This machine works just like a straight slide rule.  The circular slide introduces different ergonomics and is  more compact than a straight rule.

It has two sides:

On the front:

The dial is divided into three zones occupied by the following logarithmic scales:

Starting from the periphery:   n: number (about 35cm long)
                                                   n²: square
                                                   1/n: reciprocals of numbers

The scale of numbers is divided into two parts: one fixed and one mobile.

On the back: 

The dial is divided into five zones occupied by the following logarithmic scales:

Starting from the periphery:  n:  cubes
                                                  S:  sine
                                                  L:  logarithms
                                                  T:  tangents
                                                  S and T:   sines and tangents for small angle