pinging against e, imparts a vibratory motion to the column of air in the pipe, the result of which is a mu- sical note, dependent fur its pitch on the length of that column of air, and consequently on the length of the body of the pipe : by doubling the length of the pipe we obtain a note of half the pitch, or lower by an octave. Such is the geneial princii)le of all mouth-pipes, wheth- er of wood or of metal, subject to considerable diver- sities of detail. Metal pipes have generally a cylin- drical section ; wooden pipes a square or oblong sec- tion. A mouth-pipe may be stopped at the upper end by a plug called a tompion, the effect of which is to lower the pitch an octave, the vil)rating column of air being d(mbled in length, as it has to traverse the pipe twice before makini;; its exit. Pipes are sometimes half- stopped, having a kind of chimney at the top. The reed- pipe cousists of a reed placed inside a metallic or occa- si(nially a wooden pipe. This reed is a tube of metal, with the front part cut away, and a tongue or spring put in its place. The lower end of the spring is free, the upper end attached to the top of the reed ; hy the admis- sion of air iuto the pipe the spring is made to vibrate, and, in striking either the edge of the reed or the air, pro- duces a musical note, dependent for its pitch ou the length of the spring, its quality being determined to a great ex- tent by the length and form of the pipe or bell within which the reed is placed. When the vibrating spring does not strike the edge of the reed, but the air, we have what is called the free reed, -similar to what is in use in the harmonium. To describe the pitch of an organ- pipe, terms are used derived from the standard length of an opeu month-pipe of that pitch. The largest pipe in use is the 3'-'-feet C, which is an octave below the lowest C of the modern piano-forte, or two octaves below the lowest C on the manuals and pedal of the organ : any pipe producing this note is called a 3'2-feet C pipe, whatever its actual length may be. By a 32-feet or IC-feet stoj), we mean that the pipe" which speaks on the lowest C ou which that stop appears has a 32-feet or a 16-feet tone.
" The stops of an oigan do not always produce the note properly belonging to the key struck; sometimes they give a note an octave, or, iu the pedal-organ, even two oc- taves lower, and souietiuies one of the harmonics higher in pitch. Compound or mixture stops have several pipes to each key, corresponding to the different harmonics of the ground-tone. 'I'here is an endless variety in the num- ber and kinds of stops in different organs; some are and some are not continued through the whole rauge of manual or pedal. Some of the more important stops get the name of ojien or stopjied iJia)iason (a term which implies that they extend thruiighout the whole compass of the clavier) ; they are for the most part 16-feet, some- times 32-feet stops ; the open diapason chiefly of metal, the close chiefly of wood. The dulciana is an S-feet manual stop, of small diameter, so called from the sweetness of its tone. Among the reed-stops are the clarion, oboe, bassoon, and vox Intmana, deriving their names from real or fancied resemblances to these instruments and to the human voice. Of the compound -stops, the most prevalent in Britain is the sesqnialtera, consislins: of four or Ave ranks of open metal pipes, often a ITth, 19th, 22d, 26th, and 29th from the ground-tone. The resources of the organ are further increased by appliances called couplers, by which a second clavier and its stops can be brought into play or the same clavier can be united to itself in the octave below or above" (Chambers).
Instruments of a rude description, comprising more or less the principle of the organ, seem to have existed early. But they were much smaller in size, and they were supplied with wind in various ways. At first a per- son was emploj'ed to blow into the pipes ; later, to avoid this difRculty, a leathern wind-pouch was attached to the instrument, which pouch was worked by being held under the arm {tibia utricularia) ; then, for larger in- struments, water-power was used to compress the air in a suitable receptacle {pryanum hydraulicum) ; and, final- ly (some say earlier), the bellows {urganum p7teu- maticinn) was employed. Besides these large in- struments there was also a small portable organ, sometimes called a " pair of Begals," formerly in use, and this was occa- sionally of such a size as to admit of its being car- ried in the hand and in- flated by the player ; one of these is represented among the sculptures in the cornice of St. John's,
Portable Organ.
ORGAN
425
ORGAN
Cirencester, and another on the crosier of William of Wykeham, at Oxford.
Nero greatly admired the water-organ (Siieion. c. 41 : " Keliquam dici partem per organa hydraulica novi et ignoti generis circumdixit"). In ecclesiastical history pope Vitalian I figures as the introducer of the organ, and the date assigned is A.D. G6t3. St. Augustine and Isidore of Seville serve as authority for this statement. It appears, however, from the records of the Spanish Church, that the organ was used there two centuries previous to this date. In Africa the organ had been in common use for some time previous, and it is from that country probably that is was introduced into Spain. In the West the organ was not common until the 10th century. St. Aldhelm, who died A.D. 709, describes one with golden pipes in England ; but as late as 757, when Pepin the Short received from Constantino Co- pronymus an organ as a present, it is mentioned as a great wonder. It was placed in the church of St. Cor- neille, at Compiegne, but whether that instrument was then used for ecclesiastical purposes is a matter of con- troversy. On the other hand, it is well known that Charlemagne caused an organ to be placed in the cathedral of Aix-la-Chapelle. This organ, which is described by Walafrid Strabo, was undoubtedly the same which was sent him from Constantinople by Con- stantine Michael, and of which the chronicler of St. Gall said (De Carol. M. ii, 10), "Musicorum organum praBStantissimum, quod doliis ex aere conflatis folli- l3usque taurinis per fistulas aereas mire pertlantibus ru- gitu quidem tonitrui boatum, garrulitatem vero lyrai vel cymbali dulcedine coaquabat." Organ-building was now followed in Germany with such success that in the second half of the 9th century pope John VIII got an organ and singers sent from thence to Rome through the bishop of Freysingen. In the middle of the 10th century organs became quite common in Eng- land; and, among others, the Benedictine monks of Winchester became possessed of a large organ with four hundred pipes, and twelve upper and fourteen lower bellows, requiruig seventy strong men to work them.