Page:The Clue of the Twisted Candle (1916).djvu/236

experience and I have discovered the impossibility of bringing an architect to one's way of thinking even in so commonplace a matter as the position of a scullery. It would be much more difficult to induce him to construct a house with double walls and secret chambers."

T. X. waited patiently.

"There is a possibility, of course," said Lexman slowly, "that the steel latch may have been raised by somebody outside by some ingenious magnetic arrangement and lowered in a similar manner."

"I have thought about it," said T. X. triumphantly, "and I have made the most elaborate tests only this morning. It is quite impossible to raise the steel latch because once it is dropped it cannot be raised again except by means of the knob, the pulling of which releases the catch which holds the bar securely in its place. Try another one, John."

John Lexman threw back his head in a noiseless laugh.

"Why I should be helping you to discover the