and all said it was sailing toward
the lake.

When the lake was reached and a motor-boat had been found which would
take them out on the water, several men said they had seen the big gas
bag beginning to go down near Hemlock Island, the largest island in the
lake.

"If they have only landed there they may be all right," Mrs. Bobbsey
said. "Oh, hurry and get there, Dick!"

"We'll hurry all we can," her husband told her, as they got into the
boat to continue the search. "But this is a bad storm. We must be
careful."

CHAPTER XVIII

ON THE ROCKS

The whole world seemed a very dreary and unhappy place to Mr. and Mrs.
Bobbsey as they started off in the motor-boat to look for Flossie and
Freddie. In the first place, if one of the little Bobbsey twins had just
been lost--plain lost--as Flossie was in the cornfield, it would have
been sad enough. But when both tots were missing, and when the last seen
of them had been a sight of them shooting away in a balloon through a
gathering storm, well, it was enough to make any father and mother feel
very unhappy.

Besides this, there was the rain, and as the motor-boat, in charge of
Captain Craig, swung out into the lake, the big, pelting drops came down
harder than ever.

"Oh, what a sad, sad day!" sighed Mrs. Bobbsey. "And it started off so
happily, too!"

"Perhaps it will end happily," said Mr. Bobbsey, hopefully. "It will not
be night for several hours yet, and before then we may find Flossie and
Freddie. In fact I'm sure we shall!"

"I think so, too," declared Mr. Trench, the owner of the balloon. "That
craft of mine wasn't filled with enough gas to go far, and it had to
come down soon."

"But where would it come down? That's the point!" cried Mrs. Bobbsey.
"If it came down in the lake----"

"It's on Hemlock Island, take my word for it!" growled out Captain
Craig, in whose motor-boat the searching party was riding. It was not
because he was cross that his voice had a growling sound. It was just
naturally hoarse. He was out on the water so much, often in the cold and
rain, that he seemed to have an everlasting cold. "We'll find the
balloon and the children, too, on Hemlock Island," he went on. "Half a
dozen men I talked to, just before you came, said they saw something big
and black, like an airship, swooping down on the island. We'll find 'em
there, never fear!"

"How far are we from Hemlock Island?" asked Mr. Bobbsey of Captain
Craig, when they had bee