But among all the wind instruments of the Middle Ages, the organ was the one most imposing in its nature, and destined to the most glorious career. The only instrument of this kind known by the ancients was the water-organ, in which a key-board of twenty-six keys corresponded to the same number of pipes; and the air, acted upon by the pressure of water, produced most varied sounds. Nero, it is said, spent a whole day examining and admiring the mechanism of an instrument of this kind. The water-organ, although described and commended by Vitruvius, was not much in use in the Middle Ages. Eginhard speaks of one constructed, in 826, by a Venetian priest; and the last of which mention is made existed at Malmesbury in the twelfth century. But this latter might be regarded more in the light of a steam-organ; for, like the warning whistles of our locomotives, it was worked by the effects of the steam of boiling water rushing into brass pipes. [Illustration: Fig. 169.--Pneumatic Organ of the Fourth Century. (Sculpture of that date at Constantinople.)] The water-organ was, in very early times, superseded by the pneumatic or wind-organ (Fig. 169), the description of which given by St. Jerome agrees with the representations on the obelisk erected at Constantinople in the time of Theodosius the Great. We must, however, fix a date as late as the eighth century for the introduction of this instrument into the West, or at least into France. In 757, Constantine Copronymus, Emperor of the East, sent to King Pépin a number of presents, among which was an organ that excited the admiration of the court. Charlemagne, who received a similar present from the same monarch, had several organs made from this model. These were provided, according to the statement of the monk of Saint-Gall, with “brazen pipes which were acted on by bellows made of bull’s hide, and imitated the roaring of thunder, the accents of the lyre, and the clang of cymbals.” These primitive organs, notwithstanding the power and richness of their musical resources, were of dimensions which rendered them quite portable. It was, in fact, only in consequence of its almost exclusive application to the solemnities of Catholic worship that the organ became developed on an almost gigantic scale. In 951, there existed in Winchester Cathedral an organ which was divided into two parts, each provided with its apparatus of bellows, its key-board, and its organist. Twelve bellows above, and fourteen below, were worked by seventy strong men, and the air was distributed by means of forty valves into four hundred pipes, arranged in groups or choirs of ten, each group corresponding with one of the twenty-four keys of each key-board (Fig. 170). [Illustration: Fig. 170.--Great Organ, with Bellows and double Key-board, of the Twelfth Century. (MS. at Cambridge.)]