But here we were doomed to defeat, at least temporarily; for no sooner had the first of our troops descended into the subterranean avenues than many of them came stumbling and fighting their way back to the surface, half-choked by the fumes of some deadly gas that the reptiles had liberated upon them. We lost a number of men here. Then I sent for Perry, who had remained discreetly in the rear, and had him construct a little affair that I had had in my mind against the possibility of our meeting with a check at the entrances to the underground city. Under my direction he stuffed one of his cannon full of powder, small bullets, and pieces of stone, almost to the muzzle. Then he plugged the muzzle tight with a cone-shaped block of wood, hammered and jammed in as tight as it could be. Next he inserted a long fuse. A dozen men rolled the cannon to the top of the stairs leading down into the city, first removing it from its carriage. One of them then lit the fuse and the whole thing was given a shove down the stairway, while the detachment turned and scampered to a safe distance. For what seemed a very long time nothing happened. We had commenced to think that the fuse had been put out while the piece was rolling down the stairway, or that the Mahars had guessed its purpose and extinguished it themselves, when the ground about the entrance rose suddenly into the air, to be followed by a terrific explosion and a burst of smoke and flame that shot high in company with dirt, stone, and fragments of cannon. Perry had been working on two more of these giant bombs as soon as the first was completed. Presently we launched these into two of the other entrances. They were all that were required, for almost immediately after the third explosion a stream of Mahars broke from the exits furthest from us, rose upon their wings, and soared northward. A hundred men on lidi were despatched in pursuit, each lidi carrying two riflemen in addition to its driver. Guessing that the inland sea, which lay not far north of Phutra, was their destination, I took a couple of regiments and followed. A low ridge intervenes between the Phutra plain where the city lies, and the inland sea where the Mahars were wont to disport themselves in the cool waters. Not until we had topped this ridge did we get a view of the sea. Then we beheld a scene that I shall never forget so long as I may live. Along the beach were lined up the troop of lidi, while a hundred yards from shore the surface of the water was black with the long snouts and cold, reptilian eyes of the Mahars. Our savage Mezop riflemen, and the shorter, squatter, white-skinned Thurian drivers, shading their eyes with their hands, were gazing seaward beyond the Mahars, whose eyes were fastened upon the same spot. My heart leaped when I discovered that which was chaining the attention of them all. Twenty graceful feluccas were moving smoothly across the waters of the sea toward the reptilian horde!