top they began to put in pieces of wet dirt almost level, and in such a way as to make a ledge; and by joining on more dirt to it, it would meet the ledge made from the opposite wall so as to make a roof: these roofs over the galleries were about a quarter of an inch across. The ceilings over the large halls were sometimes as much as two inches in breadth, and to support these they raised pillars; and beginning in the corner where two walls joined, they would commence the ceiling with a ledge, while from the top of each pillar they would also build out a layer of earth a little rounded on the top; these they continued to add to until all met and made a complete cover for the hall." "I wonder it did not fall, Uncle Philip, before they could join it together." "Mr. Huber says that he thought several times it would fall, from the rain which was dropping upon it all the time; but he found that the pieces held together, and that the rain, instead of hurting it, only made it more solid. All that it wants, when the ants have done, is a little heat from the sun to bake it hard, and then it appears like a piece of solid dirt. Sometimes, if the rain be violent, the apartments will be destroyed, especially if the arches are not built strongly; and when this happens, the little creatures go to work very patiently and rebuild them." "And how long, Uncle Philip, did it take the ants to put another story on their house?" "Between seven and eight hours; and they had hardly finished one before they began another, but they had not time to finish it, for the rain stopped before they had built much: however, they kept on, taking advantage of the wet earth; but a cold drying wind soon sprang up, and the earth would not stick; so they stopped: but what do you think they did with the new story which they had not time to finish?" "What _did_ they do, Uncle Philip?" "Pulled every part of it to pieces, and scattered the dirt here and there over the roof of the story which they had finished. "I will tell you another story about these ants, boys, which I think is most wonderful, because it appears so much like reason. These insects all seem to work separately,--I mean without attending to the work of others: of course sometimes the work done by different ants on opposite sides of the same gallery or hall will not suit: one wall will be higher than the other, so that the ceilings will not meet. Mr. Huber saw just such a case; the ceiling which was begun from one wall would just have reached the other wall about half-way up; and while he was wondering how the ants would cure the fault, one of them came, and looking at the work, seemed to know that it was wrong, and immediately began by taking down the ceiling from the lower wall; he then raised it to the same height with the opposite wall, and made a new ceiling in Mr. Huber's presence with the pieces of the old one." "Uncle Philip, if that ant did not know how to think, I am mistaken."