Clocks and Objects with Movement
Clocks are the oldest measuring time devices we cannot do without today. Sundials are rightly believed to be the very first instruments used to measure time: they were used in ancient Egypt before the Common Era. The Bible also mentions the sundial owned by King Ahaz who lived in 732 BCE. Some argue that clocks were first mentioned in 1100 BCE, and were described by a Chinese named Chiu Pi in his manuscripts. Still others claim that first clocks were invented in Babylon around 1000 BCE.further...
A Buddhist monk, Yi Xing, along with a government official, Liang Lingzan, created first mechanical clocks with a liquid-driven escapement movement in China in 725 BCE. Such mechanisms were hardly accurate since they still depended on the flow of liquid through an orifice to measure time.
Timepieces with a mechanical escapement appeared much later and were then mostly used in tower clocks. The first clock is believed to be installed in 1335 in Milan, Italy. The tower clocks worked due to the force exerted by a heavy weight of several hundred kilograms, attached to a long rope is coiled round a shaft. Pulled by the weight, the shaft rotated transferring the movement via cogwheels to a clock hand, which was just one in those days. Rotating intermittently in opposite directions through the force of inertia, the balance wheel with attached weights drove the clockwork mechanism in impulses, more or less evenly. With their low resistance to outside effects, the mechanism was not very accurate.
The first to replace the weight by a pendulum is believed to be the great Italian artist and engineer Leonardo da Vinci in the 15th century, however there is no precise evidence that he really made it work. Only a century later, in 1538, another Italian, Galileo Galilei, created the first pendulum, according to his biographer Viviani. The 19-year-old Galilei observed the ceiling lamp oscillating in the Pisa Cathedral. He counted the oscillations and discovered that while the period remained constant, the amplitude of the swings diminished. Those observations prompted Galileo to look deeper, and he came to the principal law of pendulum motion - isochronism (the period of oscillation is constant under low amplitudes).
However, it was not Galilei who came up with the formula describing the pendulum period, but a Dutch scientist, Christiaan Huygens, almost a century later. Huygens proved that small periods of a physical pendulum could be the same as that of an idealized mathematic model of a pendulum. Due to this isochronous oscillation, a pendulum is quite useful in timepieces with such a movement.
Apart from the pendulum, the escapement in clocks is evolved too. The escapement (escape and stroke) is a mechanism that converts the continuous rotary motion into oscillatory or reciprocating motion. It ensures that the energy in the coil or weight is spent uniformly. It is the escapement that moves the oscillating element in timepieces (a pendulum, or before it was invented, a balance wheel). The escapement regulates the movement controlling the periodic swings of the pendulum or the balance wheel. This allows the gear to make uniform rotational movements with each swing of the pendulum, moving the time reference mechanism of the clock at a constant speed.
A major breakthrough in the clocks’ manufacturing art was achieved around the 1660s by Robert Hooke who invented an anchor escapement to replace the verge escapement. Hooke’s invention was used in pendulum clocks up to the end of the 19th century. With the movement perfected, pendulum clocks developed into long-case clocks and wall-mounted pendulum clocks. Escapement mechanisms continued to improve, and clocks evolved from “the Graham escapement” to “a Synchronome free pendulum clock” invented by Shortt.
In fact, the clocks’ history is the way of innovation and progress in science. Through the evolution of this familiar gadget, we can trace the history of scientific discoveries by the world brightest minds.
Beginning from the 18th century it became fashionable to adorn a clock movement with additional musical bits and pieces: bells, pipes or reeds. In the vast majority of clocks, a barrel organ movement was used. A barrel organ was connected to the clock’s movement as well as to the animation: when the clock struck the hour or half an hour, a bell rang, and after the hour chimes a tune was started in the barrel organ, while the organ, in turn, launched the animation in the decor. This was an expensive timepiece produced by clock makers together with famous furniture firms, artists, sculptors and decorators. Clocks’ music movements’ evolution reached its peak in the 18th – 19th centuries. Long-case clocks represented an expensive work of art and a selection of high-precision mechanisms: they showed the day of the week, the date, the month, the phase of the moon. Such clocks costed a fortune.
It is believed that the oldest clock without a dial, which continue to function, was created in 1386. It is stored in Salisbury Cathedral in England. The oldest pocket watch (portable chronometer) was made of iron in about 1504 by Peter Henlein in Nuremberg, Germany. Moreover, the first batch of wristwatches was made in 1790 by the firm "Jacque Droz and Leschot" in Geneve, Switzerland.
The oldest exhibits in the Museum’s collection are - the mid-16th century English-Dutch clock and a “Lion” clock (automaton) from Augsburg, South Germany, made in 1630.
The Museum presents more than three hundred clocks and watches (long case, wall and console, mantel and table, carriage clocks and pocket watches) which give an idea of how the clocks’ manufacturing art was developed and the scientific thought progressed.