Kenneth wrote down the letters as he read them. "By George!" he cried. "In English it reads: ’Tell our friend it is now due east.’" "What’s due east?" Captain Adams exclaimed. "Try the other paper." "The first word is _bedeutend_, ’considerable,’" said Kenneth, writing. "The English of it all is, ’Considerable movement in the rear.’" The officers glanced at one another. "We’ve had a spy among us, then," said the captain quietly. "Where did you get this, Randall?" Harry explained, without however naming the man whom, in common with Kenneth, he now suspected. But his reticence was unnecessary. "It’s that fellow Stoneway, without a doubt," said one of the lieutenants. "He makes the most weird sounds on his flute. You’ll arrest him, Adams?" "Wait a little. There’s a deep-laid scheme here. There’s more than one man involved. Who is ’our friend’?" "I must tell you what I saw last night, sir," said Kenneth. He described the stealthy exit from the gate in the lane, and the discovery that it led from Monsieur Obernai’s garden--behind the house in which they were then assembled. Captain Adams whistled under his breath. "Rather serious for our polite Alsatian host," he said. "We must get to the bottom of this. It won’t do to act too hastily. We must catch the fellow at it." "But hang it all, we can’t stop here under the roof of a spy," said a lieutenant. "If I may suggest, sir," said Kenneth, "do nothing yet. Nobody knows about this except ourselves. If you leave the house or show any sign of suspicion, those who are involved will smell a rat, and we shall perhaps fail to learn all there is to be learnt. Wouldn’t it be better if you go on as usual, and let Randall and me, and perhaps Murgatroyd, keep a watch on the lane?" "But Obernai won’t appear in the lane," said the captain. "Very likely not, sir. I believe his work is done in the house. You remember the lamp signalling we saw in the church tower." "That’s in our hands now." "Yes, and the light now comes from due east." "You think that’s it? Have you seen a light?" "No, sir; but last night I caught a sudden glimpse of a bat flying above my head in the lane; it was for only the tenth of a second, just as if the bat had crossed a pencil of light. But I was puzzled, because there was no light visible. I can’t help thinking that it has some connection with this discovery, and if you’ll give us leave to keep a look-out at night, we may make sure of it and give you positive grounds for taking action." "What about Stoneway? Hadn’t we better keep him under observation?" "Leave him to us, sir. I’d give him plenty of rope." "And keep enough to hang him afterwards," said the lieutenant of his platoon.