t it at the hospital," he thought, "but I entirely
forgot it."

He drew it out and looked at it. He now saw that the lead cylinder
enclosed a glass vial carefully corked and sealed. The bottle was
wrapped in flannel. Jack could not withstand the temptation of pulling
it out and looking at it. He hardly knew what he had expected to see,
but he was distinctly disappointed, as was Tom, to find that the
carefully protected vial contained nothing more than some dark, almost
black, stuff that looked like sand. In it were particles that
glittered like mica.

"Pshaw!" he exclaimed in a disappointed tone, "nothing but a bottle
full of sand. Wonder why in the world that fellow carried trash like
that so carefully wrapped up for?"

The solution of the question, which was near at hand, was to have an
important bearing on the lives of the Boy Inventors, and that in the
immediate future.

CHAPTER XIII.

THE LEADEN TUBE.

The following day, while they were experimenting and practicing with
the radio telephone, the boys received word that the man in the
hospital was conscious and wished to see them, if possible.

"Perhaps now we shall get some explanation of that queer tubeful of
sand," said Jack, as he hung up the telephone receiver, having
informed the physician that they would be at the hospital shortly.

"It's certainly a queer sort of thing for a man to carry about--a
glass vial full of black grit so carefully protected, unless he is
crazy or something," commented Tom.

"I think that there is some explanation back of all this," said Jack,
"and for my part the sooner we get to the hospital, the better I shall
be pleased. The man told the doctor he was a miner and his name is
Zeb Cummings. Perhaps that sand is gold-bearing or something like
that."

"That might be the case," agreed Tom.

The boys decided to take out the electric car. It was in perfect
running order and the indicator showed that there was plenty of
electricity in storage for the start. They told Mr. Chadwick where
they were going and then rolled out of the High Towers gates onto the
broad, smooth road bordered with pleasant green elms.

They bowled along smoothly and silently with the car working as
perfectly as delicate clockwork. They had gone about a mile from the
house and were on a steep grade which the car took as easily as if it
had been going down hill, when their attention was attracted by a
sudden shout from the vicinity.

Jack bro