“Yes,” I answered, producing my spoils in triumph.

“Oh, how dreadful!” she cried, drawing back.  “Do you think they’re real?  Are you sure he hasn’t cheated you?”

“Certain of it,” I replied, examining them.  “No one can take me in, in the matter of diamonds.  Why on earth should you doubt them?”

“Because I’ve been talking to Mrs. O’Hagan, at the hotel, and she says there’s a well-known trick just like that—­she’s read of it in a book.  A swindler has two sets—­one real, one false; and he makes you buy the false ones by showing you the real, and pretending he sells them as a special favour.”

“You needn’t be alarmed,” I answered.  “I am a judge of diamonds.”

“I shan’t be satisfied,” Amelia murmured, “till Charles has seen them.”

We went up to the hotel.  For the first time in her life I saw Amelia really nervous as I handed the stones to Charles to examine.  Her doubt was contagious.  I half feared, myself, he might break out into a deep monosyllabic interjection, losing his temper in haste, as he often does when things go wrong.  But he looked at them with a smile, while I told him the price.

“Eight hundred pounds less than their value,” he answered, well satisfied.

“You have no doubt of their reality?” I asked.

“Not the slightest,” he replied, gazing at them.  “They are genuine stones, precisely the same in quality and type as Amelia’s necklet.”

Amelia drew a sigh of relief.  “I’ll go upstairs,” she said slowly, “and bring down my own for you both to compare with them.”

One minute later she rushed down again, breathless.  Amelia is far from slim, and I never before knew her exert herself so actively.

“Charles, Charles!” she cried, “do you know what dreadful thing has happened?  Two of my own stones are gone.  He’s stolen a couple of diamonds from my necklet, and sold them back to me.”

She held out the rivière.  It was all too true.  Two gems were missing—­and these two just fitted the empty places!

A light broke in upon me.  I clapped my hand to my head.  “By Jove,” I exclaimed, “the little curate is—­Colonel Clay!”

Charles clapped his own hand to his brow in turn.  “And Jessie,” he cried, “White Heather—­that innocent little Scotchwoman!  I often detected a familiar ring in her voice, in spite of the charming Highland accent.  Jessie is—­Madame Picardet!”

We had absolutely no evidence; but, like the Commissary at Nice, we felt instinctively sure of it.

Sir Charles was determined to catch the rogue.  This second deception put him on his mettle.  “The worst of the man is,” he said, “he has a method.  He doesn’t go out of his way to cheat us; he makes us go out of ours to be cheated.  He lays a trap, and we tumble headlong into it.  To-morrow, Sey, we must follow him on to Paris.”