his conversation. I also want
to know who was in the room with Kara when Gathercole went in."

"H'm," said John Lexman.

"Even if I found who the third person was, I am still puzzled as to how
they got out and fastened the heavy latch behind them. Now in the old
days, Lexman," he said good humouredly, "you would have made a fine
mystery story out of this. How would you have made your man escape?"

Lexman thought for a while.

"Have you examined the safe!" he asked.

"Yes," said the other.

"Was there very much in it?"

T. X. looked at him in astonishment.

"Just the ordinary books and things. Why do you ask?"

"Suppose there were two doors to that safe, one on the outside of the
room and one on the inside, would it be possible to pass through the
safe and go down the wall?"

"I have thought of that," said T. X.

"Of course," said Lexman, leaning back and toying with a salt-spoon,
"in writing a story where one hasn't got to deal with the absolute
possibilities, one could always have made Kara have a safe of that
character in order to make his escape in the event of danger. He might
keep a rope ladder stored inside, open the back door, throw out his
ladder to a friend and by some trick arrangement could detach the ladder
and allow the door to swing to again."

"A very ingenious idea," said T. X., "but unfortunately it doesn't work
in this case. I have seen the makers of the safe and there is nothing
very eccentric about it except the fact that it is mounted as it is. Can
you offer another suggestion?"

John Lexman thought again.

"I will not suggest trap doors, or secret panels or anything so banal,"
he said, "nor mysterious springs in the wall which, when touched, reveal
secret staircases."

He smiled slightly.

"In my early days, I must confess, I was rather keen upon that sort
of thing, but age has brought 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 mor