to bid farewell to the soldiers who were going - where? No one
knew. That was the mystery of the morning. Everyone understood
that the troops were off; that they had their orders. But not
even the officers themselves knew where, it seemed.

"Here we are - here's a car!" said the officer called Cecil.
"Jump aboard, young 'uns! We know where you're going, right
enough. Might as well save some time."

And so in a few minutes they reached the great barracks. Here the
bustle that had been so marked about the station was absent. All
was quiet. They were challenged by a sentry and Harry asked for
the officer of the guard. When he came he handed him Wharton's
letter. They were told to wait - outside. And then, in a few
minutes, the officer returned, passed them through, and turned
them over to an orderly, who took them to the room where Colonel
Throckmorton, who was seemingly in charge of important affairs,
received them. He returned their salute, then bent a rather
stern gaze upon them before he spoke.




Chapter IV


The House of the Heliograph


"You know your way about London?" he asked.