4.16 Unidentified

This list contains rules for which to date I have not been able to positively identify their makers. (Assuming the other identifications within the collection have all been “correct.”)

Comparative Rule.

Unidentified Rule from Germany

Engraving Proportions Rule.

Printer’s Proportion Rule.

Unidentified Rule from Japan.

Total number of unidentified slide rules in the collection: 5.

Year Mat Size Case Notes
1880 wd 9.0 no nice boxwood Comparative Rule for alcohol taxation, likely from a Sikes’ hydrometer set; one side does comparative values; other side does reducing calc
1919 wd 5.0 yes 5-in pocket rule; on back: C.E. Brignell, Coblence, Germany, Sept. 1919; D&P pi symbol?
1928 ss 5.5 no Engraving Proportion Scale; sold by Art Brown & Bro. Inc. NewYork; similar item on MIT Museum page
1960 wd 12.0 no 18 inch proportions rule, used in printing, engraving; maker? American Blueprint?; A/B scales range from 1 to 30, 12 inches from 1 to 10
1970 pl 5.0 no Made in Japan; ALCO?; from my high school years