1. Although fairly early this rule shows, in some ways, the variation in the Rietz 'standard'. On this rule the log scale is on the bottom of the stock and the reverse of the slide has sin (S), tan (T) and a sin/tan (ST) scale for small angles.

2. While the trig scales on the reverse of the slide are labelled in the standard way (S, ST and T) those on the front are not.

3. The rule indicates the reason for the extra lines, conversion from Watts to Horse-Power, in the frame of the cursor.

4. The rule was provided in a leather case.