. But, as a matter of fact, it is very hard to
decipher the Mayan pictographs. So far, little but the ability to read
their calendars and numerical system is possessed by us, though we are
gradually making headway.

"Now this is the map of the district, and by the markings you can see
where I hope to find what I seek. We shall begin digging here," and he
made a small mark with a pencil on the map.

"Of course," the professor explained, "I may be wrong, and it will take
some time to discover the error if we make one. When a city is buried
thirty or forty feet deep beneath earth and great trees have grown over
it, it is not easy to dig down to it."

"How do you ever expect to find it?" asked Ned.

"Well, we will sink shafts here and there. If we find carved stones,
the remains of ancient pottery and weapons, parts of buildings or
building stones, we shall know we are on the right track," was the
answer. "And now that I have shown you the map, and explained how
valuable it is, I will put it away again. We shall begin our
excavations in the morning."

"At what point?" asked Tom.

"At a point I shall indicate after a further consultation of the map.
I must see the configuration of the country by daylight to decide. And
now let's get some rest. We have had a hard day."

The two tents housing the four white members of the Bumper party were
close together, and it was decided that the night would be divided into
four watches, to guard against possible treachery on the part of the
Beecher crowd.

"It seems an unkind precaution to take against a fellow scientist,"
said Professor Bumper, "but I can not afford to take chances after what
has occurred."

The others agreed with him, and though standing guard was not pleasant
it was done. However the night passed without incident, and then came
morning and the excitement of getting breakfast, over which the Indians
made merry. They did not like the cold and darkness, and always
welcomed the sun, no matter how hot.

"And now," cried Tom, when the meal was over, "let us begin the work
that has brought us here."

"Yes," agreed Professor Bumper, "I will consult the map, and start the
diggers where I think the city lies, far below the surface. Now,
gentlemen, if you will give me your attention----"

He was seeking through his outer coat pockets, after an ineffectual
search in the inner one. A strange look came over his face.

"What's the matter?" asked Tom.

"