"These halls have a free communication by galleries, made in the same manner. If the materials of which the ant-hill is composed were only interlaced, they would fall into a confused heap every time the ants attempted to bring them into regular order. This, however, is obviated by their tempering the earth with rain-water, which, afterwards hardened in the sun, so completely and effectually binds together the several substances, as to permit the removal of certain fragments from the ant-hill without any injury to the rest; it, moreover, strongly opposes the introduction of the rain. I never found, even after long and violent rains, the interior of the nest wetted to more than a quarter of an inch from the surface, provided it had not been previously out of repair, or deserted by its inhabitants. "The ants are extremely well sheltered in their chambers, the largest of which is placed nearly in the centre of the building; it is much loftier than the rest, and traversed only by the beams that support the ceiling; it is in this spot that all the galleries terminate, and this forms, for the most part, their usual residence. "As to the underground portion, it can only be seen when the ant-hill is placed against a declivity; all the interior may be then readily brought in view, by simply raising up the straw roof. The subterranean residence consists of a range of apartments, excavated in the earth, taking an horizontal direction."[DB] [It seems rather surprising that the wood-ants should be able, with such materials as they employ, to make a dome-shaped structure, which shall be furnished with cells and galleries, and yet shall endure rain and wind, without being penetrated by the one or blown away by the other. If the hill be closely examined, the little sticks of which it is composed will be seen to have a definite, though not very regular arrangement; and it is a noteworthy circumstance that the longest are preserved for the galleries, being laid across each other in a very ingenious manner, so as to prevent the material from falling and filling up the galleries. This structure was shown very clearly in a huge ant-hill in Bagshot Park. We introduced a sheet of plate glass into the nest, so as to divide it perpendicularly into two halves, and having given the insects six weeks to repair damages, we removed one half of the hill, so that the whole interior of the other half could be seen through the glass. The whole economy of the nest was thus made clear, and the artificial arrangement of the materials showed itself very plainly on the roofs of the cells and galleries.] [Illustration] M. P. Huber, in order to observe the operations of the wood-ant with more attention, transferred colonies of them to his artificial formicaries, plunging the feet of the stand into water to prevent their escape till they were reconciled to their abode, and had made some progress in repairing it.