ed that Robert should succeed him.
"There will be envious and grasping hands," he said, "held out--but
you are strong and wise, and the people will be content to be ruled by
you," and then he showed him a paper that made him a prince in title,
and that gave him the Dukedom on his own death.

Now there lived in the Duke's house a wise and learned man named
Paul, an alchemist, who knew the courses of the stars and the virtues
of plants, and many other secret things; and the Duke delighted much
in his conversation, which was ingenious and learned. But Robert heard
him vacantly, thinking that such studies were fit only for children.
And Paul being old and gentle, loved not Robert, but held that the
Duke trusted him overmuch. And one night, when Robert and other lords
were sitting with the Duke, Paul being present, the talk turned on the
virtues of gems; and Paul, as if making an effort that he had long
prepared for, told the Duke of a curious liquor, an _aqua fortis_,
that he had distilled, which was a marvellous thing to test the worth
of gems, and would tell the true from the false; and the Duke bade him
bring the liquor and show him how the spirit worked. And it seemed to
Robert that, as Paul spoke, a shadowy hand came from the darkness and
clutched at his heart, enveloping him in blackness, so that he sate in
a cold dream. And Paul went out, and presently returned bringing a
small phial of gold--for the liquor, he said, would eat its way
through any baser metal--and in the other hand a little dish of gems.
Some of them, he said, were true gems, others of them less precious,
and others naught but sparkling glass; and he poured a drop on each;
the true gems sparkled unhurt in the clear liquid, the less precious
threw off little flakes of impurity, and the glass hissed and melted
in the potent venom. And Robert, contrary to his wont, came and stood,
sick at heart, feeling the old man's eyes fixed on him with a steady
gaze. At last Paul said, "The Prince Robert"--for the Duke had told
the lords of the honour he had given him--"seems to wonder more than
his wont at these simple toys and tricks; shall not the Duke let us
test the great ruby, that its worth may be the better proven? perhaps
too it has some small impurity to be purged away, and will shine more
bravely, like a noble heart under affliction." And the Duke said,
"Yes, let the ruby be brought."

So the lord that had the charge of the Duke's jewels brought a casket,