It was with one of these that Gerald met with an unpleasant adventure one day when they had been but a short time ’out.’ He had strolled in alone, in the early morning, as was now his almost constant habit, and went towards the cage of a creature called by the Martians an _amalpi_. Gerald was especially interested in it on account of its resemblance to an immense unicorn. It was, indeed, something between that fabled creature and a rhinoceros. It had a very long, straight, sharp horn upon the frontal bone, and a body very much like a heavily-built cart-horse, covered with skin almost as thick as that of an elephant. It was a most savage, dangerous creature, and all attempts to tame it, even in the smallest degree, had failed. When Gerald walked up to its cage on this particular occasion he met with a surprise, for the cage was empty and the barred gate was standing ajar. Ere he had time to consider what this might mean he received a second surprise. There was a loud, bellowing roar, and the next he knew was that the creature itself was charging down upon him with lowered head like a bull, the terrible, long, sharp horn pointed straight at him. For an instant the young fellow stood as if spell-bound; then, by a happy flash of thought, he dashed into the empty cage and pulled the gate to after him. It fastened, as he knew, automatically, with a huge spring-catch. A moment later there was a frightful crash as the ferocious animal ran full tilt at the bars, its long horn pushing between them, and just failing to reach Gerald by some few inches. For some time he had the novel experience of being a prisoner in the great cage, while his enemy, furious with disappointment, charged again and again at the bars. Such was the strength and determination of its rushes that it seemed almost as if the bars must give way. At last the noise of its bellowing brought some of the keepers upon the scene. Then Gerald had an opportunity of learning more of the weapons the Martians were armed with, and how they used them. Each keeper carried in his hand one of the large wands or staves, with triple points at the top, similar to those the soldiers had carried who had marched Gerald as a prisoner before the ’Ogre’ and his chief. Gerald had seen similar wands many times since, but had never seen how they were used. Nor was he, indeed, much the wiser now. All he saw was a slight flash of very brilliant light which seemed to leap from the tridents towards the great roaring animal, as it stood for a moment tossing its head and stamping its feet ere charging down upon the rescue-party. But it never started upon its rush, for, lo! it suddenly sank upon its knees and rolled helplessly over upon the ground, where it lay quiet and still—a big, inert mass. The keepers opened the gate, and Gerald walked out, wondering greatly at what he had seen, but unable to ask any questions, because he could not speak their language.