"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." "I wanted to obtain a lamp of a certain pattern," continued Carrados. "It seemed to me that the simplest explanation would be to say that I wanted it for a motor car. Naturally I went to Long Acre. At the first shop I said: 'Wasn't it here that a friend of mine, an Indian gentleman, recently had a lamp made with a green glass that was nearly five inches across?' No, it was not there but they could make me one. At the next shop the same; at the third, and fourth, and so on. Finally my persistence was rewarded. I found the place where the lamp had been made, and at the cost of ordering another I obtained all the details I wanted. It was news to them, the shopman informed me, that in some parts of India green was the danger colour and therefore tail lamps had to show a green light. The incident made some impression on him and he would be able to identify their customer--who paid in advance and gave no address--among a thousand of his countrymen. Do I succeed in interesting you, Mr Drishna?" "Do you?" replied Drishna, with a languid yawn. "Do I look interested?" "You must make allowance for my unfortunate blindness," apologized Carrados, with grim irony. "Blindness!" exclaimed Drishna, dropping his affectation of unconcern as though electrified by the word, "do you mean--really blind--that you do not see me?" "Alas, no," admitted Carrados. The Indian withdrew his right hand from his coat pocket and with a tragic gesture flung a heavy revolver down on the table between them.