His thoughts were interrupted by something dropping with a thud on the soft silver sward beside him. He groped for it and picked it up. It was a pair of binoculars, quite evidently lost overboard from one of the battling flyers. Now Cabot and his party would be able to observe the fight from closer quarters. Courteously he offered the glasses to the princess, and she in turn to the priest; but the latter declined them with a shrug, and again that quizzical smile, which a passing gleam of light revealed for a moment. So Lilla adjusted them and peered up into the velvet sky. Then she uttered a little exclamation of surprise. “Myles, Myles,” she cried, “our ships have at last lit their searchlights! Now, indeed, we shall win.” “We were winning already,” he replied, likewise peering into the black abyss above. “But why do you say that our ships are using their lights? It still seems to me as though they were not.” “Here, take the glasses and see for yourself,” said Lilla, and she handed them over, adding, as she looked into the sky with her naked eyes: “But now it seems as though the lights of our fliers have been extinguished. How strange!” Cabot adjusted the lenses to his own vision, and sure enough all the ships on both sides, were illumined. And still the young priest continued to smile. Cabot passed the binoculars back to Lilla, and again all the Cupian searchlights became dark to him. It was most mystifying. He glanced at his companions in perplexity and suddenly saw the teeth and eyeballs of Nan-nan glow phosphorescent. Then, and not until then, did the truth dawn on Cabot. “They are using the black light!” he gasped. “The black light?” Lilla inquired. “What is that? How can light be black?” “They are using the black light,” Myles continued, “just as my country, America, did to protect our convoys in the last great war on my own planet, Minos. Our warships swept the waters far and near with beams of the black light. These beams could not be seen by the German submarines, and thus did not reveal the position of our ships. When a beam played full upon a submarine, the luckless craft even then did not realize that it was observed; did not realize its fate until the high explosive projectile followed close in the wake of the light. Thus the scourge was driven from the seas, and the Germans never even suspected how it was done. I have discussed it with Toron, so this must be his idea. “Your glowing teeth and eyes revealed the secret to me, O Nan-nan. And that reminds me of a funny story. Major Rob Wood, of the American army, the inventor of the black light, was once demonstrating it in his laboratory to Sir Oliver Lodge shortly after the close of the war. The room appeared to be in darkness, and yet in fact a powerful searchlight was throwing a beam of black light straight across the middle of the room.