“We say nothing,” replied the disputatious Overtop.  “We only wait for proof.  It is easy to find out whether a signal is meant or not.  Rub the window now.”

Maltboy did so, concluding the act with an unmistakable flourish of the handkerchief.  Whereupon the tall girl averted her face, pulled down the curtain, and eclipsed herself.

Wilkeson and Overtop laughed, and, with a common impulse, punched Maltboy triumphantly in the ribs—­a friendly salute that was always vastly amusing to that gentleman.

“Be it understood, at this stage of affairs,” said Marcus, solemnly, “that I reject the Overtop theory, and wash my hands of all responsibility for Maltboy’s misdeeds.—­Hallo!  There he is again.”

“Who?  Where?” exclaimed his two friends.

“In the house nearly opposite—­the one with the grape arbor.  Isn’t he a fine old fellow?”

Overtop and Maltboy looked, and there saw, sitting at a window, and placidly gazing out of it, an old gentleman with long and thick white hair, a ruddy face, a white neckcloth, and a large projecting shirt frill—­which were all the peculiarities of person and dress that could be distinctly made out.  He was smoking a long pipe, and placidly rocking himself to and fro.  His appearance, through the two windows, was that of a finely preserved relic of a past generation,

“He always has a long pipe in his mouth, and looks benignantly into the open air,” said Wilkeson,

“So even you are not wholly devoid of curiosity, and do take some interest in the people on our block,” remarked Matthew Maltboy,

“I have noticed the old gentleman often, when I have been reading near the window; and own that I should like to know him.  I think, too, from certain signs, that he would not object to knowing me.  Unless I am much mistaken, he has bowed to me several times.  But fearing that the supposed bow might have been nothing more than a sleepy nod, I have never ventured to answer it.  Step back a moment, and see if he observes me.”

Maltboy and Overtop retired a few paces.  A moment afterward, the old gentleman looked over to Wilkeson, and made a bow at him about which there could be no mistake.

“Answer him.”  “Answer him,” said his two friends.  Acting upon this advice, Marcus Wilkeson, blushing, returned a courtly salute, which was immediately reciprocated by a still lower bow, and a pleasant smile from the old gentleman.  Wilkeson bowed again, and added a smile.  The old gentleman did the same; and this odd exchange of civilities was beginning to get awkward for Wilkeson, when the old gentleman’s attention was suddenly called off.