Presently he was joined by a slim young officer similarly disguised.  It was the Commander of “A” Company.  Wagstaffe placed his head close to Bobby’s left ear, and shouted through the cloth—­

“We shan’t feel this gas much.  They’re letting it off higher up the line.  Look!”

Bobby, laboriously inhaling the tainted air inside his helmet,—­being preserved from a gas attack is only one degree less unpleasant than being gassed,—­turned his goggles northward.

In the dim light of the breaking day he could discern a greenish-yellow cloud rolling across from the Boche trenches on his left.

“Will they attack?” he bellowed.

Wagstaffe nodded his head, and then cautiously unbuttoned his collar and rolled up the front of his helmet.  Then, after delicately sampling the atmosphere by a cautious sniff, he removed his helmet altogether.  Bobby followed his example.  The air was not by any means so pure as might have been desired, but it was infinitely preferable to that inside a gas-helmet.

“Nothing to signify,” pronounced Wagstaffe.  “We’re only getting the edge of it.  Sergeant, pass down that men may roll up their helmets, but must keep them on their heads.  Now, Bobby, things are getting interesting.  Will they attack, or will they not?”

“What do you think?” asked Bobby.

“They are certainly going to attack farther north.  The Boche does not waste gas as a rule—­not this sort of gas!  And I think he’ll attack here too.  The only reason why he has not switched on our anaesthetic is that the wind isn’t quite right for this bit of the line.  I think it is going to be a general push.  Bobby, have a look through this sniper’s loophole.  Can you see any bayonets twinkling in the Boche trenches?”

Bobby applied an eye to the loophole.

“Yes,” he said, “I can see them.  Those trenches must be packed with men.”

“Absolutely stiff with them,” agreed Wagstaffe, getting out his revolver.  “We shall be in for it presently.  Are your fellows all ready, Bobby?”

The youthful Captain ran his eye along the trench, where his Company, with magazines loaded and bayonets fixed, were grimly awaiting the onset.  There had been an onset similar to this, with the same green, nauseous accompaniment, in precisely the same spot eight months before, which had broken the line and penetrated for four miles.  There it had been stayed by a forlorn hope of cooks, brakesmen, and officers’ servants, and disaster had been most gloriously retrieved.  What was going to happen this time?  One thing was certain:  the day of stink-pots was over.

“When do you think they’ll attack?” shouted Bobby to Wagstaffe, battling against the noise of bursting shells.

“Quite soon—­in a minute or two.  Their guns will stop directly—­to lift their sights and set up a barrage behind us.  Then, perhaps the Boche will step over his parapet.  Perhaps not!”