“Ciel, we are in zee luck!” exclaimed de Garros, after a brief examination, “the chiens only smashed a spark plug. I soon fix ’im and zen once more we start.”
The repair kit contained the necessary plug, which he quickly replaced. Then the journey through the night, which had already proved so eventful, was renewed. But now Jack felt a fresh alarm. How would they be able to tell at Louvain that it was a French and not a German aeroplane hovering above them.
He put the question to de Garros.
“Zat is easy. I ’ave on zee side of zee machine a set of four electric lights. Two are red, one is green, one is white. Zat is zee secret night signal of zee French machines.”
“But suppose the Germans should find out your code?” asked Jack.
“Eet is changed every night. Sometimes two green, one white, one red—many combinations are possible.”
“By Jove, I never thought of that!” exclaimed Jack, struck by the simplicity of the idea, and relieved at the thought that there would be no danger of being attacked by mistake.
Half an hour later they landed at a sort of fair ground in Louvain after answering all challenges satisfactorily. The Germans were not yet at the gate of the city. But they were near at hand and the place was wrapped in darkness. However, on account of de Garros’ rank, they obtained an escort to the hotel.
Tired from the excitement and nervous strain, Jack went to bed, sighing with relief at the thought that all was so promising.
In about an hour or so he awakened from a deep sleep. The night was sultry, and there was a strange calmness in the atmosphere seemingly weighed with grave and impending events.