“Merrick!” repeated Mr. Thornton, turning to Mr. Whitney in surprise.  “Is Mr. Merrick a detective?”

“He is.  I did not introduce him as such, for the reason that in a case of this kind he usually prefers to make his first visit incognito if possible.”

“Very well; you have taken the responsibility in this matter.  You understand, of course, Mr. Whitney, that we want no amateur work in a case like this.”

“Mr. Merrick is no amateur,” said the attorney, quietly; “he is one of the most trusted and one of the surest men on the force.”

“Before we go any farther,” interposed Ralph Mainwaring, “I suggest that we ascertain whether or not there has been a robbery.  We can at least satisfy ourselves on that point.”

“Acting on your suggestion, we will examine the safe,” said Mr. Whitney; “though I, for one, am not inclined to think there has been any robbery.  Without a knowledge of the combination, the safe could not be opened unless force were employed; and it certainly bears no evidence of having been tampered with.”

“Proceed with your investigation, Mr. Whitney,” said the quiet voice of the detective, who had entered unobserved from the smoking-room; “unless I am greatly mistaken, the person we are after is some one pretty familiar with various ‘combinations’ in these apartments.”

There was a general expression of surprise, and all turned towards Mr. Merrick for an explanation, but a glance at his impassive face convinced them that questions would be useless.

With a few swift turns the secretary unlocked the safe and the ponderous doors swung open, showing books and papers in their accustomed places.  Everything appeared in perfect order; but as the attorney began a rapid examination of the interior, he suddenly uttered a sharp exclamation, while, as he continued his search, his manner betrayed considerable excitement.

“Anything wrong, Mr. Whitney? anything missing?” queried Ralph Mainwaring.

“Everything is missing!” the other exclaimed, after a moment’s pause, turning around with a pale face and holding in his hand an empty cash box; “there is absolutely nothing left but an old cheque-book, a few drafts, and some other papers of no value whatever except to Hugh Mainwaring himself!”

Half a score of questions were instantly raised:  “Was there a large amount of money in the safe?” “Did it contain anything of great value?”

Scott, standing silently in the background, seemed to see again the brilliant gems flashing in the sunlight, as he had seen them in his search on the preceding day, but he said nothing.

“There was a considerable amount of cash,” the attorney was saying.  “Mr. Mainwaring deposited a large sum there when he last came out from the city, and,” he added more slowly, “the old family jewels were kept in the safe.”

“The Mainwaring jewels!” echoed both the Englishmen.  “Impossible! incredible!” While Ralph Mainwaring exclaimed, “Why, they were worth a fortune several times over in themselves!”