This horizontal dial is a fine example of Erasmus Habermel's work. The hour lines are engraved on the main brass plate, and the gnomon consists of a plumb bob hanging from a curved arm. Due to the construction of the gnomon it can only be used for a certain range of latitudes although all latitudes between 0 and 90? are marked.
The back of the plate is engraved with an ingenious device. When the two index arms are adjusted symmetrically the time of sunrise and sunset in Italian and Babylonian hours, corresponding to the length of the night and of the day, can be read directly.
