For quite three minutes there was silence. Salt was thinking, not idly, but estimating exactly the effect of what had happened. Miss Lisle was waiting, with somewhat rare perception, until he was ready to continue.
"Sooner or later something of the sort was bound to come," he summed up quietly, without a trace of discomfiture. "It is only the personality that is surprising. His interests are identical with ours; he has everything to gain by our success. Why; why on earth?"
"I think that I can explain that in three words," suggested Miss Lisle. "Velma St Saint."
Salt looked enquiringly. He had forgotten the Hon. Freddy's deity for the moment.
"Of the Vivarium," added Irene.
"Oh, the lady who hangs by her toes," he remarked with enlightenment.
"'The World's Greatest Inverted Cantatrice'!" quoted Miss Lisle. "That is her celebrated 'Upside Down' song that the organ is playing in the street below. A few years ago she got a week's engagement at the Elysium at a salary of eighty pounds. She calculated from that that she could afford to spend four thousand a year, and although all theatrical incomes have steadily declined ever since until she only gets ten pounds a week now, she has never been able to make any difference in her style of living.... Of course there is a deficit to be made up."
"It is just as well. If it had not been Tantroy it would have been some one abler. Now what has he done, what has he learned?"
"Duplicate keys of this door and of my desk have been made. The lock of the cipher typewriter case is not of an elaborate pattern, and any one bringing a quantity of keys of the right size would probably find one to answer. I don't think that either your desk or the safe has been opened; certainly not since I began to notice. The papers to which he would have access are consequently not highly important."
"Letters?" suggested Salt. "For instance, my letters lying here until you forwarded them. There is a post in at eight o'clock in the morning; others after you have left up to ten at night. There would be every opportunity for abstracting some, opening them at leisure, and then dropping them into the letter-box again a little later."