The chords necessary in this part, which with its supporting bass is called the continuo, were indicated by figures; and the evanescent and delicate tones of the harpsichord; lent themselves admirably to this purpose where solo voices and instruments were concerned.
The same comments apply to the attempts sometimes made to fill out the bare places in 18thcentury clavier music. There is no doubt that such filling out was often done on a second harpsichord with stops of a very light tone; but, if it cannot be done on the modern pianoforte in a touch so light as to avoid confusion between it and the notes actually written as essential to the design, it certainly ought not to be done at all.
The greater richness of tone of the modern pianoforte is a better compensation for any bareness that may be imputed to pure two-part or three-part writing than a filling out which deprives the listener of the power to follow the essential lines of the music. The same holds good, though in a lesser degree, of the resources of the harpsichord in respect of octavestrings.
To sacrifice phrasing, and distinctness in real partwriting, to a crude imitation of the richness produced mechanically on the harpsichord by drawing 4-ft.
In the time of Bach such writing was beautifully suited to enliven the dry glitter of the harpsichord, and Bach's duets for clavier and violin seem to have been sometimes played as trios with a violoncello playing from the clavier bass.
Before that time it was based exclusively on the use of the harpsichord either as a means of supporting the other instruments or as also contributing principal parts to the combination.
Chamber-music. - Bach's and his contemporaries' combinations with the harpsichord show the natural fondness, in his day, for instruments of a tone too gentle for prominent use in large rooms, or indeed for survival in modern times.
A frequent combination was flute, violin and harpsichord (very probably with a violoncello doubling the bass), and in more than one case the violin was partly tuned lower to soften its tone.
Certain ancient stringed instruments were played with a plectrum or plucker made of the quill of a bird's feather, and the word has thus been used of a plectrum made of other material and differing in shape, and also of an analogous object for striking the strings in the harpsichord, spinet or virginal.
He endeavoured to illustrate the subject by a clavecin oculaire, or ocular harpsichord; but the treatise and the illustration were quickly forgotten.