CHAPTER

        I. A new venture in sandy beach
       II.  Mr. Harding declares himself
      III.  A naval visitor
       IV.  Aloft in A storm
        V. Peggy A heroine
       VI.  Farmer Galloway’s “Safe Deposit”
      VII.  A case for the authorities
     VIII.  Mr. Mortlake loses some drawings
       IX.  The flight of the “Silver cobweb”
        X. An aerial post office
       XI.  The marked bill
      XII.  What happened to Roy
     XIII.  Plot and counterplot
    XIV.  How they worked out
         XV.  What Mortlake did
        XVI.  The missing side-comb
       XVII.  Jimsy’s suspicions are roused
      XVIII.  A bolt from the blue
        XIX.  The gathering of the man-birds
         XX.  An unexpected meeting
        XXI.  The start of the sky cruise
       XXII.  The white peril
      XXIII.  Out of the clouds
     XXIV.  Friends and foes—­conclusion

CHAPTER I.

A new venture in sandy beach.

“It isn’t to be a barn; that’s one thing certain.  Who ever saw a barn with skylights on it?”

Peggy Prescott, in a pretty, fluffy morning dress of pale green, which set off her blonde beauty to perfection, laid down her racket, and, leaving the tennis-court, joined her brother Roy at the picket fence.  The lad, bronzed and toughened by his trip to the Nevada desert, was leaning upon the paling, gazing down the dusty road.

About a quarter of a mile away was the object of his contemplation—­a big, new structure, painted a staring red.  It had no windows, but in front were great sliding doors.  On its flat roof the forms of a dozen or more glazed skylights upreared themselves jauntily.

“No, it’s a work-shop of some sort.  But what?  Old man Harding is interested in it, that’s one thing sure.  I heard, too, that while we were away, cases of machinery had arrived and been delivered there, and that active work of some sort had been going forward ever since,” rejoined Roy, who was clad in white tennis flannels, with white shoes and an outing shirt, set off by a dark-red necktie.

“See Roy,” cried Peggy suddenly, “they’re putting up some sort of sign on it, or else I’m very much mistaken.”

“So they are.  I see men on some ladders, and now, look Peg, they are carrying up a big board with something painted on it.  Perhaps at last the mystery will be solved, as they say in the dime novels.”

“Can you read the printing on that sign?” inquired Peggy.

“Not a word.  I can see the letters to know that they are printed characters, but that’s all.  Tell you what, Peg, just run and get those glasses we used on the desert—­there’s a good fellow—­and we’ll soon find out.”

“Isn’t that just like a brother?  Always sending his long-suffering sister on his errands.”