"That effect is exactly what Teddy and I have for so long laboured to produce," was my answer, as I stood there fascinated by the sparks and the slight crackling which reached our ears where we stood. The fact was that though our apparatus was half a mile away, yet upon those steel strands, as well as upon the copper lightning-conductor, the electric waves which we were discharging--a new development of the discovery of Heinrich Hertz--was such as to spark over all the intervening gaps, even though the space where the insulators were inserted was quite three inches. It was a phenomenon such as had never before been witnessed by any experimenter in electricity. The theories I had formed and so often discussed with Teddy were now proved to be quite sound, for they had resulted in the construction of that apparatus which must, I knew, be most deadly to any Zeppelin. The sparks, as we watched them, suddenly ceased. For a moment I stood surprised, yet next instant realised that Teddy had, no doubt, some very good reason for stopping the engine. Somebody might have come upon the scene, and we were always extremely cautious that nobody should know in what we were engaged. The neighbours knew us as airmen, and believed we were engaged in making some kind of new propellers. What I had seen in those few minutes, the flashing crackling sparks running over the surface of those porcelain insulators and, indeed, over part of the wooden pole--for it happened to have been raining until an hour before, and all the surfaces were damp--was, to me, sufficient to cause me to hold my breath in excitement. "We have made a great and most important discovery to-day, Roseye," I said as calmly as I could, as together we walked back to the shed. "This discovery is undreamed of by Germany. It will give us power over any Zeppelin which dares to come to our shores, providing that we can approach sufficiently near." "Ah! if you can," replied the girl at my side. "No doubt we shall increase the range," I replied. "We have, this evening, established the one most important fact that our apparatus is really capable of directing the rays, and that between metal and metal we can now, as Hertz endeavoured to, set up an electric spark from a distance." "You certainly have done that--but I don't yet see the trend of your argument, Claude. I know I'm only a woman and unversed in technicalities, so please forgive me, won't you?"