M The “Ich Dien” rule

Data:

• Arranged by S. Waddington, Barnsley
• 12" long × 1¾" width.
• Scales:
  body top A:2 cycle log 1-10=100
  Top slide# B: 10-1-1
  Second slide C: 10-1-1
  Centre body : Gauge points : Oz D 400, 480, 516
  Third slide : D: 2 cycle log 1-10=100
  Fourth slide# E: 10-1-1
  # slides joined by brass bar
  Bottom body 0-12" measure on bevelled edge
  
• More pictures at Rod Lovett's site
• Only one other known: Oxford History of Science Museum #52599

Question:

1. ???