still the dart kept on her course.

frank looked in vain for the signs of land described by captain bell. to him they did not exist.

he had no means of knowing at what depth they were.

but he knew that their situation was hourly growing more critical.

then prof. von bulow came to him.

“i have a request to make.

“if you should succeed in reaching home alive tell my wife that i sent her my love in my dying breath.”

frank took the scientist’s hand.

“of course i would do that,” he said. “but there is no more chance for me to reach home safely than for you.”

“i understand,” said von bulow, sadly; “but it is a comfort to me.”

“then i will promise,” said frank.

just at this moment came the climax.

barney came running into the cabin with his face as pale as chalk.

“misther frank!” he cried, “the chemical generator has failed to worruk, an’ the air is all going, sor!”

at once active measures were taken to meet the end.

the helmets were hurriedly brought and donned.

it was none too soon, for the air in the cabin was quickly exhausted. then the dart came to a stop, for it was useless to attempt to run it without the aid of the pneumatic engine.

the dart was securely anchored, and then, as lightly equipped as possible, the explorers set forth upon their apparently hopeless quest for land.

on and on they wandered.

what seemed like an interminable period elapsed.

still there was no sign of land.

von bulow had begun to give out.

all the others were more or less affected; at length the scientist sank down helpless.

but at the eleventh hour rescue came.

suddenly barney sprang up with a sharp cry. it was not heard by the others, but his action was seen.

he pointed to an object not many feet away and advancing toward them.

it was a man in a diver’s costume, with life line and rope. he came toward them with astonishment.

putting his helmet to frank’s, he shouted:

“who are you?”

“we are the crew of the submarine boat dart.”

and frank told his story, to which the diver listened with amazement.

“and i am john frisbie, of the thames diving company,” said the diver. “i am down here looking for the brig enterprise, sunk here two weeks ago.”

“what part of the sea is this?” asked frank.

“we are in the english channel.”

what followed needs but a few words to relate.

frank and the others were safely drawn up and aboard the english tug fortune. a few days later they were safe in london.

the great submarine expedition was at an end.

all hands returned to america.

frank reade, jr., and barney and pomp went back to readestown. frank at once began work upon a new invention.

captain bell recovered his gold by diving for it, but the dart was never raised, and to-day sleeps at the bottom of the english channel.

and this, dear reader, brings to a propitious end our story of submarine adventure.