At first the gas had been light and volatile. It caused terrible suffering to those caught by it, but it did not hover long over any given place and a gust of wind was sufficient to drive it away.
But that was not vile enough to satisfy the infernal ingenuity of the foes of humanity. Now they were using gas that settled on the ground so that nothing but a gale would drive it away, and that lasted for hours and even for days. And then there was mustard gas, that penetrated everywhere through the clothing, through the skin, and that burned and ate up the living tissues like so much vitriol.
But the Allies were on the alert and soon found a way to avert or modify the worst consequences of the various kinds of gases. And they were forced to fight fire with fire simply in self-defence. It was a question of kill or be killed, and they were left no alternative. They asked nothing better than to fight as knightly and honorable nations always have fought and always will fight when they are left free to choose their weapons.
But whatever the methods used by the Germans, whether gas or guns or men, they were finding increasing difficulty in keeping up the momentum of their drive. Sheer force of numbers had sufficed at first to carry them forward, but now the Allies with American help coming over the sea at the rate of two hundred thousand men a month—and the finest kind of men at that—were gradually getting on even terms.
"I see the Germans had a good day yesterday," remarked Frank, as he and his comrades were at mess.
"I didn't notice it," said Bart, looking at his friend in surprise. "We drove them back and gained ground from them."
"Oh, I don't mean here," exclaimed Frank. "I mean in Paris."
Billy almost choked in surprise and alarm.
"You don't mean to say they've got to Paris?" he sputtered.
"Not by a jugful," laughed Frank. "But they're sending shells into it."