"Yes, and Captain Fennelburt said he knew them."

"He did—but I deliberately gave him a totally wrong description of them. Smithers is fat, but he's short—about five six, I should think—and he certainly hasn't a mole under his eye. Tomlinson is fair, not dark, and I've never known him to touch a card either in the mess or out of it."

"There are some very queer cusses in the Service, I'll admit," remarked Major Sparrowhawk thoughtfully. "Getting a commission in war time isn't the same as in normal times. The chap may be pulling your leg, Cumberleigh. But why did you pal up to him and promise to take him to the theatre and all that?"

"Just to gain time, sir," answered Captain Cumberleigh. "I thought I'd ask your permission to telegraph to Sheerness Air Station. The inquiry could be worded discreetly, and if the reply's satisfactory there's no harm done. If it isn't, then we can take action."

"But what aroused your suspicions in the first instance?" asked the second-in-command.

Cumberleigh shrugged his shoulders.

"Just a little mannerism of his, sir," he replied. "I've never before tumbled across it on this side of the Rhine. Spent part of my far distant youth at Heidelburg, and one notices certain things. So I've practically put the fellow under arrest, only he doesn't know it. Young Jefferson'll take him fishing this afternoon, and in the meanwhile the wires can be getting busy."

"Bet you a double whisky you're wrong, Cumberleigh," offered Major Sparrowhawk.

"Done, sir," was the prompt reply.

Meanwhile Lieutenant Jefferson, assisted by a couple of air-mechanics, was getting his boat ready for the fishing expedition. One of the advantages of being in the Service in war time is that the uniformed owner of a private boat has a "pull" over his civilian confrère. The one can make use of his craft almost without restraint the other is hedged in by a formidable and galling array of restrictions that are none the less necessary for the well-being of the State.