Time, as a separate entity, has not yet been defined in language. Definitions will be found to be merely explanations of the sense in which we use the word in matters of practical life. No human being can tell how long a minute is; only that it is longer than a second and shorter than an hour. In some sense we can think of a longer or shorter period of time, but this is merely comparative. The difference between 50 and 75 steps a minute in marching is clear to us, but note that we introduce motion and space before we can get a conception of time as a succession of events, but time, in itself, remains elusive.

In time measures we strive for a uniform motion of something and this implies equal spaces in equal times; so we here assume just what we cannot explain, for space is as difficult to define as time. Time cannot be “squared” or used as a multiplier or divisor. Only numbers can be so used; so when we speak of “the square of the time” we mean some number which we have arbitrarily assumed to represent it. This becomes plain when we state that in calculations relating to pendulums, for example, we may use seconds and inches—minutes and feet—or seconds and meters—and the answer will come out right in the units which we have assumed. Still more, numbers themselves have no meaning till they are applied to something, and here we are applying them to time, space and motion; so we are trying to explain three abstractions by a fourth! But, happily, the results of these assumptions and calculations are borne out in practical human life, and we are not compelled to settle the deep question as to whether fundamental knowledge is possible to the human mind.

What Was Man’s First Division of Time?

Evidently, man began by considering the day as a unit and did not include the night in his time-keeping for a long period. “And the evening and the morning were the first day,” Gen. i, 5; “Evening and morning and at noonday,” Ps. lv, 17, divides the day (“sun up”) in two parts. “Fourth part of a day,” Neh. ix, 3, shows another advance. Then comes, “are there not twelve hours in a day,” John xi, 9. The “eleventh hour,” Matt. xx, 1 to 12, shows clearly that sunset was 12 o’clock. A most remarkable feature of this 12-hour day, in the New Testament, is that the writers generally speak of the third, sixth and ninth hours, Acts ii, 15; iii, 1; x, 9. This is extremely interesting, as it shows that the writers still thought in quarter days (Neh. ix, 3) and had not yet acquired the 12-hour conception given to them by the Romans. They thought in quarter days even when using the 12-hour numerals! Note, further, that references are to “hours”; so it is evident that in New Testament times they did not need smaller subdivisions. “About the third hour” shows the mental attitude. That they had no conception of our minutes, seconds and fifth-seconds becomes quite plain when we notice that they jumped down from the hour to nowhere, in such expressions as “in an instant—in the twinkling of an eye.”

Before this the night had been divided into three watches (Judges vii, 19). Poetry to this day uses the “hours” and the “watches” as symbols.

This twelve hours of daylight gave very variable hours in latitudes some distance from the equator, being long in summer and short in winter. The amount of human ingenuity expended on time measures so as to divide the time from sunrise to sunset into twelve equal parts is almost beyond belief. In Constantinople, to-day, this is used, but in a rather imperfect manner, for the clocks are modern and run twenty-four hours uniformly; so the best they can do is to set them to mark twelve at sunset. This necessitates setting to the varying length of the days, so that the clocks appear to be sometimes more and sometimes less than six hours ahead of ours. A clock on the tower at the Sultan’s private mosque gives the impression of being out of order and about six hours ahead, but it is running correctly to their system. Hotels in Constantinople often show two clocks, one of them to our twelve o’clock noon system. Evidently the Jewish method of ending a day at sunset is the same and explains the command, “let not the sun go down upon thy wrath,” which we might read, “do not carry your anger over to another day.”

This simple line of steps in dividing the day and night is taken principally from the Bible because every one can easily look up the passages quoted and many more, while quotations from books not in general use would not be so clear.

How Did Man Begin to Measure Time?

Now, as to the methods of measuring time, we must use circumstantial evidence for the prehistoric period. The rising and the going down of the sun—the lengthening shadows, etc., must come first, and we are on safe ground here, for savages still use primitive methods like setting up a stick and marking its shadow so that a party trailing behind can estimate the distance the leaders are ahead by the changed position of the shadow. Men notice their shortening and lengthening shadows to this day. When the shadow of a man shortens more and more slowly till it appears to be fixed, the observer knows it is noon, and when it shows the least observable lengthening then it is just past noon. Now, it is a remarkable fact that this crude method of determining noon is just the same as “taking the sun” to determine noon at sea. Noon is the time at which the sun reaches his highest point on any given day.

How Is the Time Calculated at Sea?

At sea this is determined generally by a sextant, which simply measures the angle between the horizon and the sun. The instrument is applied a little before noon and the observer sees the sun creeping upward slower and slower till a little tremor or hesitation appears, indicating that the sun has reached his height—noon. Oh! you wish to know if the observer is likely to make a mistake? Yes, and when accurate local time is important, several officers on a large ship will take the meridian passage at the same time and average their readings, so as to reduce the “personal error.” All of which is merely a greater degree of accuracy than that of the man who observes his shadow.

The gradual development of the primitive shadow methods culminated in the modern sun-dial. The “dial of Ahas” (Isa. xxxviii, 8), on which the sun went back ten “degrees,” is often referred to, but in one of the revised editions of the Bible the sun went back ten “steps.” This becomes extremely interesting when we find that in India there still remains an immense dial built with steps instead of hour lines.

In a restored flower garden, within one of the large houses in the ruins of Pompeii, may be seen a sun-dial of the Armillary type, presumably in its original position. It looks as if the plane of the equator and the position of the earth’s axis must have been known to the maker.

Both these dials were in use before the beginning of our era and were covered by the great eruption of Vesuvius in 79 A.D., which destroyed Pompeii and Herculaneum.

Modern sun-dials differ only in being more accurately made and a few “curiosity” dials added. The necessity for time during the night, as man’s life became a little more complicated, necessitated the invention of time machines. The “clepsydra,” or water-clock, was probably the first. A French writer has dug up some old records putting it back to Hoang-ti 2679 B.C., but it appears to have been certainly in use in China in 1100 B.C., so we will be satisfied with that date. In presenting a subject to the young student it is sometimes advisable to use round numbers to give a simple comprehension and then leave him to find the overlapping of dates and methods as he advances. Keeping this in mind, the following table may be used to give an elementary hint of the three great steps in time measuring.

Shadow time, 2000 to 1000 B.C.

Dials and water-clocks, 1000 B.C. to 1000 A.D.

Clocks and watches, 1000 to 2000 A.D.

Gear-wheel clocks and watches have here been pushed forward to 2000 A.D., as they may last to that time, but no doubt we will supersede them. At the present time science is just about ready to say that a time measurer consisting of wheels and pinions—a driving power and a regulator in the form of a pendulum or balance, is a clumsy contrivance and that we ought to do better very soon.

It is remarkable how few are aware that the simplest form of sun-dial is the best, and that, as a regulator of our present clocks, it is good within one or two minutes. No one need be without a “noon-mark” sun-dial; that is, every one may have the best of all dials. Take a post or any straight object standing “plumb,” or best of all the corner of a building. In the case of the post, or tree trunk, a stone (shown in solid black) may be set in the ground; but for the building a line may often be cut across a flagstone of the footpath. Many methods may be employed to get this noon mark, which is simply a north and south line: Viewing the pole star, using a compass (if the local variation is known) or the old method of finding the time at which the shadow of a pole is shortest. But the best practical way in this day is to use a watch set to local time and make the mark at 12 o’clock.

On four days of the year the sun is right and your mark may be set at 12 on these days, but you may use an almanac and look in the column marked “mean time at noon” or “sun on meridian.” For example, suppose on the bright day when you are ready to place your noon mark you read in this column 11.50, then when your watch shows 11.50 make your noon mark to the shadow and it will be right for all time to come. Owing to the fact that there are not an even number of days in a year, it follows that on any given yearly date at noon the earth is not at the same place in its elliptical orbit, and the correction of this by the leap years causes the equation table to vary in periods of four years. The centennial leap years cause another variation of 400 years, etc., but these variations are less than the error in reading a dial.

How Did Men Tell Time When the Sun Cast No Shadows?

During the night and also in cloudy weather the sun-dial was useless, and we read that the priests of the temples and monks of more modern times “went out to observe the stars” to make a guess at the time of night. The most prominent type after the shadow devices was the “water-clock” or “clepsydra,” but many other methods were used, such as candles, oil lamps, and in comparatively late times, the sand-glass. The fundamental principle of all water-clocks is the escape of water from a vessel through a small hole. It is evident that such a vessel would empty itself each time it is filled in very nearly the same time. The reverse of this has been used, as shown in the picture of the Time-boy of India. He sat in front of a large vessel of water and floated a bronze cup having a small hole in its bottom in this large vessel, and as the water ran in through the hole the cup sank. The boy then fished it up and struck one or more blows on it as a gong. This he continued and a rude division of time was obtained—while the boy kept awake!

The most interesting of all water-clocks was undoubtedly the “copper jars dropping water,” in Canton, China, where it can still be seen. Referring to the picture herewith and reading the four Chinese characters downwards the translation is “Canton City.” To the left and still downwards, “Hon-woo-et-low,” which is, “Copper jars dropping water.” Educated Chinamen inform me that it is over 3000 years old. The little open building or tower in which it stands is higher than surrounding buildings. It is, therefore, reasonably safe to state that the Chinese had a weather and time station over 1000 years before our era.

It is a 12-hour clock, consisting of four copper jars partially built in masonry forming a stair-like structure. Commencing at the top jar each one drops into the next downward until the water reaches the solid bottom jar. In this lowest one a float, “the bamboo stick,” is placed and indicates the height of the water, and thus in a rude way gives the time. It is said to be set morning and evening by dipping the water from jar 4 to jar 1, so it runs 12 hours of our time. What are the uses of jars 2 and 3, since the water simply enters them and drips out again? No information could be obtained, but I venture an explanation and hope the reader can do better, as we are all of a family and there is no jealousy. When the top jar is filled for a 12-hour run it would drip out too fast during the first six hours and too slow during the second six hours, on account of the varying “head” of water. Now, the spigot of jar 2 could be set so that it would gain water during the first six hours, and lose during the second six hours, and thus equalize a little by splitting the error of jar 1 in two parts. Similarly, these two errors of jar 2 could be again split by jar 3 making four small variations in lowest jar, instead of one large error in the flow of jar 1. This could be extended to a greater number of jars, another jar making eight smaller errors.

The best thing the young student could do at this point would be to grasp the remarkable fact that the clock is not an old machine, since is covers only the comparatively short period from 1364 to the present day. Compared with the period of man’s history and inventions it is of yesterday. Strictly speaking, as we use the word clock, its age from De Vick to the modern astronomical is only about 540 years. If we take the year 1660, we find that it represents the center of modern improvements in clocks, a few years before and after that date includes the pendulum, the anchor and dead beat escapements, the minute and second hands, the circular balance and the hair spring, along with minor improvements. Since the end of that period, which we may make 1700, no fundamental invention has been added to clocks and watches. This becomes impressive when we remember that the last 200 years have produced more inventions than all previous known history—but only minor improvements in clocks! The application of electricity for winding, driving, or regulating clocks is not fundamental, for the time-keeping is done by the master clock with its pendulum and wheels, just as by any grandfather’s clock 200 years old. This broad survey of time measuring does not permit us to go into minute mechanical details.

Scattered references in old writings make it reasonably certain that from about 1000 A.D. to 1300 A.D. bells were struck by machines regulated with this verge escapement, thus showing that the striking part of a clock is older than the clock itself. It seems strange to us to say that many of the earlier clocks were strikers only, and had no dials or hands, just as if you turned the face of your clock to the wall and depended on the striking for the time.

A good idea of the old church clocks may be obtained from the picture herewith. Tradition has followed it down as the “English Blacksmith’s Clock.” It has the very earliest application of the pendulum. The pendulum is less than 3 inches long and is hung on the verge, or pallet axle, and beats 222 per minute. This clock may be safely put at 250 years old, and contains nothing invented since that date. Wheels are cast brass and all teeth laboriously filed out by hand. Pinions are solid with the axles, or “staffs,” and also filed out by hand. It is put together, generally by mortise, tenon and cotter, but it has four original screws all made by hand with the file. How did he thread the holes for these screws? Probably made a tap by hand as he made the screws. But the most remarkable feature is the fact that no lathe was used in forming any part—all staffs, pinions and pivots being filed by hand. This is simply extraordinary when it is pointed out that a little dead center lathe is the simplest machine in the world, and he could have made one in less than a day and saved himself weeks of hard labor. It is probable that he had great skill in hand work and that learning to use a lathe would have been a great and tedious effort for him. So we have a complete striking clock made by a man so poor that he had only his anvil, hammer and file. The weights are hung on cords as thick as an ordinary lead-pencil and pass over pulleys having spikes set around them to prevent the cords from slipping. The weights descend 7 feet in 12 hours, so they must be pulled up—not wound up—twice a day. The single hour hand is a work of art and is cut through like lace. Public clocks may still be seen in Europe with only one hand. Many have been puzzled by finding that old, rudely made clocks often have fine dials, but this is not remarkable when we state that art and engraving had reached a high level before the days of clocks.

This picture shows the machinery necessary to operate a large modern tower clock.

The mechanism is held in place and confined entirely within a cast-iron structure which is firmly bolted to the floor. The wheels are composed of bronze, the pinions of steel (hardened) and the gears are machine cut. At the front of the clock is a small dial which enables one to tell exactly the position of the hands on the outside dials, and there is also a second hand to permit of very close regulation and adjustment.

Three ways are provided for the regulation. First by a knurled screw at the top of bed frame. Second by a revolving disc at the bottom of the pendulum ball. Very often by either of these two methods it is impossible to bring the clock to fractional seconds, and in order to permit of a nicety of adjustment there is a cup fitted at the top of the ball so that by inserting or taking out lead pellets, the rating can be brought to absolute time.

Where Does the Day Begin?

To understand this subject we must first appreciate that a day as we think of it is a division of time made by man for the purpose of his own reckoning. So far as the beginning of day is concerned, it begins at a different place in the world every hour; yes, every minute and every second in the day. As, however, the distance in feet where the day begins from one minute to another is so short that we can hardly notice it in such short measurements of time, we will look at the answer to the question from hour to hour. When you understand the subject from that point you can yourself see that the day actually begins at a different point of the earth every minute and every second of time.

How Much of the Earth Does the Sun Shine on at One Time?

The sun is shining on some part of the earth all the time and the shining of the sun makes the difference between day and night. Wherever the sun is shining it is day-time, and where the sun is not shining it is night-time.

To illustrate we will make use of an ordinary orange and a lighted gas jet. Let us take a long hat-pin and stick it through the orange from stem to stem. Now hold the orange by the ends of the hat-pin up before the lighted gas jet. You will notice that one-half of the orange is lighted, while the other half is dark. Of course, it is the half of the orange away from the light that is dark. Now, revolve the orange slowly on the hat-pin axis toward the light. When you have turned the orange half way round the part that was formerly dark is now lighted up and the other part is now dark.

Now examine closely and you will see that just one-half of the orange is lighted at one time and the other half is dark. You revolve the orange in front of the light slowly and a portion of the surface of the orange is always coming into the light, while a corresponding portion of it on the opposite side is constantly going into the dark. In other words, whatever the speed at which you revolve the orange toward the light, one-half of it is always light and the other half is always dark.

This is exactly what happens in the relation of the earth to the sun every day. One-half of the earth, which is continually revolving on its axis, is facing the sun, and is, therefore, in the daylight, while the other half of the earth’s surface is in darkness, because the light from the sun does not strike any portion of it. If the earth did not revolve one-half of it would always be in day-time, while the other half would be continually having night-time. As the earth is always moving or revolving the half where it is day-time is constantly changing, so that the day is beginning on one-half of the earth’s surface every second of the day. Actually, of course, then, if you live on the east side of town day begins with you a little sooner than with your chum who lives on the west side of town. We have come to measure the beginning of day as sunrise and the beginning of night as sunset, wherever we happen to be.

For convenience in setting clocks and in measuring time we do not take into consideration these very slight differences in the rising and setting of the sun, but set our clocks all alike in different parts of the same town or city to avoid confusion. In fact, in order to overcome the difficulties and confusions arising in reckoning the time of the clock in different localities, and still keep the beginning of what we call day-time constant with the hands of the clock, we have agreed upon what we call standard time. We agreed upon this system of fixing standard time because the actual sun time by which people set their clocks up to a few years ago led to so many mistakes in catching trains, keeping engagements and other misunderstandings where the question of time was involved. Then when this system of standard time was adopted the confusion became even worse, and the mistakes and misses more numerous, because some people insisted on setting their clocks to standard time and others insisted on sticking to the old sun time schedule. So you could never tell by looking at the clock what time it really was unless they put a sign on the clock saying what kind of time they were going by. Finally, however, most of the people came to appreciate that it would be a good idea to use one uniform system of setting the clocks and of having them in harmony in a sense with the other clocks in the world, and the adoption of the standard time plan became universal. To make this system practical and effective, certain points about equally distant from each other were selected, at which point

Where Is the Hour Changed?

the hour would change for all points within that zone. Under this system all timepieces in any one zone point to the same hour. So the clock time changes only as you go east or west. All points on a north and south line have the same time as the zone in which it is located.

For convenience in adjusting the time in America the country was divided into four east and west zones. The first zone takes in everything on a straight north and south line east of Pittsburg, and is called Eastern time. The second zone extends from Pittsburg to Chicago, and is called Central time; the third zone extends from Chicago to Denver, and is called Mountain time; while the fourth zone extends from Denver to the Pacific Ocean. These selections were made because the sun actually rises about one hour later in Pittsburg than in New York; one hour later in Chicago than in Pittsburg; one hour later in Denver than in Chicago, and one hour later on the Pacific Coast than in Denver. Under this plan when it is nine o’clock in New York it is only eight o’clock at Pittsburg and all points in the Central zone; seven o’clock in all points in the Mountain zone; six o’clock in Denver and five o’clock in San Francisco. As you keep travelling westward you drop one hour of the clock time in every zone, and as under this system the earth’s east to west distance is divided into twenty-four such zones, if you went west entirely around the world you would lose a whole day of clock time.

If, however, you went around the world from west to east in the same manner you would gain a whole day.

Where Does the Day Change?

This system of agreeing on fixed places where the hour changes made it necessary to also fix a point where for the purposes of the calendar the day also changes. This imaginary north and south line is fixed upon at 180 degrees west longitude, which would cut the Pacific Ocean in two. This line makes it possible for a person to travel all day before approaching this line and then find himself after crossing it travelling all the next day with the same name for the day of the week. Thus he could spend all of Sunday travelling toward the International Day Line, as this is called, and after crossing it spend another Sunday, which would be the next day, going away from it. This would give him the novel experience of having two Sundays on successive days. The same thing would happen if he were travelling to the Day Line on Monday, Tuesday, Wednesday, Thursday, Friday or Saturday. He would live through two succeeding days of the same name in the same week, one right after the other. This would be in going westward.

If you were traveling eastward and crossed the International Day Line on Sunday at midnight you would lose a day completely out of the week, for when you woke up the next morning it would be Tuesday.

Why Do We Cook the Things We Eat?

We have several reasons for doing this. The first and most important reason to us is that the application of heat to food makes it more easy to digest. Other reasons are that when cooked our food is more palatable; the process of cooking kills all microbes, which, if taken into our bodies alive, would give us diseases, and also it is easier for us to chew food that has been cooked.