the smoke.

"Here is what the fire consists of," declared Fred presently, when he
caught a whisp of it on his arm. "It's nothing but oil-soaked waste.
They must have had a whole lot of it at that plant, and one of the
explosions sent it high into the air and scattered it in every
direction."

The boys continued on their way for a few minutes, and then ran into
another cloud of smoke. This was of a peculiar bluish-green cast, and
seemed so sulphurous they were nearly choked by it.

"Listen!" burst out Andy. "I think I heard somebody calling."

He held up one hand for silence, and all listened attentively. In
spite of the roaring of the flames, which were now devouring several
of the buildings at the shell-loading plant, and the continual popping
of some of the smaller shells, all heard a frantic cry for assistance.

"It's somebody calling for help!"

"Where is he?"

"I think the cry came from over yonder," said Jack, in answer to the
latter question. "Let's pull over there and see."

All were willing, and the four once more bent to their oars, sending
the rowboat through the bluish-green smoke, which almost choked and
blinded them.

"Hello there!" yelled Fred. "Where are you?"

"Help! Help!" came the cry from off to their left. "Help! Save me!"

The rowboat was turned in that direction, and a few seconds later the
Rover boys caught sight through the smoke of a water-logged rowboat to
which an elderly man, dressed in the garb of a workman, was clinging.

"Help me! Help me! I can't hang on much longer!" gasped the man, as
soon as he saw the boys.

"Sure, we'll help you," declared Jack. "Go slow now," he cautioned his
cousins. "We don't want to knock him off into the water."

With care the rowboat was brought around so that they came up
alongside of the elderly man. He was glad enough to turn from his
water-logged craft to the other boat. But he was well-nigh exhausted,
and the Rovers had not a little trouble in getting him on board.

"Tell you what--I'm mighty glad you lads came along," panted the old
man, when he was safe. "I couldn't have held out much longer. This is
something terrible, ain't it? Say, would you mind hooking that boat
fast and pulling it to shore? It belongs to me, and I ain't so
wealthy that I can afford to lose it. Besides, it's got some of my
things in it."

"We'll take it along unless it keeps us back too much," answered Jack.
And then he bent down, got hold of the bowline of the