he had done anything extraordinary.

When Barbara was finally alone in her room she drew out of her pocket
the slip of yellow paper, spread it on her lap and regarded it intently.

"'The span of a minute is sixty seconds,'" she read. "What can that
mean?"

She got up and paced the floor thinking deeply, trying to solve the
meaning. She at last went to a window and spread the paper on the pane
for the purpose of getting a better light on it. Her gaze, at first
careless, suddenly became keen. All at once she whirled about and dashed
from the room.

"Girls, I have it!" she screamed, bursting in on the others, who were in
Ruth's room. "I've solved the mystery! I've found the key! We must get
Mr. Stevens! We mustn't lose a minute! Everything's at stake!"

"What is it, Bab? Are you certain?" demanded Grace, springing to her
feet.

"Oh, I can't tell you now! Let's get Mr. Stevens, can't we?"

"Mr. A. Bubble!" cried Ruth, and flew from the room.

The girls rushed pell-mell for the car, dragging Miss Stuart with them,
none knowing what Bab had in mind, but all eager and excited. Ruth drove
at top speed, and the girls burst in on Bob Stevens whom they found in
his shop.

"See this!" cried Bab, holding the bit of paper out to the young man.
"Put it against the window." He did so wonderingly, then turned and
looked at the girls. "What did you see?" demanded Bab impatiently.

Bob had seen a line drawn from the top of a toadstool extending to the
right. At the end of the line was the sign "60".

"What do those little marks after the sixty mean?" demanded Bab.

"On building plans they would mean inches. Expressing time, they would
indicate seconds."

"You have it! If we face the woods and start to measure from the top of
the 'toadstool,' that undoubtedly represents the mound under which lies
the big chief, and measure off 'sixty seconds' which means sixty inches,
or five feet, we'll find the treasure."

No one stopped to question the probability of Barbara's deductions. Bob
summoned a man who worked for him, sent a boy to get two more from
Treasureholme, and, taking picks, shovels, and a coil of rope, drove off
with the girls in Mr. A. Bubble as fast as they could go to the Indian
burying ground. It was nearly dark when they reached there and sprang
from the car, neither Bab nor Bob waiting for it to come to a full stop.

"William, bring me something I can drive in here for a marker," Bob
called to his man who was hu