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NESTLER   » PRAEZISION «
( 25 cm with 50 cm Scales W1/W1' & W2/W2' )



Albert Nestler, Lahr in Baden / Germany                   (1912)
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S C A L E S   of  the   N E S T L E R   »PRAEZISION«    Model 27
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Front Side                                             Back Side
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( 0 ...  25 cm Ruler )

D      X
W1     sqrt(X)
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W1'    sqrt(X)                 SIN  6° .. 18°  ===read===>>  W1'
L1     lg( W1 = sqrt(X) )      SIN 19° .. 80°  ===read===>>  W2'
L2     lg( W2 = sqrt(10X) )    TAN  6° .. 17°  ===read===>>  W1'
W2'    sqrt(10X)               TAN 18° .. 45°  ===read===>>  W2'
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W2     sqrt(10X)
D'     10X
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SIN    2° .. 5°   ==read==>>  W2   ( Right Mark of Cursor Ext. )
K      X3                     ( Left  Mark of Cursor Extention )

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

Because the scales W1/W1' start at 1 and end at sqrt(10)
    and the scales W2/W2' start at sqrt(10) and end at 10
the 25 cm NESTLER has the "PRECISION" of a 50 cm slide rule !!!

This historic wooden model came in a black cardboard case.
It has a table with physical constants on its back side.
In the body under the slider is a 31 ... 53 cm ruler.

Historical Remarks ...

The slide rule came in bad shape: The slider was locked, scales
were dirty & scratched, partly broken, partly not glued.  The
cursor was from NESTLER, but not the original one: It had to be
modified with an EXTENSION to use the scales from the side too.
"MouseOver" the Cursor to get DETAILED VIEWS ...

Compare the SCALE DESIGN with
    the »NESTLER-0270«,
    the »WICHMANN-1417« ( made by A.N. = Albert Nestler),
    the POST-1442 » Dual 10"/5" POCKET-SR «,
    the FABER-CASTELL »COLUMBUS/A.Rohrberg« and
    the "modern" FABER-CASTELL »NOVO-DUPLEX«

P.S.:  In 2008 the ORIG.CURSOR was found:

       

impressum:
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© C.HAMANN  http://public.beuth-hochschule.de/~hamann   04/16/08