"What is absurd?" said the professor quietly.

"Why, to see him walking on like that. Ill! Invalid! He is an
impostor."

The professor smiled.

"I say, is it safe to let him go on like that?"

"So long as he feels no fear. See how confident he is!" said Mr
Preston.

Just then Lawrence stopped for the others to overtake him.

"Have you noticed what beautiful white stone this is, Mr Preston?" he
said.

He pointed down at the path they were on, for every here and there the
rock was worn smooth and shiny by the action of the air and water,
perhaps, too, by the footsteps of men for thousands of years, and was
almost as white as snow.

"Yes," said the professor, "I have been making a mental note of it, and
wishing I had a geologist's hammer. You know what it is, I suppose?"

"White stone, of course," said Mr Burne.

"Fine white marble," said the professor.

"Nonsense, sir! What! in quantities like this?"

"To be sure."

"But it would be worth a large fortune in London."

"Exactly, and it is worth next to nothing here, because it could not be
got down to the sea-shore, and the carriage would be enormous."

"What a pity!" exclaimed the old lawyer. "Dear me! Fine white marble!
So it is. What a company one might get up. The Asia Minor Major Marble
Quarry Company--eh, Preston?"

"Yes, in hundred-pound shares that would be worth nothing."

"Humph! I suppose not. Well, never mind. I'd rather have a chicken
pie and a loaf of bread now than all the marble in the universe. Let's
get on."

Their progress was slow, for in spite of all that Yussuf had said they
had to exercise a great deal of care, especially as the narrow track
rose higher and higher, till they were at a dizzy height above the
little stream, whose source they passed just as the sun was getting low;
and then their way lay between two steep cliffs; and next round a sunny
slope that was dotted with huge walnut-trees, the soil being; evidently
deep and moist consequent upon a spring that crossed their path.

The trees were of great girth, but not lofty, and a peculiarity about
them was that they were ill-grown, and gnarled and knotted in a way that
made them seem as if they were diseased. For every now and then one of
them displayed a huge lump or boss, such as is sometimes seen upon elms
at home.

"There's another little fortune there, Burne," said the professor
quietly.

"Nonsense, sir! There isn't a tree in the lot out of whi