KEUFFEL & ESSER, New York / USA                       (1920)
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                                                 VERSION (A)

S C A L E S  of  the   K & E   » POLYPHASE «    Model 4053-3
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Front Side         [ inverse / RED ]               Back Side
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( 0 ...  10" Ruler )
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A       X2
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B       X2                     S       sin(0.1X); sin(0.01X)
[CI]    [1/X]                  L       lgX
C       X                      T       tan(0.1X)
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D       X
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K       X3

R E M A R K S :                   (  1° = 60' ;   1' = 60" )
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The  TRIGONOMETRIC  SCALES  are  in  MINUTES(') & SECONDS(")

S keyed to A/B ;  T keyed to C/D

This model is made of mahogany with scales on celluloid
veneer. On the back are conversion tables and constants -
given as fractions. 3/327/327 are blind printed in the woods
on its left side. The slide rule came in a black cardboard
box. The MISSING LID has to be home made ...

There is a newer (1940) Version (B) in the Collection
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Only the CURSOR has changed to metal/plastic.
557/557 are blind printed in the woods on its left side.
It came in a fine black leather case with a snap ...