KEUFFEL & ESSER, New York / USA SN = 540205 (1960)
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S C A L E S of the » POLYPHASE DUPLEX « Model 681497
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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 ; [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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ATTENTION: Scale [tan(X)] refers to the reciprocal [CI] scale.
This model is made of mahogany with scales on celluloid veneer.
The print "US" indicates a former property of the US GOVERNMENT.
It came in a brown leather case.
Historical Remarks ...
impressum:
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© C.HAMANN http://public.BHT-Berlin.de/hamann 07/13/12
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