Meanwhile Tom and his friends had been on the lookout for any one who might be trailing them.  But they saw no suspicious characters among the passengers, and, gradually, they began to feel that they had left their enemies behind.

The weather was pleasant, and the voyage very enjoyable.  Tom and the others had little to do, and they were getting rather impatient for the time to come when they could put the airship together, and sail off over the jungle, to get moving pictures of the elephants.

“Have you any films in the camera now?” asked Ned of his chum on day, as they sat on deck together.

“Yes, it’s all ready for instant use.  Even the storage battery is charged.  Why?”

“Oh, I was just wondering.  I was thinking we might somehow see something we could take pictures of.”

“Not much out here,” said Tom, as he looked across the watery expanse.  As he did so, he saw a haze of smoke dead ahead.  “We’ll pass a steamer soon,” he went on, “but that wouldn’t make a good picture.  It’s too common.”

As the two lads watched, the smoke became blacker, and the cloud it formed grew much larger.

“They’re burning a lot of coal on that ship,” remarked Ned.  “Must be trying for a speed record.”

A little later a sailor stationed himself in the crow’s nest, and focused a telescope on the smoke.  An officer, on deck, seemed to be waiting for a report from the man aloft.

“That’s rather odd,” remarked Ned.  “I never knew them to take so much interest in a passing steamer before; and we’ve gone by several of late.”

“That’s right,” agreed Tom.  “I wonder—­”

At that moment the officer, looking up, called out: 

“Main top!”

“Aye, aye, sir,” answered the sailor with the glass.  “She’s a small steamer, sir, and she’s on fire!”

“That’s what I feared.  Come down.  I’ll tell the captain.  We must crowd on all steam, and go to the rescue.”

“Did you hear that?” cried Ned to Tom, as the officer hurried to the bridge, where the captain awaited him.  “A steamer on fire at sea, Tom! why don’t you—­”

“I’m going to!” interrupted the young inventor, as he started for his cabin on the run.  “I’m going to get some moving pictures of the rescue!  That will be a film worth having.”

A moment later the Belchar, the vessel on which our friends had embarked, increased her speed, while sudden excitement developed on board.

As the Belchar approached the burning steamer, which had evidently seen her, and was making all speed toward her, the cloud of smoke became more dense, and a dull flame could be seen reflected in the water.

“She’s going fast!” cried Mr. Nestor, as he joined Ned on deck.

“Bless my insurance policy!” cried Mr. Damon.  “What a strange happening!  Where’s Tom Swift?”

“Gone for his camera,” answered his chum.  “He’s going to get some pictures of the rescue.”