K&E 4090 "Universal" Slide Rule
10" Dual slide
This slide rule was early in the K&E designs. This rule had dual slides. it was only offered in the 1901 through the 1909 catalogs. The first offering did not have a cursor. In 1906 a cursor was added and the 16" 4091 was shown.
The first two examples here are from the Bob Otnes collection. Both are prototypes. The first is made of all wood. The second is closer to a production model.
The next set of scans are from an eBay sale by Sheila Cullen.
From an eBay sale by Sheila Cullen