before the boats disappeared, andy was hurrying up the hill.

“talk about your hidden treasure!” said the boy to himself. “lookin’ for concealed ideas beats it all hollow. now for the steel cylinders—whatever they are.”

passing the pump in the rear of the house, he realized that he was thirsty, and that reminded him that he was hungry. he thought first of the canned peaches and beans. then he recalled the ripe oranges and pineapples. ten minutes later, his face and fingers redolent of the combined juice of the two fruits, he was ready for his inviting investigation.

throwing off his hat and coat, he sought, first, the bench behind the shop. he secured wrenches and screw-drivers and loosened some of the parts of the six cylinder machine. but, after all, he had to shake his head.

“looks as if it is almost something,” he mused. “and it looks too as if it had nearly[66] worked. but i reckon it didn’t. and, if my uncle couldn’t make it go, what’s the use o’ my tryin’?”

plainly it was a gas accumulator or condenser of some kind. it even suggested an attempt to make a device for liquefying gases. the parts were so rusted that even after oiling them, andy could not operate them.

“i’ll pass that up for to-day,” thought the boy finally, his face wet with perspiration and his hands greasy with oil and brown from the rust. “now for the little model!”

he had a theory about the cylinders, but he had none about the model. in appearance, it resembled a wooden fan that the boy had once seen—a fan made by slitting half of a bit of straight-grained pine and then spreading the slit sections out like over-lapping feathers. in a way, too, it resembled a bird’s tail. the device to which the fan-like pieces were attached was so contrived as to open and close the tail-like extension.

andy carried the contrivance into the sunlight and carefully cleaned it. then, by grasping the central wooden shaft with a pair of pliers, he found he was able to turn it. a little brass cogwheel on the shaft operated in two[67] smaller wheels, one on each side. these, working on a beveled gear, moved levers simultaneously but in opposite directions. it required but a few minutes to discover that turning the shaft to the right drew down the fan-like blades on the right-hand side of the tail-like part and, at the same time, elevated those on the left-hand side.

“i guess it’s a toy,” argued the boy. “maybe the inside of an automatic bird. anyway, it works just as a bird spreads its tail when flying.”

further examining the miniature combination of wood and brass, andy made another discovery: the shaft not only turned both ways, but it, the beveled gears, and the connecting levers, worked forward and back. as the boy pushed the shaft backward, all the sheaves of the tail-like extension flew upward.

“it is a bird,” exclaimed andy. “it moves like a pigeon’s tail when the bird starts flying.”

pulling the shaft forward, reversed the operation, and the sheaves dropped downward.

“there she is comin’ down,” the boy cried aloud. “i’ve got it. it’s a new kind o’ boat rudder.”

what increased the resemblance to a bird’s[68] tail was another ingenious device—two rows of small cones just above and below the narrow ends of the sheaves. each blade, working upon a universal hinge, was free to move to the right and left. as they rose or fell under the pressure of the shaft, they pressed on the cones and spread out, fanwise.

then came the crowning discovery. the shaft could be moved forward or back and turned at the same time. as andy pushed it backward and gave it a twist to the right, the feather-like leaves depressed, assumed a diagonal line and spread out like a bird darting to the earth.

“old junk, is it?” muttered the boy, as he carried the model into the shop again. “maybe so. but, junk or not, i’ll bet there’s never been anything like that made before. and i’m goin’ to find out what it’s for.”

although andy had only partly investigated the fascinating mystery of the shop, he suddenly determined to have another look at the contents of the house. he was excited, hot, and dust-covered. passing through the dining room, an unopened bottle of lime juice in the cupboard caught his eye.

“might as well refresh myself,” chuckled[69] andy, with a boy’s hot-weather thirst. “a little florida ‘cup’ is just about my size on a day like this,” he went on; and rushing out to the grove, he secured three oranges and a small pineapple. a big glass pitcher was filled with fresh water. into this, using his pocketknife, andy sliced the fruit, and then on it poured a cup of lime juice, after which he took up the sugar box. it was alive with ants.

spreading a newspaper on the table, the boy poured out a quantity of sugar. the ants did not abandon their banquet. they rolled out with the sugar. the boy scratched his head. then he tried to chase the ants away. they were not easily chased. he got a little stick and began pushing them off the sugar. they went off one side and returned on the other. from scratching his head, andy fell to rubbing his chin. then he had a great thought.

“i’ll drown ’em,” he said to himself.

finding a shallow dish, the thirsty boy poured the sugar into it. the ants clung to their feast. he ran to the pump with the dish and filled it with water. the persistent ants were defeated. those that did not escape the deluge by hasty flight were drowned at once, victims of their appetites. in a few moments,[70] the top of the syrupy bath was thick with overcome ants. a few sweeps of the surface with his hand, and andy was free of his enemies.

“an’ i’ve got all the sugar without a speck o’ ants,” he chuckled again.

dumping the sweetening into the pitcher the boy stirred up the mess.

“it tastes awful good,” he said to himself, “but it’s kind o’ sweet.”

just then a big brown ant floated out from under a raft-like slice of pineapple.

“but i reckon plain water’s pretty good on a hot day,” he added less enthusiastically. dropping the pitcher of florida ‘cup,’ andy hastened to the pump and took a deep drink of pure water.

refreshed, he began systematically examining the living room. the bookshelves afforded a rich mine. from these, he advanced to the table where, manifestly, his uncle had done his reading and writing.

there was scarcely a thing here that did not give andy a new thrill of joy. everything seemed covered with writing or figures; sheets of paper, record books, piles of letters, engineering cross-ruled paper. one after another was put aside for later examination.

[71]

then andy came unexpectedly upon that which afterwards meant so much to him: the instant explanation of the puzzle of the little model. opening a pad of letter paper, he saw written in a careful hand, several pages addressed to mr. octave chanute, of chicago.

andy knew mr. chanute by reputation to be a skilled engineer and the father of airship experiments in america. he knew that it was mr. chanute’s experiments with kites and gliders on the sand dunes of indiana that had first interested the wright brothers, and the boy glowed with pride to know that his uncle had been in correspondence with such a man.

the letter that the boy found he read breathlessly—it was dated at least two weeks before his uncle’s death—and had not been mailed because it had not been finished. when the boy had read it twice and then stood, his eyes wide and his heart throbbing wildly, he made the resolution that he never wavered from, that turned the possibility of the making of an aeroplane into an insistent determination out of which came the pelican in which andy had his great adventure and in which he sought to solve, and did solve the mystery of the great pink pearl.

[72]

the momentous letter read:

“my dear mr. chanute:

“i am glad you received safely the report of my observations on bird flight in this region. as i told you, i spent three days in the vicinity of pelican island making notes on, and photographs of, the movements of these birds in the air. i hope the report will be of some assistance to you in your inquiry into the problem of ‘soaring birds.’ one thing we all know, and that is that birds do rise or soar at times without any apparent movement of wings, tail, or feathers. how this is done is, of course, a puzzle to us all. your theory that even in seemingly calm weather, when there is no noticeable agitation of the atmosphere, there may be a vertical column of rising air induced by imperceptible movements of the lower atmosphere, may be the explanation.

“i believe, as you do, that when we have found the explanation of how a bird ascends without the use of its wings, we will have made the longest step in conquering man-flight in the air.

“while it has no bearing on your present line of investigation, i cannot resist telling you[73] that the observations you asked me to make for you have greatly interested me in the subject of aviation in general. always a dabbler in physics and fond of experimenting, i have been led into working out an idea of my own. while watching the flight of birds, i could not but be astonished at the wide difference between their tail motions and the rear rudder or tail of the aeroplanes as i have observed them in magazine pictures.

“i was so much impressed by this lack of resemblance that i yielded to the temptation to try to adapt the natural apparatus of the bird to man’s artificial flyer. i have even made a small model of a guiding tail or rudder for aeroplanes, patterned as nearly as practicable after a bird’s tail. of course, i have no means of knowing how such an apparatus will work, but later i mean to send you some drawings, that you are at liberty to utilize as you see fit.

“these drawings will explain themselves. my object has been to secure a guiding contrivance that will not only alter the course of an aeroplane, but will at the same time equalize the darting tendency that i understand always follows a sudden turn to right or left. with it, i hope to lessen the need of flexing the[74] main planes of the machine when the rear rudder is used, a large part of the tendency to dart being absorbed, in theory at least, by the double action of my bird-tail rudder. the moving machine i hope may not only be steered up or down, or right and left, but one motion of the shaft will give the two movements which now must be made independently.”

here the letter came to an abrupt end.

“i knew it!” shouted andy. “i knew it was a rudder of some kind. it ain’t all clear to me yet. but one thing is clear enough. i can make a copy of that model. if it works, i’ll finish that letter. but, if it does, the plans of it aren’t goin’ to anyone ‘to do as he likes’ with ’em. i’ll have her patented.”

leaving the doors open, andy raced through the house, and in a moment or two had again disappeared within the shop in the grove.