“Yes.”
“Is there no other outlet?”
“None except the staircase leading to the library and the other ventilator.”
“Opening on the terrace?”
“Yes.”
“Then that’s clear. The bags used to come in by the first and go out by the second.”
“But . . .”
“There’s no but about it, captain: how else would you have it happen? You see, the mistake people always make is to go looking for difficulties where there are none.”
They returned to the terrace. Don Luis took up his position near the ventilator and inspected the ground immediately around. It did not take long. Four yards away, outside the windows of the library, was the basin with the statue of a child spouting a jet of water through a shell.
Don Luis went up, examined the basin and, leaning forwards, reached the little statue, which he turned upon its axis from right to left. At the same time the pedestal described a quarter of a circle.