K&E 4165 Urea Index Slide rule

This slide rule is a specail function rule built on a Mannheim frame. The rule is best described on page 246 of the K&E full line catalog from 1921. This rule is only shown in the 1921, 1922, and 1925 catalogs.


These scans are from the collection of Clark McCoy

Front side and case:


Back side of rule and slide:


Top edge of rule


Bottom edge of rule


Left end of rule