This is an adventure book. Hurray, Jack, sure we can hear you, cried Frank, bending forward to speak into the transmitter on the stand before him. Then as Jack's voice continued calling without paying him any attention, he straightened up and laughed'. Gee. I forgot', he laughed. Laying down his headpiece, he ran across the room; opened a door into the power house adjoining where the mechanic was dozing over his pipe and called to him to throw on the generator. Galloping back, as the man obeyed, Frank again snatched up his headpiece. Bob already was bending over a transmitter, calling to Jack in faraway New Mexico. Both boys listened with straining ears for the response. Presently Jack answered: 'I can hear you, but only very faintly. Put that band piece on the talking machine'.