Cyrus Harding, wishing to complete his performance, established a pigeon-house in a corner of the poultry-yard. There he lodged a dozen of those pigeons which frequented the rocks of the plateau. These birds soon became accustomed to returning every evening to their new dwelling, and showed more disposition to domesticate themselves than their congeners, the wood-pigeons. Lastly, the time had come for turning the balloon-case to use, by cutting it up to make shirts and other articles; for as to keeping it in its present form, and risking themselves in a balloon filled with gas, above a sea of the limits of which they had no idea, it was not to be thought of. It was necessary to bring the case to Granite House, and the colonists employed themselves in rendering their heavy cart lighter and more manageable. But though they had a vehicle, the moving power was yet to be found. But did there not exist in the island some animal which might supply the place of the horse, ass, or ox? That was the question. "Certainly," said Pencroft, "a beast of burden would be very useful to us until the captain has made a steam cart, or even an engine, for some day we shall have a railroad from Granite House to Port Balloon, with a branch line to Mount Franklin!" One day, the 23rd of December, Neb and Top were heard shouting and barking, each apparently trying who could make the most noise. The settlers, who were busy at the Chimneys, ran, fearing some vexatious incident. What did they see? Two fine animals of a large size, who had imprudently ventured on the plateau, when the bridges were open. One would have said they were horses, or at least donkeys, male and female, of a fine shape, dove-coloured, the legs and tail white, striped with black on the head and neck. They advanced quietly without showing any uneasiness, and gazed at the men, in whom they could not as yet recognise their future masters. "These are onagas!" cried Herbert, "animals something between the zebra and the conaga!" "Why not donkeys?" asked Neb. "Because they have not long ears, and their shape is more graceful!" "Donkeys or horses," interrupted Pencroft, "they are 'moving powers,' as the captain would say, and as such must be captured!" The sailor, without frightening the animals, crept through the grass to the bridge over Creek Glycerine, lowered it, and the onagas were prisoners. Now, should they seize them with violence and master them by force? No. It was decided that for a few days they should be allowed to roam freely about the plateau, where there was an abundance of grass, and the engineer immediately began to prepare a stable near the poultry-yard, in which the onagas might find food, with a good litter, and shelter during the night.