of the boys. John was careful to tell him that Harry and George were not
wild or reckless, and that Camma would find them healthy comrades.

Shortly after noon, they were told that the first of the caves would be
found in the hill toward the right, and that the work of opening the
principal one would not be undertaken until after luncheon.

You may be sure that the boys made a hurried meal, and without waiting
for the workers to come up, they grasped their weapons, and were soon
half way up the hill, their guide, an old man, who knew the location of
the caves, being with them, to show the way.

The old man pointed to the rocky wall, and indicated where the opening
was. Ephraim had closed it effectually, for they saw the evidence of the
wall before them, where its comparatively smooth surface showed the
difference between the natural wall and the rough rocks elsewhere.

"Where is the other cave?" asked George.

"It is on the other side," he answered.

"And is that also closed?"

"Yes; just as you see this."

When the workers came up John directed them how to commence at the top,
and take out a rock at a time. He smiled as he saw how well the work had
been done, and Ephraim was gratified at the praise bestowed.

"You certainly made a first class job of ashlar work," remarked John.

"What is that?" asked Ephraim, in surprise.

"It is just this kind of masonry where the courses are irregular, and
built up from the rock just as it came from the quarry."

"I was not aware that there were different kinds of masonry. I thought
that masonry was merely the placing together of stones so they would
bind each other, and that is the way I had them do it."

"Masonry is one of the oldest of the arts. It is really the foundation
stone of architecture. The work you have done here happens to be of rock
that has a rather smooth outline, that is, the stone broke off smooth,
in the upper layers, but the large pieces near the bottom represent what
is called rubble work."

[Illustration: _Fig. 12. Types of Masonry._]

"This is very interesting to know," remarked Ephraim.

[Illustration: "_The old man pointed to the rocky wall_" [See p. 152]]

"I might add," continued John, "that when the courses are not regular it
is called _broken_ ashlar; when stones of less than one foot in breadth
are used it is called _small_ ashlar; if the wall is backed by
rubble, or inferior work it is called _bastard_ ashlar. Then every kind
of su