[Illustration: "Come now, and fire the first shot in the warfare of the future." _See page 211._] "On the other side of those clouds. There, look down through that big rift, and you will see one of them." "Why, what a height we must be from the earth! The balloon looks like a little toy thing, but it must be a great clumsy contrivance for all that." "The barometer gives five thousand three hundred feet. You will soon see why I have come up so high. The balloons can rise to fifteen or twenty thousand feet, if they wish to, and in that way they could easily escape us; therefore, if one of them attempts to rise through those clouds, I shall send him back to earth in little bits." "And what are the other two air-ships doing?" "They are below the clouds, heading the balloons off from the Russian camp, which is about fifty miles to the north-westward. Ha! look, there go the searchlights!" As he spoke, two long converging beams of light darted across a broad space of sky that was free from cloud. They came from the _Ariel_ and the _Orion_, which thus suddenly revealed themselves to the astonished and disgusted Russians, one at each end of their long line, and only a little more than half a mile ahead of it. The searchlights flashed to and fro along the line, plainly showing the great masses of the aerostats' gas-holders, with their long slender cars beneath them. A blue light was burnt on the largest of the war-balloons, and at once the whole flotilla began to ascend towards the clouds, followed by the two air-ships. "Here they come!" said Arnold, as he saw them rising through a cloud-rift. "Come out and watch what happens to the first one that shows herself." He went out on deck, followed by Natasha, and took his place by one of the broadside guns. At the same time he gave the order for the _Ithuriel's_ searchlight to be turned on, and to sweep the cloud-field below her. Presently a black rounded object appeared rising through the clouds like a whale coming to the surface of the sea. He trained the gun on to it as it came distinctly into view, and said to Natasha-- "Come, now, and fire the first shot in the warfare of the future. Put your finger on the button, and press when I tell you." Natasha did as he told her, and at the word "Fire!" pressed the little ivory button down. The shell struck the upper envelope of the balloon, passed through, and exploded. A broad sheet of flame shot up, brilliantly illuminating the sea of cloud for an instant, and all was darkness again. A few seconds later there came another blaze, and the report of a much greater explosion from below the clouds. "What was that?" asked Natasha. "That was the car full of explosives striking the earth and going off promiscuously," replied Arnold. "There isn't as much of that aerostat left as would make a pocket-handkerchief or a walking-stick." "And the crew?"