“I say, Turnbull, we couldn’t fight through this tube, could we?”

Sentiments beyond speech surged up in Turnbull and silenced him for a space just long enough to be painful.  Then he said with his old gaiety:  “I vote we talk a little first; I don’t want to murder the first man I have met for ten million years.”

“I know what you mean,” answered the other.  “It has been awful.  For a mortal month I have been alone with God.”

Turnbull started, and it was on the tip of his tongue to answer:  “Alone with God!  Then you do not know what loneliness is.”

But he answered, after all, in his old defiant style:  “Alone with God, were you?  And I suppose you found his Majesty’s society rather monotonous?”

“Oh, no,” said MacIan, and his voice shuddered; “it was a great deal too exciting.”

After a very long silence the voice of MacIan said:  “What do you really hate most in your place?”

“You’d think I was really mad if I told you,” answered Turnbull, bitterly.

“Then I expect it’s the same as mine,” said the other voice.

“I am sure it’s not the same as anybody’s,” said Turnbull, “for it has no rhyme or reason.  Perhaps my brain really has gone, but I detest that iron spike in the left wall more than the damned desolation or the damned cocoa.  Have you got one in your cell?”

“Not now,” replied MacIan with serenity.  “I’ve pulled it out.”

His fellow-prisoner could only repeat the words.

“I pulled it out the other day when I was off my head,” continued the tranquil Highland voice.  “It looked so unnecessary.”

“You must be ghastly strong,” said Turnbull.

“One is, when one is mad,” was the careless reply, “and it had worn a little loose in the socket.  Even now I’ve got it out I can’t discover what it was for.  But I’ve found out something a long sight funnier.”

“What do you mean?” asked Turnbull.

“I have found out where A is,” said the other.

Three weeks afterwards MacIan had managed to open up 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.