PICKETT & ECKEL, Chicago, Illinois / USA                   (1945)
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S C A L E S  of  the   » ALL METAL DECI LOG LOG «         Model 2
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Front Side              [ white on black ]              Back Side
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3rdRoot(X< 1;4;7 Digits,.. >)    1/N1  1/10^0.001X
3rdRoot(X< 2;5;8 Digits,.. >)    1/N2  1/10^0.01X
3rdRoot(X< 3;6;9 Digits,.. >)    1/N3  1/10^0.1X
L     lgX                        1/N4  1/10^X
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T1    tan(0.1X)                  Explanations how to find the
T2    tan(X)                     location of the decimal point
ST    arc(0.01X)
S     sin(0.1X); cos(0.1X)       CF    X/log(e) = X/M
[CI]  [1/X]                      [CI]  [1/X]
C     X                          C     X
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D     X                          D     X; [ Co = 10s-Complement ]
sqrt( X <  ODD-No-Digits > )     N1    10^0.001X
sqrt( X < EVEN-No-Digits > )     N2    10^0.01X
                                 N3    10^0.1X
                                 N4    10^X
REMARKS:
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The CURSOR shows a  Serial(?)Number = 037843  on its bottom side.

The DF-Scale is folded at  1/M  where  e = 2.71828 = EulerConst.
M = lg(e) = 0.43429   and  1/M = ln(10) = 2.30259    IT FOLLOWS:

Using the D-Scale X, the N-Scales result in Power-of-10( X ) 
Using the DF-Scale X, the N-Scales result in Power-of-e( X ) 

Using the N-Scales X, the D-Scale result in lgX
Using the N-Scales X, the DF-Scale result in lnX

Later this idea is repeated in the famous  Slide Rule N4-ES

EXAMPLE of using [ Co = 10s-Complement ]-SCALE with the X-Scale:

   lg(0.01) = -2 = [8] - 10   ====>>>   lg( 1/N ) = [Co] - 10

Historical Remarks ...

This old model was made of magnesium alloy.  It was oxidized and
powdery on the edges and the slider was locked.  For restoration
it had to be disassembled, the oxidized layers scratched away
and VASELINE was applied to all sliding parts.

impressum:
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© C.HAMANN      http://public.BHT-Berlin.de/hamann       08/09/08