What technology was used in old clocks and how did they work?

Answer 1

Throughout history, time has been measured by the movement of the earth in relation to the sun and stars. The earliest timekeeper dating from as far back as 3500 BC was the shadow clock, or gnomon, a vertical obelisk that cast a shadow. Devices almost as old as the shadow clock and sundial include the hourglass (in which the flow of sand is used to measure time intervals) and the water clock or clepsydra, in which the flow of water indicates passage of time. All time-pieces require a source of power and a means of transmitting and controlling it. In today's clocks the source of power may be produced by weights, a coiled spring or an electric current. The huge planetary clock-type models, driven by water that originated during the 13th century and discovered in China, the Middle East and North America are considered to be the forerunners of today's mechanical clocks. Eventually a weight falling under the force of gravity was substituted for the flow of water. Although the exact origin of this mechanical device remains a mystery to this day, the first recorded examples date from the 14th century. An original medieval clock dating from 1386 has been fully restored and can be seen at Salisbury Cathedral in England. These clocks were not very accurate and would loose up to 15 minutes a day! Christiaan Huygens (1629-1695), the son of a Dutch diplomat, himself a gifted astronomer, was the first to develop a pendulum-driven clock which he completed on 25 December 1656. John Harrison (1693-1776) improved on the first pendulum clock, by building a pendulum made of two different metals, bronze and steel. The metals reacted differently to cold and heat and thereby overcame the negative effect of heat and cold on the pendulum's length that resulted in the clock either loosing or gaining time. Thomas Mudge (1715-94) had a very good reputation for making very intricate clocks. He developed the Marine Timekeeper in 1774 and as early as 1754 he developed the escapement, a small metal hand that regulates the swing of the pendulum. This integral part of a clock mechanism is still used today in mechanical clocks. The tall body of a long case or grandfather clock is so designed to accommodate, protect and support the mechanism. A clock requires winding every seven days. During that time the weights, pulled by gravity, sink closer and closer to the floor. A long case is needed to allow for this gradual descent, and to protect the weights in the process. This design is still used today in modern grandfather clocks, which shows how little the old technology has changed. The smaller portable clocks, known as carriage clocks, date mostly from 1812-1830. Abraham Louis Breguet is thought to be the inventor of these spring-driven, portable clocks. Mass production of clocks began in the United States after the American War of Independence and made it possible for most families to afford a clock. The electric clock was an American innovation of the early 1900's, invented by Henry E. Warren, and was followed by the quartz clock invention in 1929. New sources of power, such as sunlight and body heat are being investigated in current horological research. from www.grandfatherclocks.co.uk