Gerlach was a colleague of Hass in Hamburg and the instrument on which this one is based is typical of the Hamburg style. It is now in the Ringve Museum in Trondheim. It is a large, unfretted clavichord with a compass of 5 octaves, FF to f’’’, and extra 4-foot strings in the bass up to d. These give added clarity by reinforcing the first harmonic of the bass strings, and their design is so cleverly worked out that the point at which they begin is barely audible. The layout of the string-band and precise positioning of the 4-foot strings is very challenging. The pitch is A 415. The keyboard has ebony covered naturals and bone-topped yew sharps. The key-fronts have yew arcades and the key-well is also veneered with yew. There is a music desk attached to the back of the name-board. The rather plain case is painted outside, and there is a demountable stand with cabriole legs. It is 183cm long including the stand. This is a versatile and exciting clavichord suitable for music up to Haydn and early Mozart.