He little knew how soon he would have to put his plan into effect.

They arrived safely at Majumba, the African coast city, and for two days Tom was kept busy superintending the unloading of the parts of his airship.  But it was safely taken ashore, and he and his friends hired a disused warehouse in which to work at reassembling the Black Hawk.

Tom had everything down to a system, and, in less than a week the aircraft was once more ready to be sent aloft.  It was given a try-out, much to the astonishment of the natives, and worked perfectly.  Then Tom and his friends busied themselves laying in a stock of provisions and stores for the trip into the interior.

They made inquiries about the chances of getting ivory and were told that they were good if they went far enough into the jungle and forests, for the big beasts had penetrated farther and farther inland.

They also tried to get some news regarding the captive missionaries, but were unsuccessful nor could they learn what had become of Tomba, who had brought the dire news to civilization.

“It’s too soon to hope for anything yet,” said Mr. Anderson.  “Wait until we get near the country of the red pygmies.”

“And then it may be too late,” said Tom in a low voice.

It was two weeks after their arrival in Majumba that Tom announced that all was in readiness.  The airship was in perfect working order, it was well stocked with food, arms, articles and trinkets with which to trade among the natives, spare parts for the machinery, special tools and a good supply of the chemicals needed to manufacture the lifting gas.

Of course Tom did not leave behind his electric weapon and Mr. Durban and the others took plenty of ammunition for the ordinary rifles which they carried.

One morning, after cabling to his father that they were about to start, Tom gave a last careful look to his airship, tested the motor and dynamos, took a hasty survey of the storeroom, to see that nothing had been forgotten, and gave the word to get aboard.

They took their places in the cabin.  Outside a crowd of natives, and white traders of many nationalities had gathered.  Tom pulled the starting lever.  The Black Hawk shot across a specially prepared starting ground, and, attaining sufficient momentum, suddenly arose into the air.

There was a cheer from the watching crowd, and several superstitious blacks, who saw the airship for the first time, ran away in terror.

Up into the blue atmosphere Tom took his craft.  He looked down on the city over which he was flying.  Then he pointed the prow of the Black Hawk toward the heart of the dark continent.

“Off for the interior!” he murmured.  “I wonder if we’ll ever get out again?”

No one could answer.  They had to take their chances with the dangers and terrors of elephant land, and with the red pygmies.  Yet Tom Swift was not afraid.