KEUFFEL & ESSER, New York / USA     SN = 421875    (1935)
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S C A L E S  of the   » POLYPHASE DUPLEX «   Model 4088-3
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Front Side         [ inverse / RED ]            Back Side
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                            K       X3 
DF       πX                 A       X2 
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CF       πX                 B       X2
[CIF]    [1/πX]             S       sin(0.1X); sin(0.01X)     
                            T       tan(0.1X)
C        X                  [CI]    [1/X]
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D        X                  D       X 
                            L       lgX

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. It has a cursor with flanges to cover the glass
edges. The slide rule came in a brown leather case.

Historical Remarks ...

One glass was broken and replaced by a home made acrylic.

impressum:
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© C.HAMANN  http://public.BHT-Berlin.de/hamann   06/23/07