"If it's a call, it must be an important one, so far from civilization."

"Not necessarily. Don't you ever have calls that are not important?"

No answer came.

"Miss Brewster!" he called. "Oh, Voice! You haven't gone?"

Still no response.

"That isn't fair," he complained, making his way swiftly down, and satisfying himself by a peep about the angle commanding her point of the rock that she had, indeed, vanished. Sadly he descended to his own nook--and jumped back with a half-suppressed yell.

"You needn't jump out of your skin on my account," said Miss Polly Brewster, with a gracious smile. "I'm not a devilkin."

"You are! That is--I mean--I--I--beg your pardon. I--I--"

"The poor man's having another bashful fit," she observed, with malicious glee. "Did the bold, bad, forward American minx scare it almost out of its poor shy wits?"

"You--you startled me."

"No!" she exclaimed, in wide-eyed mock surprise. "Who would have supposed it? You didn't expect me down here, did you?"

Thereupon she got a return shock.

"Yes, I did," he said; "sooner or later."

"Don't fib. Don't pretend that you knew I was here."

"W-w-well, no. Not just now. B-b-but I knew you'd come if--if--if I pretended I didn't want you to long enough."

"Young and budding scientist," said she severely, "you're a gay deceiver. Is it because you have known me in some former existence that you are able thus accurately to read my character?"

"Well, I knew you wouldn't stay up there much longer."

"I'm angry at you; very angry at you. That is, I would be if it weren't that you really didn't mean it when you said that you really didn't want to see my face again."

"Did any one ever see your face once without wanting to see it again?"

"Ah, bravo!" She clapped her hands gayly. "Marvelous improvement under my tutelage! Where, oh, where is your timidity now?"

"I--I--I forgot," he stammered, "As long as I don't think, I'm all right. Now, you--you--you've gone and spoiled me."

"Oh, the pity of it! Let's find some mild, impersonal topic, then, that won't embarra.s.s you. What do you do under the shadow of this rock, in a parched land?"

"Work. Besides, it isn't a parched land. Look on this side."

Half a dozen steps brought her around the farther angle, where, hidden in a growth of shrubbery, lay a little pool of fairy loveliness,

"That's my outdoor laboratory."

"A dreamery, I'd call it. May I sit down? Are there devilkins here?

There's an elfkin, anyway," she added, as a silvered dragon-fly hovered above her head inquisitively before darting away on his own concerns.

"One of my friends and specimens. I'm studying his methods of aviation with a view to making some practical use of what I learn, eventually."

"Really? Are you an inventor, too? I'm crazy about aviation."

"Ah, then you'll be interested in this," he said, now quite at his ease.

"You know that the mosquito is the curse of the tropics."

"Of other places, as well."

"But in the tropics it means yellow fever, Chagres fever, and other epidemic illness. Now, the mosquito, as you doubtless realize, is a monoplane."

"A monoplane?" repeated the girl, in some puzzlement. "How a monoplane?"

"I thought you claimed some knowledge of aviation. Its wings are all on one plane. The great natural enemy of the mosquito is the dragon-fly, one of which just paid you a visit. Now, modern warfare has taught us that the most effective a.s.sailant of the monoplane is a biplane. You know that."

"Y-y-yes," said the girl doubtfully.

"Therefore, if we can breed a biplane dragonfly in sufficient numbers, we might solve the mosquito problem at small expense."

"I don't know much about science," she began, "but I should hardly have supposed--"

"It's curious how nature varies the type of aviation," he continued dreamily. "Now, the pigeon is, of course, a Zeppelin; whereas the sea urchin is obviously a balloon; and the thistledown an undirigible--"

"You're making fun of me!" she accused, with sharp enlightenment.

"What else have you done to me ever since we met?" he inquired mildly.

"Now I AM angry! I shall go home at once."

A second far-away PLOP! set a period to her decision.

"So shall I," said he briskly.

"Does that signal mean hurry up?" she asked curiously.

"Well, it means that I'm wanted. You go first. When will you come again?"

"Not at all."

"Do you mean that?"

"Of course. I'm angry. Didn't I tell you that? I don't permit people to make fun of me. Besides, you must come and see me next. You owe me two calls. Will you?"

"I--I--don't know."

"Afraid?"