Transcriber's Notes:
Reading edition
Retained inconsistent hyphenation ("reentered" vs. "re-entered").
Page 12, changed "anyhere" to "anywhere" ("we can go anywhere").
Page 13, removed unnecessary quote before "In the letter, over his own signature." Changed "propellor" to "propeller" ("propeller forces the air-ship").
Page 16, changed "Yon" to "You" ("You can handle the machine").
Page 18, changed "times" to "time" ("right time arrives").
Page 19, changed "geen" to "been" ("chum has been getting").
Page 26, changed "Mat" to "Matt" ("get a look at Matt").
Page 27, changed "nearer" to "neared" ("As they neared").
Page 28, changed "bulding" to "building" ("big building were closed").
Page 29, changed "crossel" to "crossed" ("curious expression crossed"). Changed "outwarlly" to "outwardly" ("outwardly looked precisely"). Changed "varandaed" to "verandaed."
Page 30, changed "thicked" to "thicker" ("thicker grew the").
Page 31, changed "clutchel" to "clutched" ("clutched Pete's arm").