The tents of the Monguls thus made were, of course, very comfortless homes. They could not be kept warm, there was so much cold air coming continually in through the crevices, notwithstanding all the people's contrivances to make them tight. The smoke, too, did not all escape through the hoop-hole above. Much of it remained in the tent and mingled with the atmosphere. This evil was aggravated by the kind of fuel which they used, which was of such a nature that it made only a sort of smouldering fire instead of burning, like good dry wood, with a bright and clear flame. The discomforts of these huts and tents were increased by the custom which prevailed among the people of allowing the animals to come into them, especially those that were young and feeble, and to live there with the family. In process of time, as the people increased in riches and in mechanical skill, some of the more wealthy chieftains began to build houses so large and so handsome that they could not be conveniently taken down to be removed, and then they contrived a way of mounting them upon trucks placed at the four corners, and moving them bodily in this way across the plains, as a table is moved across a floor upon its castors. It was necessary, of course, that the houses should be made very light in order to be managed in this way. They were, in fact, still tents rather than houses, being made of the same materials, only they were put together in a more substantial and ornamental manner. The frame was made of very light poles, though these poles were fitted together in permanent joinings. The covering was, like that of the tents, made of felt, but the sheets were joined together by close and strong seams, and the whole was coated with a species of paint, which not only closed all the pores and interstices and made the structure very tight, but also served to ornament it; for they were accustomed, in painting these houses, to adorn the covering with pictures of birds, beasts, and trees, represented in such a manner as doubtless, in their eyes, produced a very beautiful effect. These movable houses were sometimes very large. A certain traveler who visited the country not far from the time of Genghis Khan says that he saw one of these structures in motion which was thirty feet in diameter. It was drawn by twenty-two oxen. It was so large that it extended five feet on each side beyond the wheels. The oxen, in drawing it, were not attached, as with us, to the centre of the forward axle-tree, but to the ends of the axle-trees, which projected beyond the wheels on each side. There were eleven oxen on each side drawing upon the axle-trees. There were, of course, many drivers. The one who was chief in command stood in the door of the tent or house which looked forward, and there, with many loud shouts and flourishing gesticulations, issued his orders to the oxen and to the other men.