GEBR. WICHMANN, Berlin / Germany                          (1925)
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S C A L E S   of  the   W I C H M A N N            » R I E T Z «
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Front Side                                             Back Side
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( 0 ...  27 cm Ruler )

K        X3
A        X2
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B        X2                          S     sin(0.01X); sin(0.1X)
                                     L     lgX
C        X                           T     tan(0.1X)
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D        X
L        lgX

( 0 ...  28 cm Ruler )

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

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

The  slide rule  is made of pear wood  with scales  on celluloid
veneer.  On the back side are  physical  &  technical constants.
There is no model number given.  Under the slider are prints ...

      » GEBR. WICHMANN, BERLIN «     » SYSTEM RIETZ « 

There is NO MAKER LOGO  = ??? =  Made by Albert Nestler  = ??? =

                     Historical Remarks ...
impressum:
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© C.HAMANN      http://public.BHT-Berlin.de/hamann      04/22/12