Page:Pratt - The history of music (1907).djvu/225

 the desire for concerted effects grew, the compass was gradually stretched to three or four octaves or even more.

In most early organs, to avoid expense, the lowest octave was usually 'short,' that is, not only without all of the semitones (or even without some of the diatonic keys), but with the keys disposed in some peculiar order so as to bring them close together. This was specially common in pedal keyboards.

The original application of the keyboard was probably to the organ proper. But it was early extended to small portative organs or 'regals,' which were very popular through the later Middle Ages; and it was on such domestic instruments that the modern measurements of the keys became established. From at least the 14th century it was also applied to the monochord, producing the rudimentary clavichord, and to some form of harp or lyre, producing the spinet, virginal and harpsichord. Finally, as the 17th century closed, it was applied to the dulcimer, producing the first form of the pianoforte. When all the artistic consequences of these applications are considered, the keyboard is seen to be most interestingly related to musical progress (see sec. 135).

102. The Organ.—Among mediæval instruments the organ was conspicuous because used in church services. At least as early as the 13th century it appeared in several forms or sizes. The largest were those permanently set up in churches as part of their fixed furniture. Next came the 'positives,' which were of moderate size and could occasionally be moved as convenience required. Next were the 'portatives,' which were small enough to be carried about in processions or applied to purely private and secular entertainment. Finally, there were still smaller forms, often called 'regals,' which were made so as to fold together, often in the shape of a large book (hence often called 'Bible regals'). It is natural to think of the larger forms as connected with the historic importance of the organ, but the portatives and regals were really more significant. While church organs were meant solely to support and intensify the unison Plain-Song or some stiff counterpoint, and were coarse and strident in tone and awkward to play, the smaller forms could be used for all sorts of tonal experiments, were often sweet in quality and relatively easy to play, being distinctly conducive