1. This rule has no indication of the maker or seller.

2. The only clue to the source of the rule is the case. This has three "stars" which indicates it was sold by Davis of Derby, United Kingdom.

3. The maker's name had even been scratched away to hide the origin. In this rule it was done rather crudely - this is even a slight trace of the name. At a meeting of the United Kingdom Slide Rule Circle, where I took this rule for identification, another member had an almost identical rule where the maker's name had been erased much more "professionally".

4. The opinion was the UKSRC members is that this rule was made by Dennert and Pape. Looking carefully at the scratched out area the letter A is clearly visible though not in the image below). Dennert & Pape rules were made at Altona, Hamburg.