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KEUFFEL & ESSER 4092-3 ( 10" / 25 cm Scales )
WITH A CONFUSING LL0 SCALE (*)
KEUFFEL & ESSER, Hoboken, NewJersey / USA SN = 103686 (1930)
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S C A L E S of the » LOG LOG DUPLEX « Model 4092-3
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Front Side [ inverse / RED ] Back Side
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K X3 LL0 exp(-0.1X) // exp(-0.01X)
DF πX A X2
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CF πX B X2
[CIF] [1/πX] S sin(0.1X); sin(0.01X)
[CI] [1/X] T tan(0.1X)
C X C X
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D X LL3 exp(X)
L lgX LL2 exp(0.1X)
LL1 exp(0.01X)
R E M A R K S : ( 1° = 60' ; 1' = 60" )
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The TRIGONOMETRIC SCALES are devided in MINUTES(') & SECONDS(")
S keyed to B ; T keyed to C ;
LL0 is keyed to A Scale (!!!) ; LL1, LL2 & LL3 are keyed to D
This SR is made of mahogany with scales on celluloid veneer. The
brown leather case has the inscription » LOGLOG DUPLEX/4092-3S «
One glass was broken and replaced by a home made acrylic.
A 2nd Version with F R A M E D CURSOR is in the Collection ...
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SN = 321846
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(*) R E M A R K : !!! CONFUSING !!!
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Observe LL0-Scale is keyed to A-Scale ...
exp(-0.2)=0.82; exp(-0.7)=0.5; exp(-2)=0.135 (=!!!=)
exp(-0.04)=0.960; exp(-0.07)=0.932
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