Apparatus for the graphic combination of notes

In the second half of the 19th century the French instrument maker Rudolph Koenig (1832-1901), born in Germany, was the outstanding specialist in making acoustic apparatus. By means of this apparatus of his making, a sketch can be made of the combined vibrations of two tuning forks with different pitches. Two tuning forks are clamped in the framework. A smoked glass plate is attached to one fork, while a curved scriber is clamped to the other tuning fork. As soon as both tuning forks have been bowed by a small rubber hammer, the tuning fork with the smoked glass plate is pulled aside. The scriber then records the pattern of the combined notes on the smoked glass plate. By placing the tuning forks perpendicular to one another, a Lissajous pattern can be obtained.