"Maybe this dum-dum will do some good," panted Nelson. "If it doesn't, nothing will stop it!" * * * * * Again he sighted until, finding those small, orange red eyes in line with his sight, he fired. This time the gray-brown monster uttered a titantic bellow of rage, halted, and began shaking its clumsy blunt head. "Hit it, by God!" exulted Nelson, and seized the momentary respite to slip two fresh cartridges into the Winchester's magazine. But, to his inexpressible dismay, the monster presently resumed its ponderous progress while the Jarmuthians in the howdah uttered taunting yells that reached him faintly, while the sun flares glinted on their brandished swords and lances. One of them plucked a fungus grenade from his belt and flung it with all his might in Nelson's direction. The missile fell to the earth far short of its destination and seemed to break rather than explode, at the same time expelling that deadly, greenish-yellow vapor which, blown away by a strong wind, fortunately came nowhere near the doomed aviator. "Oh! You will?" Nelson sighted swiftly at the grenade-thrower and fired, whereupon the Jarmuthian, some hundred and fifty yards distant, spun crazily about, flung both arms towards the amber-yellow sky and toppled from the howdah, for all the world like a diver in quest of pearls. From both breathless armies rose a terrific shout. Accustomed as they were to the visible destruction of the retortii, this noisy yet invisible death was appalling. But Nelson's agonized attention was not on the assembled armies, for nearer came the mountainous diplodocus, its lumbering strides making the howdah sway like a ship in a gale and preventing use of the portable retortii. * * * * * Nelson planted both feet, took fresh grip on his waning courage and shot again, this time aiming at a gigantic, black bearded warrior who seemed to be training one of those portable retortii upon him. Again the Winchester cracked and this time the black bearded man sank from sight back into the howdah, while his companions, uttering vengeful shouts, tossed more fungus bombs at the lone heroic figure barring their progress towards the six bound and shrieking maidens. Towering thrice as high as the largest African elephant, the diplodocus was now but seventy-five yards away. He had hit it, that Nelson could tell, for a large shower of blood sprayed from the monster's neck. Then, uttering a despairing curse, he sent a shot smacking squarely into the left shoulder, at the base of that mastlike neck with fervent hope of finding the heart. But the heavy bullet bothered the cyclopean reptile no more than a sting of a mosquito. On, on it came. In another minute it must stamp out Victor Nelson's life beneath feet as large as hogsheads. "Damn!" Nelson snapped the ejector lever, throwing out the spent cartridge.