It once ruled the roots -[ HMM ]-

1940s (?) Keuffel & Esser (K&E) 4080-3 Log Log Duplex Trig slide rule. Before small, affordable electronic scientific calculators became popular in the 1970s, the slide rule was the workhorse of engineers and scientists everywhere.

 

For this picture, I set the cursor to the 2.25 mark on the A scale. The cursor position corresponds to 1.5 on the D scale, which equals the square root of 2.25. 1.5 is also the cube root of 3.375, the location of the cursor on the K scale.

Done