C-THRU® RULER COMPANY, Bloomfield, CT / USA                   (1970)
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                                                       Made in Japan

S C A L E S  of the    M E D I U M   S I Z E D   RIETZ   Model »883«
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Front Side          [ inverse / RED ]                      Back Side
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K          X3
DF         X * sqrt(10)
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CF         X * sqrt(10)                           S      sin( 0.1X )
[CI]       [1/X]                                  L      -lg( 0.1X )
C          X                                      T      tan( 0.1X ) 
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D          X
A          X2

R E M A R K S :
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The CF / DF Scales are folded at  sqrt(10)   < and NOT at π >
To use the Back-Scales, the slider has to be turned  -  BUT THAN:

The L-Scale is keyed to 1/X Scale  < but [CI] is not visible !!! >
That means the result is  L = ( 1 - lgX ) = lg( 10/X ) = -lg( X/10 )

There is an open  Q U E S T I O N :  " Why this L-Scale Design ??? "

The owner of the old stationary shop told me,  that this slide rule
was distributed by the  C-THRU®  company,  BUT NO LOGO  is visible.
The SR came in a black soft plastic case without instruction sheet.

                  Historical Remarks ...
impressum:
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© C.HAMANN        http://public.BHT-Berlin.de/hamann        09/10/09