F.250 Data Sheet MJS-p-0344

Mims, Aver-O-Matic 121, 1961-1962

Serial Number or Date Stamp:

Country: USA Primary construction material: pl Case included?: no

General Description: Specialty circular slide rule

Length of 1 decade = 5 in, and overall scale length = 9 in. The largest physical dimension is 9 in.

Front Scales: [ D ] C B A 2 3/6 7 4/8 9 5/10

Back Scales:

Notes: Log scales for computing ratio of (N-m)/N; linear angular scales for finding average of up to 10 numbers; donated by Marc Mims, son of inventor Powell Mims; US patent 3,095,144; instructions included

References: Marc Mims, private communication

Date Acquired: 07/03/2024