Andy gasped, and then exclaimed.

“Once more you’ve gone and seen through the riddle that knocked me silly, Frank.  That’s just what it must mean—­the pay-car would offer fat pickings, all in cash; and they’ve held up their flight to Canada just to try and gobble it.  Oh! what a slick game, with Todd giving false information, and perhaps just leading the police further and further away from Bloomsbury tonight, so as to leave the pay-car next to unprotected.  Yes, and doesn’t he go on like this, ’he says keep low, and trust to him’?  That must mean Todd, don’t you think?”

“I read it that way,” replied his cousin tersely, as he rubbed his chin in a reflective fashion; for they were now grappling with a dangerous problem, and Frank was only too well aware of the fact that a slip might upset all calculations, as well as possibly endanger their lives; since they were dealing with reckless men, and no boyish rivals like Percy Carberry and Sandy Hollingshead.

“Do you think this was meant for the other one of the bank thieves?” Andy went on to ask.

“It could hardly have been for any one else, Andy.  There must have been more to the letter, but the rest dried before he blotted it.”

“And that fellow is in hiding somewhere, perhaps watching the biplane, and ready to fight before letting it be retaken, because they depend on it for their get-away to the great lakes and Canada;” Andy further observed.

“Yes, just as you say,” the other remarked.

“And now since we’ve learned this much, Frank, what are we going to do about it—­try and find where the stolen biplane is, and do something so as to make it no good for their purpose; or just slip away, go round a little like we were just out for a spin, and getting back to Bloomsbury, put them wise?”

“Neither, just yet anyhow,” the older Bird boy remarked.  “Not the first, because it would be taking big chances, if, as we believe, one of the robbers is concealed near where the stolen biplane may happen to be lying, partly hidden with dead leaves, so it couldn’t be noticed from above; and he would be apt to do something we’d find unpleasant.  And as for going back and telling, we’ll have to be mighty careful there.”

“And why, Frank?”

“Well, to begin with, even the walls have ears, they say; and if the police were suddenly called back from their hunt to the southwest, the fact might get to the robbers; and you know what would happen then.”

“Oh!” said Andy, shrugging his shoulders, “I suppose they’d just throw this second job up, and cut stick for Canada, as fast as they could make the aeroplane spin, which would be too bad for Chief Waller, and Joe Green, and the rest of that bunch at Headquarters, who are already figuring on how they’ll spend their reward money they hope to get when the bank pays for rounding-up the two thieves.”

“But, perhaps, if we just told our fathers, Andy, they might get a few bold men together and lay a beautiful trap for the fellows so that when they broke into the pay-car, they would be made prisoners.”