East European Studies

The development of organised, civil societies, as opposed to cultures based entirely on local agriculture, drove early attempts to standardise subunits of the day using such technologies as sundials, water clocks, and sand clocks (Boorstin 26-36). Mechanical alarm clocks were created initially to ensure that early Christians could perform their religious duties at the precisely proper times of day (Aveni 92).  Sea navigation of ever-greater distances demanded greater precision, resulting in critical technological advancements such as clocks based on the regular movement of a pendulum (Boorstin 49-53).  Further developments led to wristwatches, quartz clocks, and most recently, atomic clocks.  With each advance in technology, the day was subdivided into smaller units with greater accuracy.  At the same time it is important to understand that while sundials, clocks, and other devices were developed to keep track of hours, minutes, and seconds, it has also always been important to society to keep track of passing days.  This initially facilitated planning in agriculture, and coordination of long-term and large-scale activities (Steel 10-11).  Units of multiple days such as weeks, months, and years were developed and employed.  Calendars were developed based on the path of the Sun through the seasons, around the path of the Moon, or both.  The growth of villages into towns and cities led to calendars for the coordination of markets and trade, as well as communications and travel.  For instance, early Greek society created its own unique calendar system for both civil and religious purposes (Mikalson ix). Irregularities in the orbits of the moon and the earth, along with ongoing changes among leading religions, led to numerous reforms of the prevailing calendar system.  The Greek calendar and others influenced the Roman calendar, which transitioned into the Julian calendar.  The Julian calendar, in turn, was finally reformed into the Western Gregorian calendar that is in widespread use today (Couderc 186-188). From the critical perspective, the rich, complex history of the understanding and tracking of time continues to affect all aspects of life, on all time scales.  We still rely on nature for our food supply, and nature remains cyclical over time, and thus people continue to have keen interests in the control of standardized time.  As vividly articulated by Allen Bluedorn the possibility that time can explain other phenomena, especially human behaviour, is the scientific raison detre for studying time and caring about it (Bluedorn 6).  Finally and most fundamentally, we remain faced with the finite nature of our own lives.  Our extent of awareness and consciousness of time may have profound implications for how we choose to live our lives.  
TIME LOCATION OF THE SUN
In contemporary context, the simple question do you have the time, reflects a desire to learn the current precise moment of the current day, as denoted by todays timepieces clocks and watches. However, such a question would have been absurd in ancient times.  The time of the day was equally apparent to all, as it was given by the position of the sun in its path across the sky.  Daybreak, sunrise, noon, sunset, and darkness were the planetary events that indicated when to wake, work, eat, and sleep (Landes 1).  For cultures that have no need for precision greater than this, the position of the sun is still the method for telling time.  The central African Konso people divide the day into seven segments over our 9am-8pm interval (11 hours), where each intervals name describes a common activity of that time of day.  For example, 5pm-6pm, or kakalseema, means, when the cattle return home, an event that occurs when sunset approaches (Aveni 90-91). With practice, the daylight portion of the day can successfully be accurately determined to about twelve divisions - approximately equivalent to our hours - with just the arms and naked eyesight (Aveni 91).
TIME SUNDIALS
For greater precision in time telling, time-keeping technologies were born.  The first such technology almost certainly consisted of placing a stick vertically into the ground, and noting the progression of the shadow throughout the day (Aveni 91).  It is not clear when and where the first sundial was invented, but they were used by ancient Greeks, Romans, Druids, and other civilizations of ancient history (Cunynghame 37-38 Landes 14).  They have been in use to some degree ever since indeed wherever and whenever there is sun on the planet, a simple sundial may be utilised to tell the time of day to a reasonable precision.
Two key design elements in a simple horizontal sundial are the style, or the object designed to cast shadows, and the demarcations on the horizontal portion of the sundial that denote sub-parts of the day by the position of the shadow cast by the style.
If the sundial were designed for use at the North Pole, the style could be vertical to the ground. Otherwise, however, a sundial with a vertical style in use at other latitudes gives times, other than noon, differently at different times of the year, resulting from the tilt of the earths axis with respect to its orbital plane (Flood and Lockwood, 24).  Thus, a horizontal sundial that is to be used year-round must have its style parallel to the earths axis, which is to also say it must point (approximately) toward the north star.  This angle corresponds to the latitude of the dial (Cunynghame 35-36).
Secondly, in order for the sundial to denote hours of equal length over the course of the day, unless the sundial is in use at the North Pole, the face of the sundial must have the hours marked on it in at non-equal distances.  This is because the rate of change in the angular motion of the styles shadow over the course of a day depends upon the angle of the ground to the sun, as determined by local latitude.  Thus, a reliable sundial that divides the daylight time into equal hours must accommodate this effect.  One way to envision such a design utilizing 24 positions marking 24 hours on the face of the sundial, which is parallel to the ground, is to model 24 arcs equally dividing a sphere from one pole to the other, at the angle reflecting the latitude of the location of the dial.  The arcs cross the plane of the face of the dial at uneven intervals, corresponding to regularly spaced intervals of time during the day (Cunynghame 35-37).
According to historical and archeological evidence, ancient Greek and Roman sundials, carved from blocks of different kinds of calcareous stone, are easily distinguished from late and modern varieties by their shape and more importantly by their engraved network of hour lines and day curves.  The evidence suggests that Greek and Roman diallers preferred conical and spherical dial faces.  Greek and Roman sundials always marked the twelve seasonal hours of daylight between sunrise and sunset.  Although being mathematically calculated and being of equal length during a given day, seasonal hours length varied during the year, being the shortest at winter solstice and longest at summer solstice (Higgins 345).  The foot of the gnomon could be placed in any convenient position.  From the critical perspective, Greek and Roman sundials were reliable sources of time retrieval. With few exceptions, the day curves trace the path of the gnomon points shadow at solstices and equinoxes (three lines in all), so the accurately engraved Greek and Roman sundial served as a crude calendar (Higgins 345).  Its calendary day curves are divided by eleven hour points and connected by eleven hour lines. The first hour begins at sunrise the last hour ends at sunset.
Historians do know that the notion of seasonal hours has a long history, and they know that classical astronomers used instuments which marked seasonal changes in the position of the sun.  These practices may well have combined to imspire the design of the sundial. Vitrivius list of sundial designs includes the names of their inventors. The more familiar names are those of Hellenistic astronomers and mathematicians Apollonius, Berossos, Eudoxus, and Theodosius (Gibbs 22).  This impressive roster suggests that the sundial developed as a scientific instrument in the 4th and 3rd centuries B.C.  There are several reasons why the successful designer of dials would have to possess the talents of both a mathematician and an astronomer. As astronomer he considers the observable path of the sun on the celestial sphere. As mathematician he contrives to project that path into a shadow receiving surface.  For instance, Ptolemy considers some facts about the celestial sphere, established by Hellenistic astonomers, which were certainly of particular interest to astronomer-diallers in Graeco-Roman antiquity the size of the earth is negligible, compared to the diameter of the apparent surrounding sphere of the suns path, so that the point of gnomon on the surface of the earth mayb be considered as if it is at the ceneter of the earth the horizon halves the universe the longest of the year equals the longest night (in Gibbs 25). Such considerations simplify the problem of projecting a specific part of the path of the sun through a gnomon point onto a shadow receiving surface. Vitruvius and Ptolemy recognised that two important parameters sufficienty determined the suns path observed at any place on earth geographical latitude and obliquity of the ecliptic (Gibbs 26).  Gnomons, shadows and perhaps even primitive sundials helped to establish the value of these parameters necessary for the construction of the dials which survived through centuries.
TIME WATER CLOCKS
Other than their unequal hour lengths, which was not actually considered a drawback in ancient Greece and Rome, the more fundamental factor limiting the usefulness of telling time by the sun with sundials is that the sun is only in the sky about half of the time.  When daylight turns to night, time can be roughly determined by noting the positions of the stars as they rotate about the North Pole over the course of the evening.  Viewing the night sky in order to ascertain the time of nights has its obvious drawbacks as well, as it is impossible on a cloudy night. Even a cloudy day rarely completely obscures the position of the sun in the sky, hinting at the time of day. However, a cloudy night can be pitch-black, and was especially so in ancient times with few man-made sources lighting the darkness.
So as a complement to sundials for telling time during the day, water clocks were initially the preferred technology during the night (Cunynghame 37).  A water clock measures the passage of time by the amount of water that has fallen through a small hole in a container of water. It was found that water would drip through such a small hole at a relatively constant rate, resulting in an instrument that could mark the passage of periods of time by noting the changes in water levels in either the water source tank or in the waters destination vessel.
The first engineering challenge with a water clock is that the rate.that water drips through the hole turns out to depend in part upon the pressure from above.  A full tank causes faster dripping, while a nearly empty tank causes somewhat slower dripping.  One simple solution here was to keep an approximately constant amount of water in the tank (Cunynghame 37-38).  The better solution was to slant the walls of the vessel holding the water such that the height of the water would fall at a constant rate (Boorstin 30).  In order for the water clock to be widely adopted in Rome, where the popular sundial had established variable-length hours depending upon the day of the year, water clocks were eventually successfully developed with variable rates of drip that could be correlated to the approximate length of hours for any day of the year (Cunynghame 39-40).
Other issues with water clocks included the changing viscosity of the water caused by variable temperatures, and the tendency of water to wear bigger any hole that it is designed to drip through.  Solutions to such problems were attempted by using materials other than water (such as sand, oil, or mercury) and by employing the most durable materials available for the water to drip through.  Fire clocks were also devised, where the challenge was to find materials that would burn at standardised rates.  However, the fundamental physical reality was that a device designed for something to drip, or flow, or burn at a constant rate needed considerable human attention and maintenance (Boorstin 35 Cunynghame 45-47).
TIME SAND CLOCKS  THE HOURGLASS
Of all the variations on the water clock mentioned above, one of particular importance was the water clock where sand was utilized instead of water - otherwise recognised as the hourglass. One advantage of sand was that it would flow at temperatures where water would freeze (Boorstin 33).  However, sand is less fluid than water, so it was more difficult to calibrate with other timepieces precisely.  The sandglass also had to be built very large to measure time periods of multiple hours, or small ones had to be manually turned frequently (Boorstin 33-34).
From the historical perspective, the earliest known image of a sandglass is portrayed on Ambrogio Lorenzettis fresco, The Allegory of Good Government, painted on the walls of the council chamber in the Palazzo Pubblico of Siena around 1339 (Shenton, 52). Modern scholars might know more about the early history of sandglasses if it were known when this image was painted.  One way or the other, the sandglass was in use by the middle of the fourteenth century.  However, if the sandglass was in use by the mid-fourteenth century, then when was it actually invented The art of blowing glass developed in Syria in the first century B.C.E (Turner 164). That skill is the most sophisticated one required for the manufacture of a sandglass but, as historians of technology are well aware, even if it is technically possible for an object to be made at a given point in time, that does not necessitate it being actually manufactured then. The earliest probable date for its initial development is sometime in the twelfth century, when developments in navigation, such as the importation of the compass into Western Europe and the development of portolan maps, helped to create a flowering of trade and transportation networks.  The addition of the sandglass to this combination of technologies would have increased navigational flexibility certainly in the later Middle Ages, the sandglasss shipboard use was one of its most important functions. Whether or not it actually developed that early, however, remains a matter of conjecture.
Historians emphasise that one of the major contributions of the sandglass was in sea navigation. While at sea, in order to estimate the ships location, the sailor needed to be able to measure the ships speed of travel.  The standard technique devised was to use a heavy piece of wood that was tied to the end of a rope with knots tied into it at specific regular intervals.  With the other end of the rope safely aboard, the wood was thrown overboard.  As the rope was pulled through a sailors hands into the water, he counted the number of knots that went by while time was measured by a small sandglass, typically measuring half a minute.  The number of knots pulled indicated current speed of travel (Cunynghame 41-43 Boorstin 34).  This is the direct origin of the knot unit of speed, still in use today.
By the middle of the fourteenth century, sandglass was an established technology in use in a number of disparate locations across Western Europe, as is shown by the earliest data testifying to its existence.  While the sandglass was an important tool for sailors early on, it was by no means used exclusively for navigational purposes.  Only one of the early documents refers to sandglasses purchased particularly for shipboard use. In 13345, the clerk of the Kings ship La George, Thomas Stetesham, wrote up receipts documenting payment in Flanders for sixteen glass timekeepers, orologios vitreis, twelve at four and a half gross, and another four for five gross (Turner 152-153).  In the inventories of Charles V of France dating from 1380, a sandglass is described as suitable for use at sea, leaving it unclear whether or not this particular exemplar of it was used that way or not.  The scribes description of the sandglass in Charles Vs inventory as a large timekeeper of the sea, consisting of two large vessels full of sand implies that the sandglass was not widely in use as a household implement at the time, for otherwise the mention would not include this description of its component pieces (Turner 164). Anyone already familiar with the construction of a sandglass at the time would not have needed a description of its manufacture, as is shown by later inventories which describe the degree to which the sandglasss frame was elaborate, but omit any further functional description of the devices construction.
TIME THE VERGE ESCAPEMENT AND MECHANICAL CLOCKS
Sundials, water clocks, and sandglasses, plus other less important variations on these, were inventions that successfully divided the day or night into concrete portions of time, but the devices all had their limitations.  It took the needs of modern European Christians of the fourteenth century to motivate inventors to devise and begin to perfect the earliest mechanical clocks (Boorstin 36).  These earlier mechanical timekeeping devices did not yet have faces and dials, instead they were designed to produce sounds at certain times they were purely alarm clocks.  The times when they were designed to alarm were the Churchs prescribed daily times for prayer and other religious duties (Boorstin 36-37).
The key technology of the first mechanical clocks was the escapement.  An escapement is
nothing more than an arrangement that would regularly interrupt the force of a falling weight. The interruptor was so designed that it would alternately check and then release the force of the weight on the moving machinery of the clock. (Boorstin 38)
The verge escapement design required a weight to fall only a short distance in order for the mechanical clock to keep relatively accurate time for hours.  For the first time, there was technology for dividing any day of the year into 24 equal hours, and the ability to design clocks that could reliably mark any desired hour of each day.
The broadening popularity of the new mechanical clocks reached beyond devout Christian practitioners.  Church towers became clock towers, standardising the hour for entire communities (Boorstin 39).  Furthermore, owning a clock became a status symbol, and the members of the growing elite class of the eleventh to fourteenth centuries measured their status in part by the clocks they owned and operated (Landes 74-75).  Some clocks were designed as large and elaborately engineered machines offering impressive public mechanised entertainment on the hour, every hour, for those fortunate enough to witness it (Boorstin 44-45).  By around 1330, the variable-length hours of the sundial were completely replaced by the fixed-length modern hour as measured by clocks.  A new phrase appeared in reference to the current hour, time of the clock or oclock (Boorstin 39-40).
It was relatively simple for clocks to be designed to mark not just the top of the hour, but shorter intervals such as the half-our or quarter-hour as well.  In another key design advancement, mechanical clocks finally offered a constant visual representation of the present moment in time when they started utilizing the clock dial, which was invented by the Italian doctor and scholar Jacopo de Dondi (1290-1359) in 1344 (Boorstin 45).  The clock dial provided a standardised visualization of the time that could be understood by all, with only the limited amout of literacy necessary to decode the meaning of the hand on the dial.