S E S S I O N S  MANTEL CLOCK Forestville, Connecticut / USA  (1900)
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The clock came in a shaky case, was not working and the pendulum was
missing. After cleaning and oiling a temporary pendulum was made out
of a FORCEPS. After hours of fine tuning the clock worked again!  To
find the right pendulum sequence, a MAGNET was placed on the forceps
and  LONG NAILS are added and adjusted until the frequence was right
and the clocktime precise. The ALARM has its own wind-up and its own
bell situated on the left side. The Alarm is triggert by a wire from
the CENTER WHEEL. The ALARM is settable by the CENTER WHEEL for 1 ..
12 hours  in the future.  The housing was cleaned, glued, nailed and
looks nice again. A HONEY GLASS CUP was placed on the magnet to show
a "real" pendulum.  Next step is to build an adjustable pendulum ...

PENDULUM  in  Theory  &  Pratice  -  A  TEST
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The  "IDEAL PENDULUM"  has its mass concentrated in a point, hanging
on a long thread of length L [m]. The full swing (tick-tack) T [sec]
is independent from its mass - but dependent from  the gravitational
constant G [ m / sec2 ] of its location:

   T = 2π * sqrt( L / G )  ===>>   L = G * ( T / 2π )2

The temporary pendulum, what gives a quite precise clock time, count
60 full swings in 50 seconds ...

   L = 9.81 [ m / sec2 ] * ( 50 [sec] / ( 2π * 60 ))2 = 0.17256 [m]

                                                      = 17.3 [cm]
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WOW!  -  This is a  pretty good result  for the construction  of the
FINAL PENDULUM:  The "MASS" (necessary for the "Momentum") has to be
located and adjustable around 17 cm from its angle-point ...

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© C.HAMANN       http://public.BHT-Berlin.de/hamann         04/27/11