een tumbled down, completely closing the
tunnel.

"Well," said Graham, "it's over! Finished! They'll never get through
that!"

* * * * *

A full-throated cheer burst from the men below, a cheer that rang for
minutes as they realized they were free forever of the octopi, of the
cold underwater city, of the clutching tentacles. Graham grinned
broadly.

"Sound happy--eh?" he chuckled. "Say, Keith, it's good we've got those
two octopi our fighting cook killed. Knapp would never believe our
story without them!"

He stared curiously at his commander. Wells was standing quite still,
facing the teleview screen. A strange, far-away look was in his eyes.

"What's the matter, old man?" the first officer asked, smiling
straight at him. "Aren't you glad we won through?"

"Of course," answered Keith with a tired smile in return.

"But why did you look that way?" Graham persisted. And Keith Wells
told him:

"I was just wondering if Hemmy told the truth."

The Black Lamp

_By Captain S. P. Meek_

[Illustration: _"Look out!" He leaped to one side as he spoke._]

[Sidenote: Dr. Bird and his friend Carnes unravel another criminal web
of scientific mystery.]

"The clue, Carnes," said Dr. Bird slowly, "lies in those windows."

Operative Carnes of the United States Secret Service shook his head
before he glanced at the windows of the famous scientist's private
laboratory on the top floor of the Bureau of Standards.

"I usually defer to your knowledge, Doctor," he said, "but this time I
think you are off on the wrong foot. If the thieves came in through
the windows, what was their object in cutting that hole through the
roof? The marks are very plain and they indicate that the hole was cut
in some manner from the inside."

Dr. Bird smiled enigmatically.

"That is too evident for discussion," he replied. "I grant you that
the thieves entered from the roof through that hole. After they had
secured their booty they left by the same route. I presume that you
have noticed the marks on the roof where an aircraft of some sort,
probably a helicopter, landed and took off. A question of much greater
moment is that of what they did before they landed and cut the hole."

"I don't follow your reasoning, Doctor."

"Carnes, that hole was cut through the roof with a heavy saw. In
cutting it, the workers dislodged quite a little plaster which fell to
the floor and must have made a great deal of