“I’d like to know what they’re doing there,” said Dick.

“So would I, but it’s open country, and they’re probably keeping a close lookout.  They’re really safer doing that in the open than on the roof of a house, out here in the country.”

“Because they can hide the heliograph?  It’s portable, isn’t it?”

“Yes.  They could stow it away in a minute, if they were alarmed.  I fancy we’ll find them using hilltops now as much as they can.”

“Harry, I’ve just thought of something.  If they’ve planned so carefully as this, wouldn’t they be likely to have country places, where they’d be less likely to be disturbed?”

“Yes, they would.  You’re right, Dick.  Especially as we get further and further away from London.  I suppose there must be plenty of places a German could buy or lease.”

“And perhaps people wouldn’t even know they were Germans, if they spoke good English, and didn’t have an accent.”

That suggestion of Dick’s bore fruit.  For the third station they found was evidently hidden away In a private park.  It was in the outskirts of a little village, and Harry and Dick had no trouble at all in finding out all the villagers knew of the place. “’Twas taken a year ago by a rich American gentleman, with a sight of motor cars and foreign-looking servants,” they were told.  “Very high and mighty he is, too —­ does all his buying at the stores in Lunnon, and don’t give local trade any of his patronage.”

The two scouts exchanged glances.  Their suspicions were confirmed in a way.  But it was necessary to be sure; to be suspicious was not enough for them.

“We’ll have to get inside,” he said under his breath to Dick.  But the villager heard, and laughed.

“Easy enough, if you’re friends of his,” he said.  “If not —­ look out, master!  He’s got signs up warning off trespassers, and traps and spring guns all over the place.  Wants to be very private, and that, he does.”

“Thanks,” said Harry.  “Perhaps we’d better not pay him a visit, after all.”

The village was a sleepy little place, one of the few spots Harry had seen to which the war fever had not penetrated.  It was not on the line of the railway, and there was not even a telegraph station.  By showing Colonel Throckmorton’s letter, Harry and Dick could have obtained the right to search the property that they suspected.  But that did not seem wise.

“I don’t think the village constables here could help us much, Dick,” said Harry.  “They’d give everything away, and we probably wouldn’t accomplish anything except to put them on their guard.  I vote we wait until dark and try to find out what we can by ourselves.  It’s risky but even if they catch us, I don’t think we need to be afraid of their doing anything.”

“I’m with you,” said Dick.  “We’ll do whatever you say.”

They spent the rest of the afternoon scouting around the neighboring country on their motorcycles, studying the estate from the roads that surrounded it.  Bray Park, it was called, and it had for centuries belonged to an old family, which, however, had been glad of the high rent it had been able to extract from the rich American who had taken the place.