Albert Nestler, Lahr in Baden / Germany                (1912)
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                                                  VERSION (A)

S C A L E S  of  the   NESTLER   » E L E K T R O «   Model 37
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Front Side                                          Back Side
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( 0 ...  25 cm Ruler )

     V      X * 1.75
(A)         X2
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(B)         X2                           S         sin(0.1X)
                                         S&T       arc(0.01X)
(C)         X                            T         tan(0.1X)
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(D)  Q+1    X         P-1
     U      X * 5.24
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(K)         X3
(LL2)       exp(0.1X) = keyed to SCALE A and LEFT CURSOR-MARK

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

The no-named scales are marked here with their common symbols
in brackets: (A),(B),(C),(D),(K),(LL2).

The U-Scale is folded by ( for calculating "Revol./Minute" )
    π / 60  =  0.05236
The V-Scale is folded by the "Specific Resistance of Copper"
    sRcu  =  0.0175 Ω * mm2 / m
The CU-Marks  for  "Specific Conductivity of Copper"
    sCcu  =  57.2 m / Ω * mm2  =  1 / sRcu
The 736-Mark  for
    1 PS  =  0.7355 kW

There are 3 Versions of "Model 37" in this collection:

In this VERSION (A):
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The  CURSOR HAIRLINES  are symmetrical and in the common
distance (on A-Scale) AREA/DIAMETER (on X-Scale).
The LL2-Scale is  UNDER  the CUBIC-Scale and SHIFTED so,
that CUBIC "45" is over LL2 "e".  ONLY 1 SIDE-Hairline.

In contrary to  VERSION (B) , where ...
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The  CURSOR HAIRLINES  are  NOT SYMMETRICAL  and
the LL2-Scale is placed  OVER  the CUBIC-Scale and SHIFTED,
that CUBIC "39" is under LL2 "e".  2 CURSOR SIDE-Hairlines.

And also  VERSION (C)  is different ...
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The SR is longer, has a red  1/X  and  "extended"  Scales.
The  CURSOR HAIRLINES  are symmetrical again and in the
common distance (on A-Scale) AREA/DIAMETER (on X-Scale).
The LL2-Scale is placed  OVER  the CUBIC-Scale and SHIFTED,
that CUBIC "52" is under LL2 "e".  2 CURSOR SIDE-Hairlines.

Historical Remarks ...

The slide rule is made of mahogany with scales on celluloid
veneer. On the back is a desintegrated table with constants.
The cursor's side-window was missing and had to be restored.
"MouseOver" the cursor in the picture to get DETAILED VIEWS.

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