Inside these three circles, perpendicular above their center, is a small
index of the seconds of minutes. At each first minute of time, being the
fastest of all, it describes the smallest orbit. Next to this are two
other slightly larger circles divided into 30 degrees, one [rotating?]
from the right, the other from the left. These two indices are arranged
in such a fashion that the one rotating from the observer's left
completes its period 12 times during one, mean, solar-astronomical year.
The one [rotating] from the right likewise completes its cycle 12 times
during the period of one mean-synodic moon. In between these, there is
placed another small sphere, divided into 40 arbitrary parts, whose dial
does not move automatically, but is moved by hand for speeding up or
slowing down the course of the time, or of the perpendicular.