K&E 4100/4101 Family of Slide Rules


Scale set #2: 4100 (1903-1909)

Scale set #3: 4100 (1906-1922) / 4101 (1906-1927)

Scale set #4: N4100 (1925-1960) / N4101 (1928-1949)

Inch / R = H HC V = A | Cm

= C B =