“‘The air is the swallow’s appropriate element, and it is the nature of the bird to be ever on the wing. It eats flying, bathes flying, and sometimes even feeds its young when flying. It glides through the air with no effort, with perfect ease, conscious of being in its own domain. It explores aërial space in all its dimensions, as if to enjoy it to the utmost, and its delight in the act is expressed by little cries of rapture. It may be seen giving chase to flying insects and following with supple agility their evasive and tortuous course; or it may leave one to pursue another and snap up a third in passing; or, again, it lightly skims the surface of land and water to catch any that may be gathered there for the sake of coolness and moisture; or, finally, it may in its turn be driven to flee with all speed before the lightning-like onset of some bird of prey. Always in full control of its movements even when flying at topmost speed, it is continually changing its course, describing in the air a bewildering maze whose paths cross, interlace, recede from and approach one another, meet, wind, ascend, descend, interweave, and mingle in a thousand different ways and after a plan so complicated as to defy representation to the eye by the art of drawing and scarcely to lend itself to description for the imagination through the medium of speech.’ “We have three kinds of swallows in France, of which the best known is the martin, black above with glints of blue, and white beneath and on the rump. It builds its nest in window-corners, under the eaves of roofs, and on the cornices of buildings. The materials it uses are fine soil, chiefly that which is deposited by earthworms, after digestion, in little mounds over our fields and gardens. The swallow carries it, a beakful at a time, mixes it with a little viscous saliva to make it stick together, and lays it by courses until it takes the shape of a hemisphere attached to the wall and provided with a small opening at the top. Bits of straw give additional firmness to the masonry; and, finally, the interior is lined with an abundance of little feathers. The laying consists of four or five pure white eggs without any spots. “The nests are used year after year by the same pairs of birds, being recognized by them on their annual return in the spring and made as good as new with a few repairs. If some are left vacant by reason of the owners’ death in distant lands, new couples profit by the fact.” “Don’t they ever quarrel over the old nests?” asked Jules.