"But," exclaimed Ricardo, "those pearls were of great value, and I have heard at a trial expert evidence given by pearl merchants. All agree that the pearls of great value are known; so, when they come upon the market----"
"That is true," Hanaud interrupted imperturbably. "But how are they known?"
"By their weight," said Mr. Ricardo.
"Exactly," replied Hanaud. "But did you not also hear at this trial of yours that pearls can be peeled like an onion? No? It is true. Remove a skin, two skins, the weight is altered, the pearl is a trifle smaller. It has lost a little of its value, yes--but you can no longer identify it as the so-and-so pearl which belonged to this or that sultan, was stolen by the vizier, bought by Messrs. Lustre and Steinopolis, of Hatton Garden, and subsequently sold to the wealthy Mrs. Blumenstein. No, your pearl has vanished altogether. There is a new pearl which can be traded." He looked at Ricardo. "Who shall say that those pearls are not already in one of the queer little back streets of Amsterdam, undergoing their transformation?"
Mr. Ricardo was not persuaded because he would not be. "I have some experience in these matters," he said loftily to Hanaud. "I am sure that we shall lay our hands upon the criminals. We have never failed."
Hanaud grinned from ear to ear. The only experience which Mr. Ricardo had ever had was gained on the shores of Geneva and at Aix under Hanaud's tuition. But Hanaud did not argue, and there the matter rested.
The days flew by. It was London's play-time. The green and gold of early summer deepened and darkened; wondrous warm nights under England's pale blue sky, when the streets rang with the joyous feet of youth, led in clear dawns and lovely glowing days. Hanaud made acquaintance with the wooded reaches of the Thames; Joan Carew sang "Louise" at Covent Garden with notable success; and the affair of the Semiramis Hotel, in the minds of the few who remembered it, was already added to the long list of unfathomed mysteries.
But towards the end of May there occurred a startling development. Joan Carew wrote to Mr. Ricardo that she would call upon him in the afternoon, and she begged him to secure the presence of Hanaud. She came as the clock struck; she was pale and agitated; and in the room where Calladine had first told the story of her visit she told another story which, to Mr. Ricardo's thinking, was yet more strange and--yes--yet more suspicious.
"It has been going on for some time," she began. "I thought of coming to you at once. Then I wondered whether, if I waited--oh, you'll never believe me!"
"Let us hear!" said Hanaud patiently.