SYMBOLS AND GAUGE MARKS

The values of the symbols and gauge marks on the slide rule scales and on the cursors are as follows:
(Note: Do not be confused as some marks look similar, but can have different values).

Note: Not all gauge marks could be identified. Instead, where a mark is unknown, a numerical value is shown.

SymbolComment
π = 3.14159
π / 4 = 0.7854This is to aid in finding the area of a circle by the formula; A = π D2 /4
v = π/6 = 0.5236 This mark is on K scale and is used for calculating volume of sphere where V = (π/6) D3; also v = 4π/3 = 4.189 is on K where V = (4π/3) r3.
R or ρ0 or ρ = 180/π = 57.2958° The degrees in one radian
M = 1 / π = 0. 3183, or 100 / π = 31.83
C or C' = 4/π = 1.273f = 1 / 2π = 0.15915
c or C = (√ 4/π) = 1.128
C1 = (√ 40/π) = 3.568
1° = 1.745 * 10-2 = π / 180Marks for small angle calculations are usually on ST and read on C.
The sine of one minute is = 2.909 * 10-4 ; the sine of one second is = 4.848 * 10-6
' or ρ' or 9' or δ' or ζ' or Q' = minutes in a radian = 3437.74 = (180 x 60)/π If the mark ' is = 1.970, it is = 206,265 * (180/π) / 60 = 1.97 * 105 ; where, 206,265 = (180 x 60 x 60) /π
" or ρ" or 9" or δ" or ζ" or Q" = seconds in a radian = 206,265 = (180 x 60x 60)/πIf the mark " is = 1.182, it is = 206,265 * (180/π) = 1.182 * 107 ; where, 206,265 = (180 x 60 x 60) / π
ρ" or δ2 or ζ2 or Q2 = seconds in a radian (French decimal system 400) = 636,620 = (200 x 100 x 100)/π
KW or kW stands for Kilowatts. HP(*) stands for Horsepower in U.S. and Great Britain. HP(**) for Horsepower in Continental Europe.
HP(*) (value for this mark is = 1.341). Conversions are: Kilowatts (KW) times 1.341= HP(*); Ergs per Second times 1.341 times 10-10 = HP(*).
HP(**) (value for this mark is = 1.358) for HP metric.
PS1 = factor is 1.33413
PS2 = factor is 1.3599 (this is for HP metric)