The woodland was deliciously green and cool and alive with the piping of robins.  Over the lake which glimmered faintly through the trees ahead came the whir and hum of a giant bird which skimmed the lake with snowy wing and came to rest like a truant gull.  Of the habits of this extraordinary bird Rex, barking, frankly disapproved, but finding his mistress’s attention held unduly by a chirping, bright-winged caucus of birds of inferior size and interest, he barked and galloped off ahead.

When presently Diane emerged from the lake path and halted on the shore, he was greatly excited.

There was an aeroplane upon the water and in the aeroplane a tall young man with considerable length of sinewy limb, lazily rolling a cigarette.  Diane unconsciously approved the clear bronze of his lean, burned face and his eyes, blue, steady, calm as the waters of the lake he rode.

The aviator met her astonished glance with one of laughing deference even as she marveled at his genial air of staunch philosophy.

“I beg your pardon,” stammered Diane, “but—­but are you by any chance waiting—­to be rescued?”

“Why—­I—­I believe I am!” exclaimed the young man readily, apparently greatly pleased at her common sense.  “At your convenience, of course!”

“Are you—­er—­sinking or merely there?”

“Merely here!” nodded the young man with a charming smile of reassurance.  “This contraption is a—­er—­I—­I think Dick calls it an hydro-aeroplane.  It has pontoons and things growing all over it for duck stunts and if the water wasn’t so infernally still, I’d be floating and smoking and likely in time I’d make shore.  That’s a delightful pastime for you now,” he added with a lazy smile of the utmost good humor, “to float and smoke on a summer day and grab at the shore.”

“I was under the impression,” commented Diane critically, “that in an hydro-aeroplane one could rise from the water like a bird.  I’ve read so recently.”

“One can,” smiled the shipwrecked philosopher readily, “provided his motor isn’t deaf and dumb and insanely indifferent to suggestion.  When it grows shy and silent, one swims eventually and drips home, unless a dog barks and a rescuer emerges from the trees equipped with sympathy and common sense.  I’ve a mechanician back there,” he added sociably.  “He—­he’s in a tree, I think.  I—­er—­mislaid him in a very dangerous air current.”

“Are you aware,” inquired the girl, biting her lip, “that you’re trespassing?”

“Lord, no!” exclaimed the aviator.  “You don’t mean it.  Have you by any chance a reputable rope anywhere about you?”

“No,” said Diane maliciously, “I haven’t.  As a rule, I do go about equipped with ropes and hooks and things to—­rescue trespassing hydroaviators, but—­” she regarded him thoughtfully.  “Do you like to float about and smoke?”

The sun-browned skin of the young aviator reddened a trifle, but his eyes laughed.