innocently asked a young American, who had lately joined.
"No," laughed Tom. "We call the German observation balloons 'sausages.' And sometimes, when they send up too many of them, to get observations and spoil our plans for an offensive, we raid them. It's difficult work, for we have to take them unawares or they'll haul them down. We generally go in a double squadron for this work. The heavy Caudrons screen the movements of the little Nieuports, and these latter, each with a single man in it, fire phosphorus bullets at the gas bags of the German sausages.
"These phosphorus bullets get red hot from the friction of the air, and set the gas envelope aglow. That starts the hydrogen gas to going and—good-night to Mr. Fritz unless he can drop in his parachute. A raid on the sausages is full of excitement, but it means a lot of preparation, for if there has any rain or dew fallen in the night the gas bags will be so damp that they can't be set on fire, and the raid is off"
"Say, you know a lot about this business, don't you?" asked the young fellow who had put the question.
"Nobody knows a lot about it," replied Jack. "Just as soon as he does he gets killed, or some-