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KEUFFEL & ESSER   4081-5   ( 20" / 50 cm Scales )

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KEUFFEL & ESSER, Hoboken, NewJersey / USA     SN = 409093    (1952)
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S C A L E S   of  the   » LOG LOG DUPLEX DECITRIG «    Model 4081-5
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Front Side              [ inverse / RED ]                 Back Side
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[LL02]   [exp(-0.1X)]               [LL01]  [exp(-0.01X)]
[LL03]   [exp(-X)]                  L       lgX
                                    K       X3 
DF       πX                         A       X2 
-------------------------------------------------------------------
CF       πX                         B       X2
[CIF]    [1/πX]                     T       tan(0.1X) ; [cot(0.1X)]
[CI]     [1/X]                      SRT     arc(0.01X)
C        X                          S       sin(0.1X) ; [cos(0.1X)]
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D        X                          D       X 
LL3      exp(X)                     [DI]    1/X
LL2      exp(0.1X)                  LL1     exp(0.01X)

R E M A R K S :
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The former owner  has engraved  his name  "J.W.FRECH"  on the ends.

This model  is made of  mahogany  with scales on  celluloid veneer.
Impressive  are the details:  Look e.g.  the  TOP-SIDE  of the SR !
It came without case  and detoriated  CELLULOID CURSOR-BLOCKS ...

  

                      ... Had to be replaced by home-made PVC ones.

Same "CELLULOID DISEASE"  happened also to the  DIETZGEN 1732 ...
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Celluloid, first produced in 1872, was the first used plastic world
wide.  It consists of a  mix of  cellulose nitrate  & camphor.  The
plasticizer camphor  is given off over time  and the nitrate breaks
up  under  the influence  of oxygen  & moisture  and transforms  to
nitric acid.  Both effects  destroy the material - and  the acid is
the reason why the metal of frame and spring get brittle & rusty.

                    Historical Remarks ...
impressum:
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© C.HAMANN    http://public.beuth-hochschule.de/~hamann    10/11/12