“Yes, sir.”

“You might as well understand what it’s all about,” said the major.  “You see, we’re moving a lot of troops.  And it is of the utmost importance for the enemy to know all about the movement and, of course, just as important for us to keep them from learning what they want to know.  So we are covering the movement as well as we can.  Even if they learn some of the troops that are going, we want to keep them from finding out everything.  Their spy system is wonderfully complete and we have to take every precaution that is possible.  It is most important that you deliver this message to Colonel Throckmorton.  Repeat it to me exactly,” he commanded.

They did so, and, seemingly satisfied, he let them go.  But just as they were leaving, he called them back.

“You’d go back by the underground, I suppose,” he said.  “I’m not sure that you can get through for the line is likely to be taken over, temporarily, at any moment.  Take a taxicab —­ I’ll send an orderly with you to put you aboard.  Don’t pay the man anything; we are keeping a lot of them outside on government service, and they get their pay from the authorities.”

The orderly led them to the stand, some distance from the station, where the cabs stood in a long row, and spoke to the driver of the one at the head of the rank.  In a moment the motor was started, and they were off.

The cab had a good engine, and it made good time.  But after a little while Harry noticed with some curiosity that the route they were taking was not the most direct one.  He rapped on the window glass and spoke to the driver about it.

“Got to go round, sir,” the man explained.  “Roads are all torn up the straight way, sir.  Won’t take much longer, sir.”

Harry accepted the explanation.  Indeed, it seemed reasonable enough.  But some sixth sense warned him to keep his eyes open.  And at last he decided that there could be no excuse for the way the cab was proceeding.  It seemed to him that they were going miles out of the way, and decidedly in the wrong direction.  He did not know London as well as a boy who had lived there all his life would have done.  But his scout training had given him a remarkable ability to keep his bearings.  And it needed no special knowledge to realize that the sun was on the wrong side of the cab for a course that was even moderately straight for Ealing.

They had swung well around, as a matter of fact, into a northwestern suburban section, and once he had seen a maze of railway tracks that meant, he was almost sure that they were passing near Willisden Junction.  Only a few houses appeared in the section through which the cab was now racing and pavements were not frequent.  He spoke to Dick:  in a whisper.

“There’s something funny here,” he said.  “But, no matter what happens pretend you think it’s all right.  Let anyone who speaks to us think we’re foolish.  It will be easier for us to get away then.  And keep your eyes wide open, if we stop anywhere, so that you will be sure to know the place again!”