. where, after a day spent in holding funeral services over the dead bearer, preparations were made for proceeding farther.

This time some of the bearers were left behind, and ox-carts were substituted for them, as it was possible to carry more goods this way,

"And now we're really off for Copan!" exclaimed Professor Bumper one morning, when the cavalcade, led by Tolpec in the capacity of head guide, started off. "I hope we have no more delays."

"I hope not, either," agreed Tom. "That Beecher may be there ahead of us."

Weary marches fell to their portion. There were mountains to climb, streams to ford or swim, sending the carts over on rudely made rafts. There were storms to endure, and the eternal heat to fight.

But finally the party emerged from the lowlands of the coast and went up in among the hills, where though the going was harder, the climate was better. It was not so hot and moist.

Not wishing to attract attention in Copan itself, Professor Bumper and his party made a detour, and finally, after much consultation with Tom over the ancient maps, the scientist announced that he thought they were in the vicinity of the buried city.

"We will begin test excavations in the morning," he said.

The party was in camp, and preparations were made for spending the night in the forest, when from among the trees there floated to the ears of our friends a queer Indian chant.

"Some one is coming," said Tom to Ned.

Almost as he spoke there filed into the clearing where the camp had been set up, a cavalcade of white men, followed by Indians. And at the sight of one of the white men Tom Swift uttered a cry.

"Professor Beecher!" gasped the young inventor.