Telechron, Inc., Ashland, Massachusetts, USA. Model Type E, c. early
1930's, serial no. 17.
Below are a few examples of electro-mechanical master clocks that were manufactured
around the same time as the Telechron using a partial vacuum. The first picture is a very
rare version by Clemens Reifler, Munich, Germany which is the only other fully glass
enclosed master clock I know of. The second photo is the standard Reifler enclosure which
is comprised of a copper tank with a glass 'bell jar' top. The bicycle looking pump is
actually a hand vacuum pump. It is unknown how the Telechron's tank was evacuated whether
by hand or machine operated pump. The third photo is a master clock by William
Shortt who worked with the firm of Synchronome, London, England. The wood cased clock,
made by Synchronome, is the output for the master clock, which is enclosed in a similar
type of copper tank as the Reifler.
The first photo below is a master clock by Mikhailovich Fedchenko which was the last
electromechanical master clock to be made in 1970! Fedchenko's contribution to horology
was his cycloidal pendulum which used his patented suspension spring that eliminated
cycloidal error. Why would Russia go through the expense of making in the 1970's what was
basically a 1930's technology when by this time the quartz controlled not to mention
atomic clocks were well developed? One reason offered was that the Russians were afraid of
their electronically-based clocks being wiped out in an atomic attack using a high
altitude nuclear detonation to generate a high energy EMP (electro-magnetic pulse). The
United States relied on heavy shielding. Lets hope we never find out if it works!
Fedchenko's design still relied on a metal tank for its body, but did also have a bell jar
at its bottom in addition to the top. This allowed one to use a beat plate and observe the
pendulum directly from its tip. The last photo is my example by Earl Warren of Telechron.
It differs in design from the others in that it is a floor standing model.