TAVERNIER-GRAVET, Paris / France                          (1920)
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S C A L E S  of  the   TAVERNIER-GRAVET             » MANNHEIM «
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Front Side                                             Back Side
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( 0 ...  25 cm Ruler )

A      X2
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B      X2                      S      sin(0.1X)   NEW GRADES (!)
                               L      lgX
C      X                       T      tan(0.1X)   NEW GRADES (!)
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D      X

R E M A R K S :                ONE FULL CIRCLE = 400 DEGREES (!)
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The TRIGONOMETRIC SCALES are  decimal-divided in  NEW GRADES (!)

"Mouse-over" the cursor to get a PopUp with Detail-Pictures ...
and observe:  sin(33.33g) = 0.5 ;  sin(100g) = 1 ;  tan(50g) = 1

This old model is made of  pear wood  with scales on  celluloid
veneer. Engraved is "MINISTERE DE LA GUERRE" (= War Department).
On its back side was a (worn-out) table with physical constants.
The front side is empty - Reserved for Reduction Scale / Ruler ?

                    Historical Remarks ...
impressum:
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© C.HAMANN     http://public.BHT-Berlin.de/hamann       06/11/10