A small square piano, probably German and possibly re-built in England during the 19th century, with Prellmechanik action. Compass: B1 to f3, 55 notes. This mysterious little piano of uncertain origin and confused history is nevertheless a very interesting instrument, especially because of the action. This is, in concept, an ingeniously arranged version of the Prellmechanik even though there seem to have been problems in the practical execution and adjustment. This is the only piano in the collection having an action without escapement yet this type with its very close relative the Stossmechanik was the basis of most square pianos in most national traditions in the 18th century. In the Stossmechanik, the hammer is not carried on the keylever but is hinged to a separate fixed rail, and is a one-armed lever so arranged that it is struck near its fulcrum by the rising keylever and accelerated towards the string. As before, the travel of the key is stopped before the motion of the hammer is complete so that the hammer is free to rebound and does not 'block' on the string, preventing vibration. The practical result to the player is much the same. The Stossmechanik is the action found in the English squares of Zumpe and his many imitators. Both of these simple actions were relatively cheap and reliable to make, could be set up with considerable finesse, and had some advantages over more sophisticated actions, for example, in repetition.