“By Gad, you are right, Max!” he exclaimed, peeping through the curtains.  “There is a man inside.”

“Mr. Drishna,” announced Parkinson a minute later.

The visitor came into the room with leisurely self-possession that might have been real or a desperate assumption.  He was a slightly built young man of about twenty-five, with black hair and eyes, a small, carefully trained moustache, and a dark olive skin.  His physiognomy was not displeasing, but his expression had a harsh and supercilious tinge.  In attire he erred towards the immaculately spruce.

“Mr. Carrados?” he said inquiringly.

Carrados, who had risen, bowed slightly without offering his hand.

“This gentleman,” he said, indicating his friend, “is Mr. Carlyle, the celebrated private detective.”

The Indian shot a very sharp glance at the object of this description.  Then he sat down.

“You wrote me a letter, Mr. Carrados,” he remarked, in English that scarcely betrayed any foreign origin, “a rather curious letter, I may say.  You asked me about an ancient inscription.  I know nothing of antiquities; but I thought, as you had sent, that it would be more courteous if I came and explained this to you.”

“That was the object of my letter,” replied Carrados.

“You wished to see me?” said Drishna, unable to stand the ordeal of the silence that Carrados imposed after his remark.

“When you left Miss Chubb’s house you left a ruler behind.”  One lay on the desk by Carrados and he took it up as he spoke.

“I don’t understand what you are talking about,” said Drishna guardedly.  “You are making some mistake.”

“The ruler was marked at four and seven-eighths inches—­the measure of the glass of the signal lamp outside.”

The unfortunate young man was unable to repress a start.  His face lost its healthy tone.  Then, with a sudden impulse, he made a step forward and snatched the object from Carrados’s hand.

“If it is mine I have a right to it,” he exclaimed, snapping the ruler in two and throwing it on to the back of the blazing fire.  “It is nothing.”

“Pardon me, I did not say that the one you have so impetuously disposed of was yours.  As a matter of fact, it was mine.  Yours is—­elsewhere.”

“Wherever it is you have no right to it if it is mine,” panted Drishna, with rising excitement.  “You are a thief, Mr. Carrados.  I will not stay any longer here.”

He jumped up and turned towards the door.  Carlyle made a step forward, but the precaution was unnecessary.

“One moment, Mr. Drishna,” interposed Carrados, in his smoothest tones.  “It is a pity, after you have come so far, to leave without hearing of my investigations in the neighbourhood of Shaftesbury Avenue.”

Drishna sat down again.

“As you like,” he muttered.  “It does not interest me.”