"That's what I wanted to know," continued his uncle. "You see, I gave a full minute's liberation. You say your magnetos were cut out for three-quarters of a minute only. That was because I couldn't see you during the last fifteen seconds. You were hidden from direct observation by an intervening ridge." "I see," observed Peter, nodding his head. "So do I now," added Strong. "I had hoped that the rays would be active beyond an obstruction of that sort. Had they been so, it would be possible to keep a whole fleet of aeroplanes pinned to the ground, unable to rise. It is a curious point as to what does happen: whether the electric fluid is deflected by intervening ground or whether it stands dead up against it--like a beam of light, for instance, playing upon a dead black substance. Then, again, we've proved that the metal fuselage affords no insulation to protect the magnetos from the rays." "Nor does a sheet of rubber," announced Peter. "I tried that little stunt on my own." "Did you?" remarked his uncle. "Evidently you hadn't much faith in my invention." "Not that," Peter hastened to assure him. "It was simply to see if there were an easy means to render the ignition system immune from the rays. I was jolly glad I wasn't able to baulk you, Uncle." "Well, that's a good thing," said Brian Strong. "The next step is to dismantle the projector, pack up the vital portions of the apparatus, and make a hurried exodus from Rioguay. It's easier said than done, Peter, and unless I'm very much out in my calculations, we'll have our hands full when we do come to tackle the problem." "What's to prevent our going down to Tepecicoa and taking passage to Bahia? There's a steamer running once a week." "Nothing to prevent us making a start," replied his uncle, "but the chances of our getting clear of Rioguay by that means are very remote. There would be a regrettable accident--according to the Rioguayan official version for foreign consumption--and there you are, or, rather, are not." "But isn't there a British consul in Tepecicoa?" persisted Peter, who found it hard to believe that a British subject is not always, and in all circumstances, free to indulge his propensity for foreign travel.