communications which made his meaning plain. By that time the two
captives had fully discovered and demonstrated that weakness in
the very nature of modern machinery to which we have already
referred. The very fact that they were isolated from all
companions meant that they were free from all spies, and as there
were no gaolers to be bribed, so there were none to be baffled.
Machinery brought them their cocoa and cleaned their cells; that
machinery was as helpless as it was pitiless. A little patient
violence, conducted day after day amid constant mutual
suggestion, opened an irregular hole in the wall, large enough to
let in a small man, in the exact place where there had been
before the tiny ventilation holes. Turnbull tumbled somehow into
MacIan's apartment, and his first glance found out that the iron
spike was indeed plucked from its socket, and left, moreover,
another ragged hole into some hollow place behind. But for this
MacIan's cell was the duplicate of Turnbull's--a long oblong
ending in a wedge and lined with cold and lustrous tiles. The
small hole from which the peg had been displaced was in that
short oblique wall at the end nearest to Turnbull's. That
individual looked at it with a puzzled face.

"What is in there?" he asked.

MacIan answered briefly: "Another cell."

"But where can the door of it be?" said his companion, even more
puzzled; "the doors of our cells are at the other end."

"It has no door," said Evan.