Page:A Dictionary of Music and Musicians vol 2.djvu/769

PISTON. numbers exceeded. The French horn, from the closeness of its harmonic sounds, hardly needs more than two, respectively depressing the open note a tone and a semitone: these are usually attached to a removable slide, and can be replaced by a plain metal tube. [See the woodcut under, vol. i. p. 747.] The early pistons were of complicated plan, causing several abrupt angles in the air-way, which to a certain extent interfered with the purity and freedom of the tone. Modern improvements have to a great degree removed this defect; though there still exists a prejudice against their use, especially among players of the French horn.

In the rotatory valve the vertical piston is replaced by a horizontal fourway cock, also kept in position by a spring, moved by a lever like that of a clarinet or flute, but possessing on its circumference the same pair of orifices, and establishing exactly the same connexions between tube and slide as does the piston. The rotatory valve, when really well made, is perhaps the more perfect of the two as a mechanical contrivance; but it is somewhat more liable to stick fast, and less easily accessible for cleaning than the piston-valve. The device is quite of recent invention, due in great measure to M. Adolphe Sax, and has completely superseded the older contrivance of keys, as in the key-bugle, ophicleide, and the ancient serpent. It is liable to considerable imperfections of intonation from the fact that it does not distinguish between major and minor tones and semitones; also from the different theoretical length of the valve-slides due to alterations of key or of crook. Mr. Bassett has ingeniously added to the trumpet an extra valve, which he terms the 'comma valve' or piston, and which corrects the former error; the latter must be left to the ear of the performer, and is often sadly neglected. [ W. H. S. ]

PITCH. This word, in its general sense, refers to the position of any sound in the musical scale of acuteness and gravity, this being determined by the corresponding vibration-number, i.e. the number of double vibrations per second which will produce that sound. Thus when we speak of one sound being 'higher in pitch' than another, we mean that the vibrations producing the former are more rapid than those producing the latter, so giving what is recognised as a higher sound. The general nature of this relation may be studied in works on acoustics; it is sufficient here to state that, as a matter of practice, when the exact pitch of any musical sound has to be defined, this is most properly done by stating its vibration-number.

Standard of Pitch. It becomes, then, an important practical question for the musician, what is the exact pitch corresponding to the written notes he is accustomed to use? or, to put the question in a simpler form, what is the true vibration-number attached to any one given note, say, for example, treble C ; for if this is known, the true pitch of any other note can be calculated from it by well-known rules.

This opens the vexed question of what is called the 'Standard of Pitch.' According to reason and common sense there ought to be some agreement among the musicians of the world as to what musical note should be denoted by a certain musical sign; but unfortunately there is no such agreement, and the question is therefore still undetermined. It has been much debated, but it must suffice here to state some of the more important facts that have been elicited in the discussion.

We have no positive data as to the pitch used in the earliest music of our present form, but we may arrive at some idea of it by inference. The two octaves of Pythagoras's Greek scale must have corresponded with the compass of male voices, and when Guido added the Gamma (G), one tone below the Proslambanomenos of the Greeks, we may fairly assume that it expressed the lowest note that could be comfortably taken by ordinary voices of the bass kind. This is a matter of physiology, and is known to be somewhere about 90 to 100 vibrations per second; according to which the treble C, two octaves and a fourth higher, would lie between 480 and 532.

At a later period some information of a more positive kind is obtained by organ pipes, respecting the dimensions of which evidence exists; and it is found that the pitch varied considerably, according to the nature of the music used, there being very different pitches for religious and secular purposes respectively. The inconvenience of this however seems to have been found out, and early in the 17th century an attempt was made to introduce a Mean Pitch which should reconcile the requirements of the church with those of the chamber. It was about a whole tone above the flattest, and a minor third below the highest pitch used. The effort to introduce this was successful, and the evidence shows that from this date for about two centuries, down to about the death of Beethoven, the pitch in use was tolerably uniform. Mr. Ellis gives a long list of examples taken at various dates over this period, varying for A, from 415 to 429, or for C from 498 to 515 vibrations. This is an extreme range of only about half a semitone, which, considering the imperfect nature of the means then practicable of obtaining identity and uniformity, is remarkably satisfactory. During this period lived and wrote all the greatest musicians we know, including Bach, Handel, Purcell, Haydn, Mozart, Beethoven, Weber, Schubert, and partly Spohr, Mendelssohn, and Rossini. That is to say, the heroes of music, the founders and perfecters of modern musical art, all thought out their music and arranged it to be played and sung in this pitch. This is therefore emphatically the Classical Pitch of music. And singularly enough, it agrees with the presumptive determination we have made of the pitch that must have been used in the earliest times.

But, unhappily, this satisfactory state of things was disturbed by influences arising from modern