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<v Speaker 1>Welcome to the I Can't Sleep Podcast, where I help

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<v Speaker 1>you drift off one fact at a time. I'm your host,

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<v Speaker 1>Benjamin Boster, and today's episode is about clocks. A clock

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<v Speaker 1>or chronometer is a device that measures and displays time.

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<v Speaker 1>The clock is one of the oldest human inventions, meeting

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<v Speaker 1>the need to measure intervals of time shorter than the

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<v Speaker 1>natural units, such as the day, the lunar month, and

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<v Speaker 1>the year. Devices operating on several physical processes have been

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<v Speaker 1>used over the millennia. Some predecessors to the modern clock

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<v Speaker 1>may be considered clocks that are based on movement in nature.

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<v Speaker 1>A sun dials shows the time by displaying the position

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<v Speaker 1>of a shadow on a flat surface. There is a

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<v Speaker 1>range of duration timers, a well known example being the hourglass.

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<v Speaker 1>Water clocks, along with sun dials, are possibly the oldest

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<v Speaker 1>time measuring instruments. A major advance occurred with the invention

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<v Speaker 1>of the verge escapement, which made possible the first mechanical

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<v Speaker 1>clocks around thirteen hundred in Europe, which kept time with

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<v Speaker 1>oscillating time keepers like balance wheels. Traditionally, in orology the

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<v Speaker 1>study of time keeping, the term clock was used for

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<v Speaker 1>a striking clock, while a clock that did not strike

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<v Speaker 1>the hours audibly was called a timepiece. This distinction is

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<v Speaker 1>not generally made any longer. Watches and other time pieces

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<v Speaker 1>that can be carried in one's person are usually not

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<v Speaker 1>referred to as clocks. Spring driven clocks appeared during the

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<v Speaker 1>fifteenth century. During the fifteenth and sixteen centuries, clock making flourished.

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<v Speaker 1>The next development and accuracy occurred after sixteen fifty six

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<v Speaker 1>was the invention of the pendulum clock by Christian Huggins.

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<v Speaker 1>A major stimulus to improving the accuracy and reliability of

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<v Speaker 1>clocks was the importance of precise timekeeping for navigation. The

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<v Speaker 1>mechanism of a timepiece with aories of gears driven by

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<v Speaker 1>a spring or weights is referred to as clockwork. The

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<v Speaker 1>term is used for a similar mechanism not used in

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<v Speaker 1>a timepiece. The electric clock was patented in eighteen forty,

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<v Speaker 1>and electronic clocks were introduced in the twentieth century, becoming

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<v Speaker 1>widespread with a development of small battery powered semiconductor devices.

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<v Speaker 1>The time keeping element in every modern clock is a

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<v Speaker 1>harmonic oscillator, a physical object resonator that vibrates or oscillates

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<v Speaker 1>at a particular frequency. This object can be a pendulum,

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<v Speaker 1>a balance wheel, a tuning fork, a quartz crystal, or

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<v Speaker 1>the vibration of electrons and atoms as they emit microwaves,

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<v Speaker 1>the last of which is so precise that it serves

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<v Speaker 1>as the formal definition of the second. Clocks have different

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<v Speaker 1>ways of displaying the time. Analog clocks indicate time with

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<v Speaker 1>a traditional clock face and moving hands. Digital clocks display

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<v Speaker 1>a numeric representation of time. Two numbering systems are in use,

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<v Speaker 1>twelve hour time notation and twenty four hour notation. Most

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<v Speaker 1>digital clocks use electronic mechanisms in LCD, LED and VFD

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<v Speaker 1>displays for the blind and for use over telephones, Speaking

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<v Speaker 1>clocks state the time audibly in words. There are also

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<v Speaker 1>clocks for the blind that have displays that can be

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<v Speaker 1>read by touch. The word clock derives from the medieval

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<v Speaker 1>Latin word for bell, clocca, and has cognates in many

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<v Speaker 1>European languages. Clocks spread to England from the Low Countries,

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<v Speaker 1>so the English word came from the Middle Low German

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<v Speaker 1>and Middle Dutch clocca. The word is also derived from

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<v Speaker 1>the Middle English clock, Old North French clock, or Middle

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<v Speaker 1>Dutch clocca, all of which mean bell. The apparent position

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<v Speaker 1>of the sun and the sky changes over the course

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<v Speaker 1>of each day, reflecting the rotation of the earth. Shadows

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<v Speaker 1>cast by stationary objects move correspondingly, so their positions can

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<v Speaker 1>be used to indicate the time of day. A sundial

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<v Speaker 1>shows the time by displaying the position of a shadow

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<v Speaker 1>on a usually flat surface that as markings that correspond

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<v Speaker 1>to the hours. Sun dials can be horizontal, vertical, or

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<v Speaker 1>in other orientations. Sun dials were widely used in ancient times.

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<v Speaker 1>With knowledge of latitude, a well constructed sun dial can

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<v Speaker 1>measure local solar time with reasonable accuracy within a minute

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<v Speaker 1>or two. Sun dials continued to be used to monitor

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<v Speaker 1>the performance of clocks in Dily eighteen thirties. When the

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<v Speaker 1>use of the telegraph and trains standardize time and time

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<v Speaker 1>zones between cities, many devices can be used to mark

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<v Speaker 1>the passage of time without respect or reference time time

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<v Speaker 1>of day, hours, minutes, et cetera, and can be useful

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<v Speaker 1>for measuring duration or intervals. Examples of such duration timers

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<v Speaker 1>are candle clocks, incense clocks, and the hourglass. Both the

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<v Speaker 1>candle clock and the incense clock work on the same

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<v Speaker 1>principle wherein the consumption of resources is more or less constant,

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<v Speaker 1>allowing reasonably precise and repeatable estimates of time passages. In

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<v Speaker 1>the hour glass, fine sand pouring through a tiny hole

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<v Speaker 1>at a constant rate indicates an arbitrary predetermined passage of time.

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<v Speaker 1>The resource is not consumed but reused. Water clocks, along

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<v Speaker 1>with sun dials, are possibly the oldest time measuring instruments,

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<v Speaker 1>with the only exception being the day counting tally stick.

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<v Speaker 1>Given their great antiquity, where and when they first exist

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<v Speaker 1>it is not known and is perhaps unknowable. The bowl

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<v Speaker 1>shaped outflow is the simplest form of a water clock

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<v Speaker 1>and is known to have existed in Babylon and Egypt

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<v Speaker 1>around the sixteenth century b C. Other regions of the world,

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<v Speaker 1>including India and China, also have early evidence of water clocks,

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<v Speaker 1>but the earliest dates are less certain. Some authors, however,

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<v Speaker 1>write about water clocks appearing as early as four thousand

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<v Speaker 1>b C in these regions of the world. The Macedonian

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<v Speaker 1>estroemer Andronicos of Cyrus supervised the construction of the Tower

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<v Speaker 1>of the Winds and Assens in the first century BC,

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<v Speaker 1>which housed a large klepsidra inside, as well as multiple

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<v Speaker 1>prominent sundials outside, allowing it to function as a kind

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<v Speaker 1>of early clock tower. The Greek and Roman civilizations advanced

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<v Speaker 1>water clock design with improved accuracy. These advances were passed

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<v Speaker 1>on through Byzantine and Islamic times, eventually making their way

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<v Speaker 1>back to Europe independently. The Chinese developed their own advanced

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<v Speaker 1>water clocks by seven twenty five AD, passing their ideas

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<v Speaker 1>on to Korea and Japan. Some water clock designs were

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<v Speaker 1>developed independently, and some knowledge was trans insferred through the

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<v Speaker 1>spread of trade. Pre modern societies do not have the

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<v Speaker 1>same precise time keeping requirements that exist in modern industrial societies,

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<v Speaker 1>where every hour of work or rest is monitored and

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<v Speaker 1>work may start or finish at any time regardless of

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<v Speaker 1>external conditions. Instead, water clocks in ancient societies were used

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<v Speaker 1>mainly for astrological reasons. These early water clocks were calibrated

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<v Speaker 1>with a sun dial. While never reaching the level of

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<v Speaker 1>accuracy of a modern time piece, the water clock was

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<v Speaker 1>the most accurate and commonly used time keeping device for

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<v Speaker 1>millennia until it was replaced by the more accurate pendulum

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<v Speaker 1>clock in seventeenth century Europe. Islamic civilization is credited with

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<v Speaker 1>further advancing the accuracy of clocks through elaborate engineering. In

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<v Speaker 1>seven ninety seven or possibly eight o one, the Abbasid

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<v Speaker 1>Caliph of Baghdad arun Rashid presented Charlemagne with an Asian

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<v Speaker 1>elephant named abul Abbas, together with a particularly elaborate example

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<v Speaker 1>of a water clock. Pope Sylvester the Second introduced clocks

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<v Speaker 1>to northern and western Europe around one thousand eighty. The

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<v Speaker 1>first known geared clock was invented by the great mathematician, physicist,

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<v Speaker 1>and engineer Archimedes during the third century BC. Archimedes created

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<v Speaker 1>his astronomical clock, which was also a cuckoo clock, with

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<v Speaker 1>birds singing and moving every hour. It is the first

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<v Speaker 1>carolon clock as it plays music simultaneously with a person

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<v Speaker 1>blinking his eyes surprised by the singing birds. The Archimedes

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<v Speaker 1>clock works with a system of four weights, counterweights, and

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<v Speaker 1>strings regulated by a system of floats, and a water

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<v Speaker 1>container with siphons that regulate the automatic continuation of the clock.

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<v Speaker 1>The principles of this type of clock are described by

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<v Speaker 1>the mathematician and physicist Hero who says that some of

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<v Speaker 1>them work with a chain that turns a gear in

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<v Speaker 1>the mechanism. Another Greek clock, probably constructed at the time

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<v Speaker 1>of Alexander, was in Gaza. As described by A Procopius,

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<v Speaker 1>the Gaza clock was probably a medious kopaean by e

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<v Speaker 1>a building showing celestial phenomena and the time. It had

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<v Speaker 1>a pointer for the time and some automations similar to

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<v Speaker 1>the Archimedes clock. There were twelve doors opening, one every

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<v Speaker 1>hour with Hercules performing his labors the lion at nine o'clock,

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<v Speaker 1>et cetera. And at night a lamp becomes visible every

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<v Speaker 1>hour with twelve windows opening to show the time. The

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<v Speaker 1>Tang dynasty Buddhist Mung Yeshen, along with government official Leon Lingzhang,

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<v Speaker 1>made the escapement in seven twenty three or seven twenty

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<v Speaker 1>five to the workings of a water powered armillary sphere

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<v Speaker 1>and clock drive, which was the world's first clockwork escapement.

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<v Speaker 1>The Song dynasty polymath and genius Sioux Song incorporated it

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<v Speaker 1>into his monumental innovation of the astronomical clock tower of

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<v Speaker 1>Chaifung in ten eighty eight. His astronomical clock and rotating

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<v Speaker 1>armillary sphere still relied on the use of either flowing

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<v Speaker 1>water during the spring, summer, and autumn seasons or liquid

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<v Speaker 1>mercury during the freezing temperatures of winter. In Sioux Song's

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<v Speaker 1>water wheel link work device, the action of the escapement's

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<v Speaker 1>arrest and release was achieved by gravity exerted periodically as

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<v Speaker 1>a continuous flow of liquid filled containers of a limited

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<v Speaker 1>size in a single line of evolution. Sioux Song's clock

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<v Speaker 1>therefore unit the concepts of the calypsidra and the mechanical

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<v Speaker 1>clock into one device run by mechanics and hydraulics. In

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<v Speaker 1>his memorial, Siue's Song wrote about this concept, according to

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<v Speaker 1>your servant's opinion, there have been many systems and designs

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<v Speaker 1>for astronomical instruments during past dynasties, all differing from one

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<v Speaker 1>another in minor respects, but the principle of the use

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<v Speaker 1>of water power for the driving mechanism has always been

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<v Speaker 1>the same. The heavens move without ceasing, but so also

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<v Speaker 1>does water flow and fall. Thus, if the water is

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<v Speaker 1>made to pour with perfect evenness, and the comparison of

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<v Speaker 1>the rotary movements of the heavens and the machine will

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<v Speaker 1>show no discrepancy or contradiction, for the unresting follows. The

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<v Speaker 1>unceasing Song was also strongly influenced by the earlier armillary

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<v Speaker 1>sphere created by Jong Seishun nine seventy six a d

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<v Speaker 1>who also employed the escapement mechanism and used liquid mercury

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<v Speaker 1>instead of water in the water wheel of his astronomical

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<v Speaker 1>clock tower. The mechanical clockworks of Sioux's Song's astronomical tower

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<v Speaker 1>featured a great driving wheel that was eleven feet in diameter,

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<v Speaker 1>carrying thirty six scoobes, into each of which water was

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<v Speaker 1>poured at a uniform rate from the constant level tank.

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<v Speaker 1>The main driving shaft of iron, with its cylindrical necks

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<v Speaker 1>supported on iron crescent shaped bearings, ended in a pinion

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<v Speaker 1>which engaged a gear wheel at the lower end of

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<v Speaker 1>the main vertical transmission shaft. The great astronomical hydro mechanical

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<v Speaker 1>clock tower was about ten meters high, featured a clock escapement,

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<v Speaker 1>and was indirectly powered by a rotating wheel, either with

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<v Speaker 1>falling water or liquid mercury. A full sized working replica

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<v Speaker 1>of Siusong's clock exists in the Republic of China National

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<v Speaker 1>Museum of Natural Science, Taichung City. The full scale, fully

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<v Speaker 1>functional replica, approximately twelve meters in height, was constructed from

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<v Speaker 1>Siusong's original descriptions and mechanical drawings. The Chinese escapement spread

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<v Speaker 1>west and was a source for Western escapement technology. In

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<v Speaker 1>the twelfth century, al Jazarre, an engineer from Mesopotamia who

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<v Speaker 1>worked for the artuct King of Dia Bacher nasier Aldine,

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<v Speaker 1>made numerous clocks of all shapes and sizes. The most

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<v Speaker 1>reputed clocks include the elephant scribe and castle clocks, some

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<v Speaker 1>of which have been successfully reconstructed. As well as telling

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<v Speaker 1>the time, these grand clocks were symbols of the status,

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<v Speaker 1>grandeur and wealth of the Urtuk state. Knowledge of these

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<v Speaker 1>mercury escapements may have spread through Europe with translations of

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<v Speaker 1>Arabic and Spanish texts. The word horologgia was used to

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<v Speaker 1>describe early mechanical clocks, but the use of this word

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<v Speaker 1>for all time keepers conceals the true nature of the mechanisms.

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<v Speaker 1>For example, there is a record that in eleven seventy six,

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<v Speaker 1>Song Cathedral in France installed an orolodge, but the mechanism

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<v Speaker 1>used is unknown. According to Jocelyn de Bracolon, in eleven

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<v Speaker 1>ninety eight, during a fire at the abbey of Saint Edmundsbury,

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<v Speaker 1>the monks ran to the clock to fetch water. Indicating

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<v Speaker 1>that their water clock had a reservoir large enough to

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<v Speaker 1>help extinguish the occasional fire. The word clock, which gradually

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<v Speaker 1>supersedes ourolodge, suggests that it was the sound of bells

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<v Speaker 1>that also characterized the prototype mechanical clocks that appeared during

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<v Speaker 1>the thirteenth century in Europe. In Europe between twelve eighty

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<v Speaker 1>and thirteen twenty, there was an increase in the number

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<v Speaker 1>of references to clocks and horo lodges and church records,

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<v Speaker 1>and this probably indicates that a new type of clock

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00:20:09.160 --> 00:20:16.079
<v Speaker 1>mechanism has been devised. Existing clock mechanisms that used water

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00:20:16.200 --> 00:20:20.240
<v Speaker 1>power were being adapted to take their driving power from

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00:20:20.359 --> 00:20:26.480
<v Speaker 1>falling weights. This power was controlled by some form of

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00:20:26.599 --> 00:20:34.160
<v Speaker 1>oscillating mechanism, probably derived from existing bell ringing or alarm devices.

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<v Speaker 1>This controlled release of power the escapement marks the beginning

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<v Speaker 1>of the true mechanical clock, which differed from the previously

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<v Speaker 1>mentioned cog wheel clocks. The verge escapement mechanism appeared during

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00:20:52.480 --> 00:20:56.759
<v Speaker 1>the surge of true mechanical clock development, which did not

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<v Speaker 1>need any kind of fluid power like water or mercury

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00:21:00.640 --> 00:21:08.519
<v Speaker 1>to work. These mechanical clocks were intended for two main

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<v Speaker 1>purposes for signaling a notification and for modeling the solar system.

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<v Speaker 1>The former purpose is administrative. The latter arises naturally given

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<v Speaker 1>the scholarly interests in astronomy, science and astrology, and now

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<v Speaker 1>these subjects integrated with the religious philosophy of the time.

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<v Speaker 1>The astrolabe was used both by astronomers and astrologers, and

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<v Speaker 1>it was natural to apply a clockwork drive to the

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00:21:42.440 --> 00:21:47.160
<v Speaker 1>rotating plate to produce a working model of the solar system.

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<v Speaker 1>Simple clocks, intended mainly for notification, were installed in towers

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<v Speaker 1>and did not always require faces or hands. They would

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<v Speaker 1>have announced the canonical hours or intervals between set times

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<v Speaker 1>of prayer. Canonical hours varied in length as the times

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<v Speaker 1>of sunrise and sunset shifted. The more sophisticated astronomical clocks

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00:22:21.119 --> 00:22:25.160
<v Speaker 1>would have had moving dials or hands, and would have

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<v Speaker 1>shown the time in various time systems, including Italian hours,

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<v Speaker 1>canonical hours, and time as measured by astronomers at the time.

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<v Speaker 1>Both styles of clocks started acquiring extravagant features such as automata.

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<v Speaker 1>In twelve eighty three, a large clock was installed at

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<v Speaker 1>Dunstable Priory in Bedfordshire in southern England. Its location above

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<v Speaker 1>the rude screen suggests that it was not a water clock.

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<v Speaker 1>In twelve ninety two Canterbury Cathedral installed a great horloge.

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<v Speaker 1>Over the next thirty years there were mentions of clocks

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<v Speaker 1>at a number of ecclesiastical institutions in England, Italy and France.

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<v Speaker 1>In thirteen twenty two, a new clock was installed in Norwich,

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<v Speaker 1>an expensive replacement for an earlier clock installed in twelve

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<v Speaker 1>seventy three. This had a large two meter astronomical dial

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00:23:36.559 --> 00:23:41.960
<v Speaker 1>with automata and bells. The costs of the installation included

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00:23:42.000 --> 00:23:46.200
<v Speaker 1>the full time employment of two clock keepers for two years.

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<v Speaker 1>An elaborate water clock, the cosmic engine, was invented by

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<v Speaker 1>Sious Song, a Chinese polymath, designed and constructed in China

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00:23:59.720 --> 00:24:07.319
<v Speaker 1>and ninety two. This great astronomical hydromechanical clock tower was

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00:24:07.359 --> 00:24:11.720
<v Speaker 1>about ten meters high and was indirectly powered by a

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00:24:11.839 --> 00:24:17.680
<v Speaker 1>rotating wheel with falling water and liquid mercury, which turned

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00:24:17.720 --> 00:24:27.000
<v Speaker 1>an armillary sphere capable of calculating complex astronomical problems. In

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<v Speaker 1>Europe there were the clocks constructed by Richard of Wallingford

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<v Speaker 1>and Albans by thirteen thirty six and by Giovanni de

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<v Speaker 1>Dundi and Padua from thirteen forty eight to thirteen sixty four.

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<v Speaker 1>They no longer exist, but detailed descriptions of their design

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00:24:47.839 --> 00:24:54.519
<v Speaker 1>and construction survive, and modern reproductions have been made. They

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<v Speaker 1>illustrate how quickly the theory of the mechanical clock had

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<v Speaker 1>been translated into practical constructions, and also that one of

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<v Speaker 1>the many impulses to their development had been the desire

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<v Speaker 1>of astronomers to investigate celestial phenomena. The Australium of Giovanni

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<v Speaker 1>Dondi de lo Lorojo was a complex astronomical clock built

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<v Speaker 1>between thirteen forty eight and thirteen sixty four in Padua,

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<v Speaker 1>Italy by the doctor and clockmaker Giovanni don de de

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<v Speaker 1>lo Rogo. The Australium had seven faces and one hundred

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00:25:37.799 --> 00:25:42.160
<v Speaker 1>in seven moving gears. It showed the positions of the Sun,

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<v Speaker 1>the Moon, and the five planets then known, as well

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<v Speaker 1>as religious feast days. The Australium stood about one meter

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<v Speaker 1>high and consisted of a seven sided brass or iron

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00:25:57.920 --> 00:26:04.759
<v Speaker 1>framework resting on seven decorative paw shaped feet. The lower

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00:26:04.839 --> 00:26:08.599
<v Speaker 1>section provided a twenty four hour dial and a large

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00:26:08.720 --> 00:26:13.599
<v Speaker 1>calendar drum showing the fixed feasts of the church, the

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00:26:13.640 --> 00:26:17.400
<v Speaker 1>movable feasts, and the position in the zodiac of the

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00:26:17.440 --> 00:26:24.160
<v Speaker 1>moon's ascending node. The upper section contained seven dials, each

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<v Speaker 1>about thirty centimeters in diameter, showing the positional data from

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<v Speaker 1>the primum mobile Venus, Mercury, the Moon, Saturn, Jupiter, and Mars.

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<v Speaker 1>Directly above the twenty four hour dial is the dial

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<v Speaker 1>of the Premium mobile, so called because it reproduces the

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<v Speaker 1>diurnal motion of the stars and the annual motion of

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<v Speaker 1>the Sun against the background of stars. Each of the

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00:26:55.440 --> 00:27:01.960
<v Speaker 1>planetary dials used complex clockwork to produce reasonably accurate models

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00:27:02.000 --> 00:27:08.160
<v Speaker 1>of the planet's motion. These agreed reasonably well both with

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00:27:08.279 --> 00:27:17.640
<v Speaker 1>ptolemaic theory and with observations. Wallingford's clock had a large

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00:27:17.799 --> 00:27:23.960
<v Speaker 1>astrolabe type dial showing the Sun, the Moon's age phase

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00:27:24.279 --> 00:27:31.319
<v Speaker 1>and node, a star map, and possibly the planets. In addition,

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00:27:31.519 --> 00:27:35.000
<v Speaker 1>it had a wheel of fortune and an indicator of

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00:27:35.039 --> 00:27:39.880
<v Speaker 1>the state of the tide. At London Bridge, bells rang

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00:27:40.039 --> 00:27:47.240
<v Speaker 1>every hour, the number of strokes indicating the time. Dundee's

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<v Speaker 1>clock was a seven sighted construction one meter high, with

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00:27:52.680 --> 00:27:58.079
<v Speaker 1>dials showing the time of day, including minutes, the motions

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00:27:58.119 --> 00:28:02.400
<v Speaker 1>of all the known planets, an automatic calendar of fixed

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<v Speaker 1>and movable feasts, and an eclipse prediction hand rotating once

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<v Speaker 1>every eighteen years. It is not known how accurate or

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<v Speaker 1>reliable these clocks would have been. They were probably adjusted

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00:28:18.839 --> 00:28:22.799
<v Speaker 1>manually every day to compensate for errors caused by wear

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00:28:22.920 --> 00:28:30.880
<v Speaker 1>and imprecise manufacture. Water clocks are sometimes still used and

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<v Speaker 1>can be examined in places such as ancient castles and museums.

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<v Speaker 1>The Salisbury Cathedral clock, built in thirteen eighty six, is

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<v Speaker 1>considered to be the world's oldest surviving mechanical clock that

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00:28:45.759 --> 00:28:53.880
<v Speaker 1>strikes the hours. Clockmakers developed their art in various ways.

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<v Speaker 1>Building smaller clocks was a technical challenge, as was improving

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00:28:59.640 --> 00:29:06.039
<v Speaker 1>accurate and reliability. Clocks could be impressive show pieces to

305
00:29:06.160 --> 00:29:12.279
<v Speaker 1>demonstrate skilled craftsmanship, or less expensive, mass produced items for

306
00:29:12.400 --> 00:29:18.799
<v Speaker 1>domestic use. The escapement, in particular, was an important factor

307
00:29:19.519 --> 00:29:24.359
<v Speaker 1>affecting the clock's accuracy, so many different mechanisms were tried.

308
00:29:28.000 --> 00:29:32.480
<v Speaker 1>Spring driven clocks appeared during the fifteenth century, although they

309
00:29:32.519 --> 00:29:38.640
<v Speaker 1>are often erroneously credited to Nuremberg watchmaker Peter Henline around

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<v Speaker 1>fifteen eleven. The earliest existing spring driven clock is the

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<v Speaker 1>Chamber clock, given to Phillip the Good Duke of Burgundy

312
00:29:49.279 --> 00:29:57.319
<v Speaker 1>around fourteen thirty, now in the Germinitious National Museum. Spring

313
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<v Speaker 1>power presented clockmakers with a new problem, how to keep

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00:30:01.480 --> 00:30:04.680
<v Speaker 1>the clock movement running at a constant rate as the

315
00:30:04.720 --> 00:30:10.039
<v Speaker 1>spring ran down. This resulted in the invention of the stack,

316
00:30:10.160 --> 00:30:13.960
<v Speaker 1>freed and the fuse in the fifteenth century, and many

317
00:30:13.960 --> 00:30:17.359
<v Speaker 1>other innovations down to the invention of the modern going

318
00:30:17.440 --> 00:30:25.640
<v Speaker 1>barrel in seventeen sixty. Early clock dials did not indicate

319
00:30:25.720 --> 00:30:30.119
<v Speaker 1>minutes and seconds. A clock with a dial indicating minutes

320
00:30:30.240 --> 00:30:36.039
<v Speaker 1>was illustrated in a fourteen seventy five manuscript by Paulus Almanus,

321
00:30:36.799 --> 00:30:42.440
<v Speaker 1>and some fifteenth century clocks in Germany indicated minutes and seconds.

322
00:30:43.960 --> 00:30:47.000
<v Speaker 1>An early record of a second's hand on a clock

323
00:30:47.200 --> 00:30:51.839
<v Speaker 1>dates back to about fifteen sixty, on a clock now

324
00:30:51.880 --> 00:30:59.759
<v Speaker 1>in the Fremers Dworff collection. During the fifteenth and sixteen centuries,

325
00:31:00.400 --> 00:31:04.799
<v Speaker 1>clock making flourished, particularly in the metal working towns of

326
00:31:04.920 --> 00:31:11.039
<v Speaker 1>Nuremberg and Augsburg and in Blois, France. Some of the

327
00:31:11.119 --> 00:31:14.920
<v Speaker 1>more basic table clocks have only one time keeping hand

328
00:31:16.039 --> 00:31:19.079
<v Speaker 1>was a dial between the hour markers being divided into

329
00:31:19.119 --> 00:31:23.200
<v Speaker 1>four equal parts, making the clocks readable to the nearest

330
00:31:23.200 --> 00:31:30.440
<v Speaker 1>fifteen minutes. Other clocks were exhibitions of craftsmanship and skill,

331
00:31:31.680 --> 00:31:39.119
<v Speaker 1>incorporating astronomical indicators and musical movements. The cross speed escapement

332
00:31:39.359 --> 00:31:44.079
<v Speaker 1>was invented in fifteen eighty four by Joste Berghe, who

333
00:31:44.119 --> 00:31:50.599
<v Speaker 1>also developed the Remintoir. Berghie's clock, was a great improvement

334
00:31:50.680 --> 00:31:54.319
<v Speaker 1>and accuracy, as they were correct to within a minute

335
00:31:54.359 --> 00:32:00.480
<v Speaker 1>a day. These clocks held the sixteenth century astronomer Tycho

336
00:32:00.599 --> 00:32:06.119
<v Speaker 1>Brahi to observe astronomical events with much greater precision than before.

337
00:32:10.119 --> 00:32:13.480
<v Speaker 1>The British had dominated watch manufacture for much of the

338
00:32:13.559 --> 00:32:18.599
<v Speaker 1>seventeenth and eighteen centuries, but maintained a system of production

339
00:32:18.759 --> 00:32:23.759
<v Speaker 1>that was geared towards high quality products for the elite.

340
00:32:23.880 --> 00:32:27.640
<v Speaker 1>Although there was an attempt to modernize clock manufacture with

341
00:32:27.759 --> 00:32:32.559
<v Speaker 1>mass production techniques and the application of duplicating tools and

342
00:32:32.640 --> 00:32:35.680
<v Speaker 1>machinery by the British Watch Company in eighteen forty three,

343
00:32:37.079 --> 00:32:39.839
<v Speaker 1>it was in the United States that this system took off.

344
00:32:43.359 --> 00:32:48.000
<v Speaker 1>In eighteen sixteen, Eli Terry and some other Connecticut clockmakers

345
00:32:48.880 --> 00:32:54.519
<v Speaker 1>developed a way of mass producing clocks by using interchangeable parts.

346
00:32:55.480 --> 00:32:59.359
<v Speaker 1>Aaron Lufkin Denison started a factory in eighteen fifty one

347
00:32:59.400 --> 00:33:05.440
<v Speaker 1>in Massachuset that also used interchangeable parts, and by eighteen

348
00:33:05.480 --> 00:33:10.480
<v Speaker 1>sixty one was running a successful enterprise incorporated as the

349
00:33:10.519 --> 00:33:12.000
<v Speaker 1>Waltham Watch Company,