How many times a day do you glance at a clock or your wristwatch? We take these small gestures for granted. Likewise how often do you consult your calender to determine a date for an appointment or engagement? Our very existence is divided into time segments. If you don’t think it is important just try being an hour late for that appointment with your boss to discuss your future with the company or forget your wife’s birthday. From the frivilous to the most solemn of occasions our lives are driven by our measurements of time. How did some of those important concepts and divisions of time come about?
The starting point of course is the Sun. Its rising and setting marked the days. So there was a natural beginning point and then you added to that the noticeable difference in the seasons as the days lengthened or shortened as the Sun lowered in the southern sky or began its ascent again after the depths of winter. The heavens is where we started to look for figuring out the passing of time and the seasons on earth. First they only measured time by the passing of the day. The earliest marking of time on a daily basis was the Sun dial which came in many different versions. The shadow cast by the Sun from a rod or other projection vertically standing would move as the Sun moved across the sky. This could be a gauge of the time. But of course the “day” and the hours varied a great deal between winter and summer. The hours were not equal because of this constant change but it gave a crude measurement. The Greeks and others had developed the Sun dial long before Rome became the dominant power in the world. But the summer hours were longer during summer and shorter in winter. Not like your digital watch you wear today. They knew this and adjusted. Mostly the Romans didn’t worry so much about “hours” but subdivided the day into four parts. The first division was simply before noon, ante meridiem, (AM) and then after midday, post meridiem (PM). Those two major segments of time were divided into morning and fore noon for AM and then afternoon, de meridie, and evening, suprema for the two time periods after midday.
The twelve hours of the day most likely came from the 12 houses of the Zodiac. Even all seven days of the week are named after the Sun, Moon and planets in our solar system. After all we could have 10 or 8 hours to the day if we wanted. It is a construct of man, not a feature of Mother Nature. These hours were “temporary” because they varied with the seasons and were not as reliable as the rising and setting of the Sun. The Sun dial was crude but reliable if the Sun was shining and did you no good at all during the night hours.
That deficiency is what lead to the development of the sand glass and the water clock. The water clock was essentially a bucket with a small hole in the bottom to drip out. They would calibrate the drip to correspond with the length of the night. You could look to see how far the water had receded and tell the rough time. They were aware of the effrects of gravity and pressure and that the less water the slower it would drip and thus the time measurements would be skewed so they learned to slant the walls of the container to increase water pressure as it diminished to offset this effect. They also realized that corrosion would distort the accuracy of the water clock and they used gems for the hole. Thus we still refer to “jewels’ in the fine watches made in Switezerland to this day. Later they developed the sand glass. That required pretty sophisticated glass making skills to mold the glass to taper to a very small opening and they had to refine the sand. You couldn’t just go to the beach and pick up a bucketful. It would be too coarse to function as intended. So they cleaned it, cooked it, dried it out until it was almost like a fine powder for use. You had the Sundial for daylight hours and the water clock or sand glass for night time. Much later the sand glass was made mostly to measure an hour. But even then you had to pick which hour. The hour from midday on the summer solistice or mid winter or something in between? They used something in between. For centuries they didn’t think of a day as a 24 hour time period the way we do. It was 12 hours segments for day and then 12 for night.
They used the waterclocks in ancient Rome to measure the time for lawyers to argue their case. They would start the clock dripping and the lawyer if he needed more time would ask to be “granted water” which meant extra time. The one big drawback to the waterclock of course was winter time and freezing temperatures. That made the sand glass more dependable year round because the sand would not freeze. Remember in winter there was no central heating in those days. Much later came the mechanical clocks with weights and pendulums.
So the next glance you make at your watch I hope you will give a nod of thanks to some very smart and inventive people that dwelled on this earth long before you were a twinkle in your daddy’s eye. They had to understand astronomy, not astrology, physics, engineering, and some pretty sophisticated geography. They knew times varied a great deal with latitude and adjusted for it. We do take all those advances for granted like they simply feel out of the sky. They didn’t, they came from the mind of man.
At this Holy time of they year I offer two thoughts for you to ponder. Quo vadis? Night Cometh.