“Then he might have tried to make us,” answered Harry, also in a whisper.  “Did you notice anything queer about him ?”

“Why, no —­”

“You have your way lost!’ Would any Englishman say that, Dick?  And wouldn’t a German?  You’ve studied German.  Translate ’You’ve lost your way’ into German.  ‘Du hast dein weg —­’ See?  He was a German spy!”

“Oh, Harry!  I believe you’re right!  But why didn’t we —­”

“Try to arrest him?  There may have been a dozen others there, too.  And there was the driver.  We wouldn’t have had a chance.  Besides, if he thinks we don’t suspect, we may be able to get some valuable information later.  I think —­”

“What?”

“I’d better not say now.  But remember this —­ we’ve got to look out for this driver.  I think he’ll take us straight to Ealing now.  When we get to the barracks you stay in the cab —­ we’ll pretend we may have to go back with him.”

“I see,” said Dick, thrilling with the excitement of this first taste of real war.

Harry was right.  The driver’s purpose in making such a long detour, whatever it was, had been accomplished.  And now he plainly did his best to make up for lost time.  He drove fast and well, and in a comparatively short time both the scouts could see that they were on the right track.

“You watch one side.  I’ll take the other,” said Harry.  “We’ve got to be able to find our way back to that house.”

This watchfulness confirmed Harry’s suspicions concerning the driver, because he made two or three circuits that could have no other purpose than to make it hard to follow his course.

At Ealing he and Dick carried out their plan exactly.  Dick stayed with the cab, outside the wall; Harry hurried in.  And five minutes after Harry had gone inside a file of soldiers, coming around from another gate, surrounded the cab and arrested the driver.

Chapter V

On the Trail

Harry had reached Colonel Throckmorton without difficulty and before delivering Major French’s message, he explained his suspicions regarding the driver.

“What’s that?  ’Eh, what’s that?” asked the colonel.  “Spy?  This country’s suffering from an epidemic of spy fever —­ that’s what!  Still —­ a taxi cab driver, eh?  Perhaps he’s one of the many who’s tried to overcharge me.  I’ll put him in the guardhouse, anyway!  I’ll find out if you’re right later, young man!”

As a matter of fact, and as Harry surmised, Colonel Throckmorton felt that it was not a time to take chances.  He was almost sure that Harry was letting his imagination run away with him, but it would be safer to arrest a man by mistake than to let him go if there was a chance that he was guilty.  So he gave the order and then turned to question Harry.  The scout first gave Major French’s message, and Colonel Throckmorton immediately dispatched an orderly after giving him certain whispered instructions.