"I do not see how," replied Gratz.

"What do you gain by it?" asked the Sepoy.

"I cannot tell that in advance; possibly nothing," replied Gratz.

"That is likely," replied the Sepoy quietly.

"We shall see," exclaimed the detective. "I am working out a theory; I need the assistance of all concerned."

"Look at me!" exclaimed the Sepoy abruptly. "I will credit you with being something of a physiognomist. Do you see any evidences of determination in my face?"

"And if I do?" queried Gratz.

"Only this," was the reply: "No matter what your object may be, I will oppose it with all the resolution and dexterity at my command, if you conduct your inquiries as you contemplate."

In reply Gratz offered an exasperating shrug of the shoulders.

"There is no mystery to be solved," he said. "I have no further facts to discover; I know that you have managed to secure three separate bags of coin from Raikes, and I am aware of your process."

"If you know all this," replied the other with curious calmness, "why do you----"

The question was interrupted by the sound of approaching footsteps.

"Now!" exclaimed Gratz, as if with sudden determination, "I will try to grant your request in part. Retire into your bedchamber, leave the door open, and listen.

"I will place Raikes and his nephew where they cannot see you, but I will sit here where I can note your slightest move."

The Sepoy arose hastily and entered the bedchamber, seating himself according to the direction of the detective.

At that moment there was a knock upon the door.

In answer to the salutation of the detective Raikes and his nephew entered.

Seating themselves in the chairs indicated, they awaited with intense curiosity the proceedings of this enigmatical man.

Noting the alert questioning in the eyes of the young man, and the half-awakened inquiry in the sordid countenance of Raikes, Gratz, in order to prevent the intrusion of any disturbing remark upon his present purpose, said impressively:

"I must ask you both to listen without interruption. When I want you to speak I will question you"; and fastening his strange eyes upon the blinking Raikes, he added: "Now we will proceed.

"You have lost four bags of coin."

"Three!" corrected Raikes, despite his instructions to silence.

"Pardon me," continued Gratz, "and please do not interrupt. I said four--and here is the fourth," and he pointed to the bag upon the table.

The miser's jaw dropped helplessly, and he stared at the bag with a superstitious terror.

"But," continued Gratz, "what seems so incredible to you is merely the logical outcome of a cunningly established sequence," and the speaker shot an incredibly quick glance at the silent figure in the adjoining room.

"Now attend me closely.

"During the last few evenings you have heard some very curious narratives."

Raikes nodded with gloomy corroboration.

"A series of well-arranged events have introduced a startling episode--the substitution of pebbles for diamonds."

Again Raikes nodded.

"At this point in the narrative the first instalment concludes. Am I right?"

"Yes," answered Raikes.

"Then," continued Gratz, "you went directly to your room; you retired.

In the morning you are prompted, with more than your usual eagerness, to open your private safe."

"Right!" exclaimed Raikes in indorsement of this relentless resume.

"You find the locks undisturbed; the contents apparently as you left them on retiring. Some difference in the conformity of one of the bags urges a nearer examination. You discover that this indicates a difference in the contents. You grasp it; it comes away in your hands with startling lightness. You discharge its deposit upon the table--a shower of coals follows."

"Yes, yes!" stammered Raikes with impatient eagerness.

"Well, you are convinced, by an examination of the fastenings of the door, an inspection of the window, that no human being could have effected an entrance from either direction.

"The next evening is a repetition of the history of the night before.

"The strange Indian narrative, another gem to examine--an additional loss on the succeeding morning."

Raikes nodded savagely.

"On the following night the same unhappy series of events occur, followed by the loss of the third bag."

"But why all this again?" inquired Raikes.

"That concerns me," exclaimed the detective with another rapid glance at the undemonstrative figure in the next room. "You must follow my instructions or you will conclude as badly as you have begun. Now,"

continued Gratz, "it is incredible to me that, with the astuteness with which you are credited, that having such a good standpoint to begin with, you did not proceed upon that basis."

"I?" questioned the astonished Raikes. "What standpoint had I?"

"Elimination," replied Gratz.

"Several puzzling possibilities were retired permanently.

"Recall the details as we have enumerated them: An impossible door; the window equally out of the question; the substitution of the coals for the coin.

"It is very simple. The outside agency unfeasible, we must look within.

There is but one conclusion----"