“Metrohm, Herisau”

Data:

• I got this ruler (A), the first image, used to find the inflexion point of a potentiometric curve (of chemical solutions I suppose), with its instructions.
• There was another with strange scales with strange scales (B), but I do not know if it is used with the first one or it has other scopes and application.
• The items were found in Italy.

Question:

1. Any old chemist in the group who may help?
   Item B will be used to read values from the registration charts of a measuring instrument. Karl Kleine
   The 7.5 and 15 scales remind me of old tape recorders. David Nichols
   Metrohm still exists. Peter Killer