a
lightning bolt, though that is sometimes visible as a ball of fire.
My electric rifle bullets are similar to a discharge of lightning,
except that they are invisible."

"But we saw the one just now," objected Ned.

"No, you didn't see the bullet," said Tom.

"You saw the illuminating flash which I send out just before I fire,
to reveal the object I am to hit. That is another part of my rifle
and is only used at night."

"You see I shoot out a ball of electrical fire which will disclose
the target, or the enemy at whom I am firing. As soon as that is
discharged the rifle automatically gets ready to shoot the electric
charge, and I have only to press the proper button, and the
'bullet,' as I call it, follows on the heels of the ball of light.
Do you see?"

"Perfectly," exclaimed Ned with a laugh. "What a gun that would be
for hunting, since most all wild beasts come out only at night."

"That was one object in making this invention," said Tom. "I only
hope I get a chance to use it now."

"I thought you were going to Africa after elephants," spoke Mr.
Swift.

"Well, I did think of it," admitted Tom, "but I haven't made any
definite plans. But come into the house, Ned, and I'll show you more
in detail how my rifle works."

Thereupon the two chums spent some time going into the mysteries of
the new weapon. Mr. Swift and Mr. Jackson were also much interested,
for, though they had seen the gun previously and had helped Tom
perfect it, they had not yet tired of discussing its merits.

Ned stayed quite late that night, and promised to come over the next
day, and watch Tom do some more shooting.

"I'll show you how to use it, too," promised the young inventor, and
he was as good as his word, initiating Ned into the mysteries of the
electric rifle, and showing him to store the charges of death-dealing
electricity in the queer-looking stock.

For a week after that Tom and Ned practiced with the terrible gun,
taking care not to have any more mishaps like the one that had
marked the first night. They were both good shots with ordinary
weapons and it was not long before they had equaled their record
with the new instrument.

It was one warm afternoon, when Tom was out in the meadow at one
side of his house, practicing with his rifle on some big boxes he
had set up for targets, that he saw an elderly man standing close to
the fence watching him. When Tom blew to pieces a particularly large
packing-case, standing a