And then it was that a barrage could be laid down, and an advance attack made.  But it had to be made under somewhat adverse conditions, for gas masks must be worn.  And to leap from the trench, and stumble over No Man’s Land, under heavy fire, and discharge one’s own rifle, all the while wearing one of the canvas and rubber contraptions, was not real fighting—­at least so Jimmy said afterward.

But such it had to be, and at the signal the five Brothers leaped up with their comrades and went over the top again—­over the top of the trenches that had either been dug when the new position was taken and held, or over the top of some of the trenches wrested previously from the Germans.

There was no shouting and yelling, such as often and ordinarily preceded an attack over the top.  One can not shout in a gas mask.  But there was shouting in the hearts of the Sammies as they rushed forward to do their share in destroying the beast from the earth.

Upward and onward they rushed and then they were in the midst of the battle.  And yet not exactly in the midst, for the actual conflict was rather of longer distance than that.  Hand-to-hand fighting had not yet occurred.  But they advanced, firing as they rushed on, not in close formation, for that offered too good a target, but separated.  They would fire, rush on, drop to earth, rise again, fire and rush on.  And so it went.

And then, after an hour or two, there came a sudden shift in the wind.  It was presaged by a calm, so that the deadly chlorine gas rose straight up instead of being blown over the American lines.  And then, with a suddenness that must have been disconcerting to the Huns, the gas was blown back in their very faces.

Without doubt such fiends as devised that form of fighting were, in a way, prepared for this, and had their gas masks ready.  There were times, in the early stages of the gas war, when often whole companies of Germans would be wiped out by a sudden change in the wind, when gas was being sent over.  But the Boches learned from experience.

However, whether or not the return of their own gas worked any havoc among the Germans it did one good thing; it enabled Jimmy and his chums, as well as their comrades, to remove their own oppressive head-coverings, after a certain time had elapsed.

Once they took them off, they sniffed cautiously of the air.  There was none of the choking taint of the chlorine—­a gas which seems to dissolve the lung tissues—­the air was sweet and pure—­that is, comparatively so, though it was odorous with powder fumes.  But these were a perfume compared to chlorine.

“Oh, this is better!” cried Jimmy, as he breathed deep and filled his lungs naturally, for though there is everything to be said in favor of the gas mask when an attack is on, one can not breathe naturally in it.

“I should say so!” agreed Bob.

“Well, where do we go from here?” chanted Roger.