This instrument was restored to playing condition in the conservation laboratory of the Division of Musical Instruments in 1968. Typical of most French instruments, it is equipped with a shove coupler, which enables the player to operate both manuals from the lower keyboard by shoving the upper keyboard away from him. In this pushed-back position, wooden uprights (dogs) attached to the upper surface of the far ends of the lower key levers couple the two manuals and cause the upper manual keys to descend when the lower manual keys are pressed. [Illustration: 29. Stehlin harpsichord: Detail of rose.] [Illustration: 30. Stehlin harpsichord: Plan view.] _Clavichords_ Dynamic shadings are possible in the clavichord, as in the piano, through variation of finger pressure. In both, the strings are struck—by metal tangents in the clavichord and by leather or felt hammers in the piano. In the clavichord the strings extend over a soundboard bridge on the player’s right and are damped (stopped from vibrating) by strips of cloth on the left. The metal hammer (tangent) mounted in the end of the key strikes the string and continues to touch it as long as the player presses the key. The tangent, while touching the string, divides it into two segments—the segment on the right being free to vibrate, the segment on the left being damped by the cloth. When the key is released, the cloth damps the entire string. Figure 31 shows a player depressing a clavichord key (middle c). The tangent at the far end of the key lever has been raised so that it has struck the strings and has lifted them above rest position. The damping cloth on the left of this raised string can also be seen. Known as early as the 15th century, the clavichord produces tones, though limited in volume, that are very expressive and even capable of vibrato (_Bebung_). Because it lacks carrying power, the clavichord historically was a solo or practice instrument, for it could not be heard in combination with other instruments or with the voice. [Illustration: 31. Clavichord action. _Photo: Robert Lautman_.] Fretted Clavichord, _about 1700; maker unknown, Germany_ Unfretted Clavichord, _18th century; maker unknown, Germany_ The clavichord was usually housed in a rectangular case which rested upon a simple stand. The range of the earlier instruments was about four octaves. By the 18th century the range had been expanded to five octaves. The larger, later clavichords had separate strings for each key and were unfretted or _bundfrei_. Many smaller and earlier clavichords were fretted (_gebunden_), having some strings that would produce more than one pitch when struck at different points by adjacent keys.