��as the Posaune (Trombone), Trumpet, Vox humana, etc. Stops composed of cylindrical pipes of small diameter were likewise constructed, and made to produce the string-tone, which stops were hence called Violone (Double Bass), Viol di gamba, etc. ; and further modifications of tone were secured by either making the pipes taper upwards, as in the Spitz-flote, Gemshorn, etc., or spread out, as in the Dolcan. Thus was brought about as great a contrast in the organ ' tone-tints ' as there is between the graduated but similar tones of a photograph and the varied tints of a coloured drawing.
In the course of the I5th century the keys were reduced in size several times, as fresh contrivances for manipulating the instrument were from time to time thought of, or new re- quirements arose.
��An early improvement consisted in combining the ' long and short keys ' on one manual, and BO far reducing their size that they could be played by perhaps a couple of fingers and the thumb alternately. The manuals of the old organ in the church of St. .ZEgidien, in Bruns- wick, presented this advance; and as they are early examples, perhaps the very first to fore- shadow the modern keyboard, a representation of a few notes of one of them is here given from Praetorius.
���The naturals of the Great manual were about an inch and three quarters in width, two inches and three eighths in length in front of the short keys, while the short keys, three inches long and an inch wide, stood an inch and a half above the naturals. The keys of the second manual (Ruck-positif), curiously enough, ap- pear to have been made to a somewhat smaller gauge, the naturals being an inch and a half in
width. On this organ the intervals of a third, fourth, and fifth lay within the span of the hand, and were doubtless sometimes played.
It will be observed that the plan of lettering the keys was still followed ; but the formation of the clavier was quickly becoming so compact, well defined, and susceptible of being learnt without such assistance, that the 'alphabet' probably fell into disuse as superfluous soon after this time.
The name given to the second manual, Riick- positif, Back-choir organ, or, as it is called in England, ' Choir organ in front,' is interesting as showing that at this time the double organ (to the eye) was certainly in existence.
Franchinus Gaffurius, in his 'Theorica Musica,' printed at Milan in 1492, gives a curious en- graving of an organist playing upon an early clavier of this period, with broad keys, of which a copy is given on the opposite page (Fig. 15).
The illustration is of peculiar interest, as it represents the player using his hands to judge from their position, independently of each other in the execution of a piece of music in two distinct parts ; the melody possibly a plainsong being taken with the right hand, which appears to be proceeding sedately enough, while the left seems to be occupied in the prosecution of a contrapuntal figure, the elbows meanwhile being stretched out into almost a flying position.
The keys of the organs in the Barefooted Friars' church at Nuremberg (Rosenberger, 1475), the cathedral at Erfurt (Castendorfer, 1483), and the collegiate church of St. Blasius at Brunswick (Kranz, 1499), were less again in size than the foregoing, so that an octave was brought within about a note of its present width. The next reduction must therefore have intro- duced the scale of key still in use. Seidel (p. 10) mentions that in 1493 Rosenberger built for the cathedral at Bamberg a still larger organ than his former work at Nuremberg, and with more keys. He further observes that the manual of the organ in the Barefooted Friars' church had the upper keys of ivory and the under keys of ebony. Here then we reach a period when the keys were certainly capped with light and dark hued materials, in the manner which con- tinued to be followed up to the end of the last century, when the naturals were usually black, and the sharps and flats white. Seidel states also that all the above-named organs were provided with pedals.
The invention of the Pedals ranks among the most important improvements that were effected in the I5th century. For a long time they did not exceed an octave in compass, and consisted of the diatonic notes only  (B \f), C, D, E, F, G, A, H (B[|) and their use was for some time confined, as might have been expected, to the holding of long sustained sounds only. The manual clavier was attached to them by cords. This kind of ' pedal-action ' could only be applied conveniently when the pedals were made to a similar gauge to the manual clavier, as the clavier keys had previously been made to accord in position with the valves in the early spring-