He was still talking when Recklow arrived at his side from the ravine below, tore off his gas-mask, and put on a peculiar helmet.  Then, taking the transmitter into his right hand:  “Do you get them?” he demanded of his companion, an American lieutenant.

“No trouble, sir.  No need to raise one’s voice.  They hear quite perfectly, and one hears them, sir.”

Then Recklow spoke to the three airplanes circling like hawks in the sky overhead; and one by one the observers in each machine replied in English, their voices easily audible.

“I want Zell watched from the air,” said Recklow.  “The Boche have an underground tunnel beginning near Zell, continuing under Mount Terrible to the French frontier.

“I want the Zell end of the tunnel kept under observation.

“Send our planes in from Belfort, Toul, Nancy, and Verdun.

“And keep me informed whether railroad trains, camions, or cavalry come out.  And whether indeed any living thing emerges from the end of the tunnel near Zell.

“Because we are gassing the tunnel from this ravine.  And I think we’ve got the dirty vermin wholesale!”

At sundown a plane appeared overhead and talked to Recklow: 

“One railroad train came out.  But it was manned by dead men, I think, because it crashed into the rear masonry of the station and was smashed.”

“Nothing else, living or dead, came out?”

“Nothing, sir.  There is wild excitement at Zell.  Troops at the tunnel’s mouth wear gas-masks.  We bombed them and raked them.  The Boche planes took the air but two crashed and the rest turned east.”

“You saw no living creature escape from the Zell end of the tunnel?”

“Not a soul, sir.”

Recklow turned to the group of officers around him: 

“I guess they’re done for,” he said.  “That fumigation cleaned out the vermin.  But keep the tunnel pumped full of gas....  Au revoir, messieurs!”

On his way back across Mount Terrible he encountered a relay of Alpinists bringing fresh gas. tanks; and he laughed and saluted their officers.  “This poor old world needs a de-lousing,” he said.  “Foch will attend to it up here on top of the world.  See that you gentlemen, purge her interior!”

The nurse opened the door and looked into the garden.  Then she closed the door, gently, and went back into the house.

For she had seen a slim girl with short yellow hair curling all over her head, and that head was resting on a young man’s shoulder.

It seemed unnecessary, too, because there were two steamer chairs under the rose arbor, side by side, and pillows sufficient for each.

And why a slim young girl should prefer to pillow her curly, yellow head upon the shoulder of a rather gaunt young man—­the shoulder, presumably, being bony and uncomfortable—­she alone could explain perhaps.

The young man did not appear to be inconvenienced.  He caressed her hair while he spoke: