KEUFFEL & ESSER, New York / USA                          (1920)
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S C A L E S  of  the   K & E    » POLYPHASE «      Model 4053-2
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Front Side           [ inverse / RED ]                Back Side
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( 0 ...  8" 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 side are conversion tables and constants - given as
fractions.  Blind prints  94/94/2  are in the woods on its left
side. The slide rule came in a brown leather case.

                    Historical Remarks ...
impressum:
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© C.HAMANN     http://public.BHT-Berlin.de/hamann      05/23/14