CHAPTER FOUR
Telling Time by the Water-Thief
Now we must take another backward step of thousands of years. In considering the subject of time-recording, it seems necessary to wear a pair of mental seven-league boots, for we must often pass back and forth over great periods at single strides. While men were still improving the sun-dial, its disadvantages were already recognized and search was being made for some other means of telling time.
Suppose, for example, that one had only a sun-dial about the house; how would one be able to tell time after sunset or on a dark day? How would one know the hour if he were surrounded by tall buildings or a thick growth of trees? And it might be very necessary to tell time under any of these conditions.
Then, again, merely as a question of accuracy, the sun-dial was not always reliable. It would get badly out of the way if used by travelers, since different markings were needed for different latitudes. While on shipboard the motion of the waves would cause the shadow to swing around in the most bewildering manner. Even under ideal conditions it was never absolutely exact, because the apparent motion of our steady-gaited old sun is not quite as dependable as most of us imagine.
Astronomers find that they must allow for what they call "equation of time" in order to make their calculations come out true. The question need not be discussed at this point, but it can be seen that, as humanity left its earliest care-free days and began to get busy, and hurried and anxious over its affairs, it came to feel that after all the sun-dial was not altogether sufficient for its needs.
For this reason we are now taking a third big backward step, returning, this time, not to the caveman but to ancient Babylon and Egypt, probably not less than twenty-seven hundred years ago and possibly much longer. In this way we meet the clepsydra.
The clepsydra was an interesting instrument, and it had an interesting name, which meant the "thief of water" and came from two Greek words meaning "thief" and "water"; you can trace this in our words "kleptomaniac" and "hydrant." We shall now examine a timepiece that was much more nearly a machine than was the simple shade-casting sun-dial.
The original idea was simple enough. At first, it was merely that of a vessel of water, having a small hole in the bottom, so that the liquid dripped out drop by drop. As the level within the jar was lowered, it showed the time upon a scale. Thus, if the hole were so small and the vessel were so large that it would require twenty-four hours for the water to drip away at an absolutely steady rate, it may be seen that the side of the vessel might easily have been marked with twenty-four divisions to indicate the hours. It may also be seen that the water would drip as rapidly at night or in shadow as in sunlight. And the clepsydra could be used indoors, which the sun-dial could not, although it required attention in that it must be regularly refilled and the orifice must always be kept completely open, because the slightest stoppage would retard the rate of dripping and the "clock" would run slow.
The sun, which, with the other heavenly bodies, had therefore been the sole reliance of the human race in its time-reckoning could now be ignored and the would-be timekeeper called to his aid another mighty servant from the forces of nature – that of gravitation.
The most interesting human fact, however, about the clepsydra is that it involved an entirely different conception of the marking of time. Now it was not so much a question of when as of how long. A good sun-dial set in a proper position would always indicate three o'clock when it was three o'clock, but the clepsydra might do no such thing. It would merely show how many hours had elapsed since last it was filled, and the steady drip, drip, drip of the escaping water could – and did – lower the surface quite as evenly at one time of day as at another.
We have already seen that the first purpose in marking time was merely for making appointments, but the clepsydra shows that, with its invention, mankind had already made some progress toward a new point of view. One important factor in this change was the very practical need of telling time at night, in stormy weather, or indoors, where the sun-dial could not be used. The clepsydra, on the other hand, worked equally well at any hour or place, and in all sorts of weather.
Nevertheless, it, too, proved to have certain faults. After a time, people noticed the interesting fact that water ran faster from a full vessel than from one which was nearly empty; this was, of course, because of the greater pressure. Since such a variation interfered with calculations, they hit upon the idea of a double vessel; the larger one below containing a float which rose as the vessel filled, thus marking the hours upon the scale, and the smaller one above, the one from which the water dripped, being kept constantly filled to the point of overflow.
This improved form of clepsydra opened a field of fascinating possibilities in time-recording —it gave the chance to make use of a machine. There is, perhaps, no more interesting point in studying human development than to see the steady, inevitable way in which mankind from its cave-dwelling days has tended toward machinery. Roughly, this progress may be characterized as of three stages.
First. Primitive man – an upright-standing animal, naked, unarmed, weak as compared with some creatures, slow as compared with others, clumsy as compared with still others – a creature with many physical disadvantages, but with the best brain in the animal kingdom.
Second. The tool-using man, who had begun to grasp weapons and to fashion implements, thus supplementing his natural abilities by artificial means.
Third. The machine-making man, who has fashioned to himself a mechanical "body" of incredible powers – that is to say, he has learned to intensify his own powers through artificial means which he has invented, as when he made the telescope to give himself greater vision; he has made inventions by means of which he can outrun the antelopes, outfly the birds, outswim the fishes, outgaze the eagles, and overmatch the elephants in sheer physical force – he can turn night into day, can send his voice across the continent, can strike crushing blows at a distance of many miles and can carry the movements of the stars in his pocket. Some phases of this third stage were foreshadowed when man first applied wheels and pulleys to his clepsydra.
Here, then, was water steadily raised or lowered by means of uniform dropping; here was a float whose motion was controlled by that of the water; here, in fact, was water-power with a means for applying it. Attach a cord to the float, cause it to turn a wheel by use of the pulley-principle, and the motion of the wheel would indicate the time. Still better, rig up a turning-pointer, increase its speed through the use of toothed gear-wheels, place it in front of a stationary disk divided to indicate the hours, and now the apparatus looked not unlike a modern clock. Or attach a bell and let it be caused to ring at a certain point in the motion – what was that but an alarm-clock? Ctesibus of Alexandra was the one who is believed first to have applied the toothed wheels to the clepsydra and this was about 140 B. C.
Clepsydrae were expensive of course; accurate mechanical work was never cheap until modern times. Cunning craftsmen spent their time upon costly decorations, and these water-clocks became triumphs of the jeweler's art, a gift for kings. Therefore, like the sun-dial, they drifted into Rome – that vast maelstrom of the ancient world. Imagine a great walled city of low flat-roofed buildings, with fronts and porches of great columns, a town mostly of stone and much of it of marble, gleaming white under the bright Italian sun, the streets thronged with men in tunics and togas and here and there some person of importance driving by, standing erect in his chariot drawn by four horses harnessed abreast. And statues everywhere, in the streets and about the buildings and in cool courtyards and gardens among green leaves. The ancients thought of sculpture as an outdoor thing, and where we have one statue in the streets or public places of our cities, they had a hundred. We treasure the remains of them as artistic wonders in our museums, but they put them indoors and out as common ornaments, and lived among them.
Presently we hear of the clepsydra being used in Roman law courts by command of Pompey, to limit the time of speakers. "This," says one writer of the day, "was to prevent babblings, that such as spoke ought to be brief in their speeches." It is not difficult to picture some pompous and tiresome togaed advocate, rolling out sonorous Latin syllables as he cites precedents and builds up arguments, while an unseen dropping checks the time against him, and to hear his indignant surprise – and the chuckles of his auditors – when the relentless water-clock cuts him short in the middle of some period. Martial, the Latin poet, referring to a tiresome speaker who repeatedly moistened his throat from a glass of water during the lengthy speech, suggested that it would be an equal relief to him and to his audience, if he were to drink from the clepsydra. But Roman lawyers were not guileless, and sometimes, so we are told, they tampered with the mechanical regulation or else introduced muddy water, which would run out more slowly.
This suggests one of the difficulties of the clepsydra. Still more serious was the fact that it would freeze on frosty nights. There were no Pearys among the ancient Romans; polar exploration interested them not at all; but they did spread their conquests into regions of colder weather – as when Julius Caesar mentions using the clepsydra to regulate the length of the night-watches in Britain. His keen mind noted by this means that the summer nights in Britain were shorter than those at Rome, a fact now known to be due to difference of latitude.
As late as the ninth century, a clepsydra was regarded as a princely gift. It is said, that the good caliph, Harun-al-Raschid, beloved by all readers of the "Arabian Nights," sent one of great beauty to Charlemagne, the Emperor of the West. Its case was elaborate, and, at the stroke of each hour, small doors opened to give passage to cavaliers. After the twelfth hour these cavaliers retired into the case. The striking apparatus consisted of small balls which dropped into a resounding basin underneath.
The clepsydra appears to have been used throughout the Middle Ages in some European countries, and it lingered along in Italy and France down to the close of the fifteenth century. Some of these water-clocks were plain tin tubes; some were hollow cups, each with a tiny hole at the bottom, which were placed in water and gradually filled and sank in a definite space of time.
When the clepsydra was introduced from Egypt into Greece, and later into Rome, one was considered enough for each town and was set in the market-place or some public square. It was carefully guarded by a civic officer, who religiously filled it at stated times. The nobility of the town and the wealthy people sent their servants to find out the exact time, while the poorer inhabitants were informed occasionally by the sound of the horn which was blown by the attendant of the clepsydra to denote the hour of changing the guard. This was much in the spirit of the calls of the watchmen in old England, and later in our New England, who were, in a way, walking clocks that shouted "Eleven o'clock and all's well," or whatever might be the hour.
Allowing for the fact that the clepsydra was none too accurate at the best and that its reservoir must occasionally be refilled, it can be seen that this early form of timepiece, having played its part, was ready to step off the stage when a more practical successor should arrive.
With one of its earliest successors we are familiar.
CHAPTER FIVE
How Father Time Got His Hour-Glass
Every now and then one sees a picture of a lean old gentleman, with a long white beard, flowing robes, and an expression of most misleading benignity. In spite of his look of kindly good humor, he is none too popular with the human race and his methods are not always of the gentlest. In one hand he carries the familiar scythe, and, in the other, the even more familiar hour-glass. By this we may assume that he began to be pictured in this way while the hour-glass was still in common use.
The principle of the hour-glass is so similar to that of the clepsydra, and its first use was so early, that it is somewhat of a misnomer to speak of it as a successor. About the only justification that can be made is that the clepsydra has long disappeared, while the sand-glass – if not the hour-glass – is still sold in the stores for such familiar uses as timing the boiling of eggs, the length of telephone-conversations, and other short-time needs.
Nothing could be much simpler than the hour-glass, in which fine sand poured through a tiny hole from an upper into a lower compartment. It had none of the mechanical features of the later clepsydræ; it did not adjust itself to astronomical laws like the perfected sun-dials; it merely permitted a steady stream of fine sand to pass through an opening at a uniform rate of speed, until one of the funnel-shaped bowls had emptied itself – then waited with entire unconcern until some one stood it upon its head and caused the sand to run back again.
However, it possessed some very solid advantages of its own. It would not freeze; it would not spill over; it did not need refilling; it would run at a steady rate whether the reservoir were full or nearly empty; it could be made very cheaply, and there was nothing about it to wear out.
A water-clock might be of considerable size but a sand-clock, since it required turning, must be kept small, and an hour-glass– a size small enough to carry – became popular, although its use was correspondingly limited. Thus, it naturally was assigned to Father Time to be carried before watches were available. A sun-dial simply would not answer this purpose, since the old gentleman works by night as steadily as by day.
How old is the sand-glass?
We do not know definitely, but it is said to have been invented at Alexandria about the middle of the third century B. C. That it was known in ancient Athens is certain, for a Greek bas-relief at the Mattei Palace in Rome, representing a marriage, shows Morpheus, the god of dreams, holding an hour-glass. The Athenians used to carry these timepieces as we do our watches.
Some hour-glasses contained mercury, but sand was an ideal substance, for, when fine and dry, it flows with an approximately constant speed whether the quantity is great or small, whereas, liquids descend more swiftly the greater the pressure above the opening.
Hour-glasses were introduced into churches in the early sixteenth century when the preachers were famous for their wearisome sermons. The story is told of one of these long-winded divines who, on a hot day, had reached his "tenthly" just as the restless congregation were gladdened to see the last grains of sand fall from the upper bowl. "Brethren," he remarked; "Let us take another glass," and he reversed it – "Ahem, as I was saying – " And he went on for another hour.
Other preachers, more merciful, used a half-hour glass and kept within its limits. Many churches were furnished with ornamental stands to hold the glass. These timekeepers lingered along in country churches for many years, but ceased to be in anything like general demand after about 1650.
For rough purposes of keeping time on board ship, sand-glasses were employed and it is curious to note that hour and half-hour glasses were used for this purpose in the British navy as recently as the year 1839.
The very baby of the hour-glass family was a twenty-eight second affair which assisted in determining the speed of the vessel. The log-line was divided by knots, at intervals of forty-seven feet, three inches, and this distance would go into a nautical mile as many times as twenty-eight seconds would go into an hour. When the line was thrown overboard the mariner counted the number of knots slipping through his fingers while his eyes were fixed on the tiny emptying sand-glass, and in this way so many "knots" an hour denoted the ship's speed in miles.
In the British House of Commons, even at the present time, a two-minute glass is used in the preliminary to a "division," which is a method of voting wherein the members leave their seats and go into either the affirmative or negative lobbies. While the sand is running, "division-bells" are set in motion in every part of the building to give members notice that a "division" is at hand.
It was an ancient custom to put an hour-glass, as an emblem that the sands of life had run out, into coffins at burials.
Another early means of recording time applied the principle of the consumption of some slow-burning fuel by fire. From remote ages, the Chinese and Japanese thus used ropes, knotted at regular intervals, or cylinders of glue and sawdust marked in rings, which slowly smoldered away. Alfred the Great, that noble English king of the ninth century, is said to have invented the candle-clock, because of a vow to give eight hours of the day to acts of religion, eight hours to public affairs, and eight hours to rest and recreation. He had six tapers made, each twelve inches long and divided into twelve parts, or inches, colored alternately black and white. Three of these parts were burned in one hour, making each inch represent twenty minutes, so that his six candles, lighted one after the other by his chaplains, would burn for twenty-four hours.
The Eskimos also, through the long arctic night have watched the lamp which gives both light and heat to their cold huts of snow. But all these are no more than crude conveniences, whose irregularity is evident, and there is likewise no need to do more than call attention to the effect upon fire in any form, of wind or dampness in the air. The Roman lamp-clock sheltered from the weather was the best of them all, and was the only one which long continued in civilized use.
Our chief interest in all such devices comes from the touch of poetry still remaining in the tradition of the sacred flame which must be kept forever burning, and in association of life and time with fire, in such parables as that of the Wise and Foolish Virgins. There is a reminder of this old time-keeping by fire in all that poetry and philosophy which tells of hope that still may live or of deeds that maybe done, "while the lamp holds out to burn."
Thus far, in spite of occasional glimpses of the Middle Ages and of modern times, we have dealt, for the most part, with earlier ages. Now our story must leave these behind, and thus passes the ancient world with its strange pagan civilization which was so human, so wise and so simple. It is difficult for modern Americans even to imagine existence in ancient Greece or Rome or in still more ancient Egypt and Mesopotamia – since the whole attitude toward life was so essentially different from what it is to-day.
Our debt to the ancients in this one matter of recording time is typical of that in many others. To them we owe our whole fundamental system and conception of it from the astronomy by which we measure our years and our seasons and make our appeal to the final standard of the stars, down to the arithmetic of our minutes and seconds and the very names of our months and days.
In the modern application and practical use of all this, on the other hand, we owe them nothing. They never made a clock or watch, or any like device which has more than a merely ornamental use to-day. They gave us the general plan so well that we have never bettered it, but they left later generations to work out the details. They invented the second as a division of time but they did not measure by it. They did not care to try. For them, learning was the natural right and power of the few, and the gulf between the most that was known by the few and the little that was known in general, was like the gulf between great wealth and great poverty among ourselves.
Indeed, in this age of teaching and preaching, when a thought seems to need only to be born in order to be spread abroad over the world, it is hard for us even to conceive the instinct by which men kept their learning like a secret among the initiated and felt no impulse to make known that which they knew.
Their great men thought and did wonderful things which are now the common property of us all. And their common folk lived in a fashion astonishingly primitive by comparison, in an ignorance which certainly was weakness and may somehow have been bliss.
That world of theirs is gone – the body and the spirit of it alike. And there remains to us, along with much of their art and their science, the hour-glass to symbolize that relentless flight of time which they feared but never tried to save; and the quaint sun-dial in our gardens, a memory of that worldly-wise old philosophy which counted only the shining hours.