KEUFFEL & ESSER, New York / USA     SN = 577263    (1935)
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S C A L E S  of the   » POLYPHASE DUPLEX «   Model 4071-3
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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]             T      tan(0.1X); [tan(X)]
[CI]     [1/X]              ST     arc(0.01X)
C        X                  S      sin(0.1X); [cos(0.1X)]
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D        X                  D      X 
L        lgX                [DI]   [1/X]

R E M A R K S :
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[tan(X)]  keyed to [DI] ;    [cos(0.1X)]  keyed to D  (!)

This model is made of mahogany with scales on celluloid
veneer. It came in a worn-out brown leather case.

                   Historical Remarks ...
impressum:
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© C.HAMANN  http://public.BHT-Berlin.de/hamann   08/11/09