saner than the globular interior of the aircraft,
divided into four wedge-shaped apartments.

Dr. Mundson also paused at the door, puzzled, hesitant.

"Someone has been here!" he exclaimed. "Look, Northwood! The bunk has
been occupied--the one in this cabin I had set aside for you."

He pointed to the disarranged bunk, where the impression of a head could
still be seen on a pillow.

"A tramp, perhaps."

"No! The door was locked, and, as you saw, the fence around this field
was protected with barbed wire. There's something wrong. I felt it on my
trip here all the way, like someone watching me in the dark. And don't
laugh! I have stopped laughing at all things that seem unnatural. You
don't know what is natural."

Northwood shivered. "Maybe someone is concealed about the ship."

"Impossible. Me, I thought so, too. But I looked and looked, and there
was nothing."

All evening Northwood had burned to tell the scientist about the
handsome stranger in the Mad Hatter Club. But even now he shrank from
saying that a man had vanished before his eyes.

Dr. Mundson was working with a succession of buttons and levers. There
was a slight jerk, and then the strange craft shot up, straight as a
bullet from a gun, with scarcely a sound other than a continuous
whistle.

"The vertical rising aircraft perfected," explained Dr. Mundson. "But
what would you think if I told you that there is not an ounce of
gasoline in my heavier-than-air craft?"

"I shouldn't be surprised. An electrical genius would seek for a less
obsolete source of power."

* * * * *

In the bright flare of the electric lights, the scientist's ugly face
flushed. "The man who harnesses the sun rules the world. He can make the
desert places bloom, the frozen poles balmy and verdant. You, John
Northwood, are one of the very few to fly in a machine operated solely
by electrical energy from the sun's rays."

"Are you telling me that this airship is operated with power from the
sun?"

"Yes. And I cannot take the credit for its invention." He sighed. "The
dream was mine, but a greater brain developed it--a brain that may be
greater than I suspect." His face grew suddenly graver.

A little later Northwood said: "It seems that we must be making fabulous
speed."

"Perhaps!" Dr. Mundson worked with the controls. "Here, I've cut her
down to the average speed of the ordinary airplane. Now you can see a
bit of the night scenery."