Thus far we have concentrated on the technical developments that led to improved timekeeping, and we have seen how these developments were utilized in scientific and national standards laboratories, where the utmost accuracy and stability are required. Now we shall turn to the more pedestrian timepieces, which we can carry in our pockets or wear on our wrists. These watches operate in a manner similar to their laboratory cousins, but they are less accurate for reasons of economy, size, and convenience.

THE FIRST WATCHES

The word watch is a derivation from the Anglo-Saxon wacian meaning "to watch," or "to wake." Probably it described the practice of the man keeping the "night watch," who carried a clock through the streets and announced the time, as well as important news or simply called out, "Nine o'clock and all's well."

Early clocks were powered by weights suspended from a rope or chain-an impractical scheme for portable timepieces. The breakthrough came in about 1500, when Robert Henlein, a German locksmith, realized that a clock could be powered by a coiled brass or steel spring. The rest of the clock was essentially the "foliot" mechanism already discussed on page 26, which was very sensitive to whether it was upright in position or lying on its side.

In 1660 the English physicist Robert Hooke toyed with the idea that a straight metal spring could act as a resonator in a clock; and in 1675 the Dutch physicist and astronomer Christian Huygens employed this principle in the form of a metal spiral

ANCHOR ESCAPEMENT

spring connected to a rotating balance wheel; energy flowed back and forth between the moving wheel and the coiled spring.

Hooke is also credited with development of a new kind of escapement, the "anchor" escapement-so called because of its shape which with the help of its "escape wheel" delicately transferred energy to the resonator of the clock. With these developments, the accuracy of clocks improved to the point where the minute hand was added in the latter part of the 1600's.

The history of watches, up until about the middle of the 17th century, was essentially one of gradually improving the basic design of the first watches-most of which were so large that we would probably refer to them today as clocks. As Brearley explains in Time Telling through the Ages: "Back in 1650 it was some job to figure out the number of teeth in a train of wheels and pinions for a watch, to determine their correct diameters, to ascertain the number of beats of the escapement per hour, and then design a balance wheel and hair spring that would produce the requisite number; to determine the length, width, and thickness of a main spring that would furnish enough and not too much power to drive the mechanism; and finally, with the very crude and inadequate tools then available, to execute plans and produce a complete watch that would run and keep time-even approximately."

One significant development occurred in 1704, when Nicholas Facio, of Basel, Switzerland, introduced the jeweled bearing. Up to that time, the axles of the gears rotated in holes punched in brass plates-which considerably limited the life and accuracy of the watch.

Before the middle of the 17th century the production of clocks and watches was largely the work of skilled craftsmen, principally in England, Germany, and France, although it was the Swiss craftsmen who introduced nearly all of the basic improvements in the watch. The watchmaker-or "horological artist," as he was called-individually designed, produced, and assembled all parts of each watch, from the jeweled bearings and pinioned wheels to the face, hands, and case. In some cases an horologist might take an entire year to build a single timepiece.

In Switzerland, however, and later in the United States, watchmakers became interested in ideas that the industrial revolution was bringing to gunsmithing and the making of other mechanisms. The manufacture of identical and interchangeable parts that could be used in making and repairing watches made possible the mass production of both expensive and inexpensive watches. Turning to this kind of standardization, Switzerland rapidly became known throughout the world as the center for fine watchmaking. About 6000 watches were produced in Geneva in 1687, and by the end of the 18th century Geneva craftsmen were producing 50,000 watches a year. By 1828 Swiss watchmakers had begun to make watches with the aid of machinery, and mass production of watches at a price that the average man could afford was assured.

But it was in the United States that the idea of machine-produced interchangeable parts finally resulted in a really inexpensive watch that kept reasonably good time. After many false starts and efforts by various persons that met with little success, R. H. Ingersoll launched the famous "dollar watch" about the end of the 19th century. A tremendous success, it sold in the millions throughout the next quarter century or more. The first were pocket watches, encased in a nickel alloy; but as the wrist watch gained acceptance and popularity in the 1920's, Ingersoll also manufactured both men's and ladies' wrist watches.

MODERN MECHANICAL WATCHES

It was style consciousness that was largely responsible for continued changes and improvements in the watch mechanism. The challenge of producing watches small and light enough to be pinned to the sheer fabrics of ladies' daytime and evening dresses without pulling the dress lines out of shape resulted in the dainty, decorative pendant watches popular in the early 1900's. Designing works that would fit into the slim, curved wrist-watch case that became increasingly popular with men was a major achievement after World War I.

OKING FEATURES SYNDICATE, INC. 1977-REPRINTED BY PERMISSION OF KING FEATURES SYNDICATE Accuracy, stability, and reliability also remained important goals. The multiplying railroad lines, with their crack trains often running only minutes apart by the latter half of the 19th century, helped to create a strong demand for accurate, reliable watches. Every "railroader," from the station manager and dispatcher to the engineer, conductor, and track repair crew with their motorcar, had to know the time, often to the part of a minute. A railroad employee took great pride in his watch-which he had to buy himself and which had to meet specified requirements.

Before electronic watches entered the scene, the Union Pacific Railroad required that all watches have 21 jewels and that they be a certain minimum size. Today electronic wrist watches are allowed, but whatever the type, each morning a railroader's watch must be checked against a time signal coming over a telegraph

wire or the telephone, and it must be within 30 seconds of the correct time. As an additional safety measure, watches are checked on the job by watch inspectors, who appear unannounced. Time, to the railroads, is still a very serious matter.

Today's mechanical watch is a marvel of the art of manufacturing and assembling of tiny parts. The balance wheel in a ladies' wrist watch has a diameter about the same as that of a matchhead, and the escapement ticks over one hundred million times a year, while the rim of the balance wheel travels over 11,200 kilometers miles in its back-and-forth journey. The balance wheel is balanced and its rate adjusted by over a dozen tiny screws around its rim. Some 30,000 of these screws would fit into a ladies' thimble, and the jewels may be as small as specks of pepper. It's no wonder that the tiniest piece of dust can stop a watch or seriously impair its motion.

Even oiling a watch is a delicate operation. One single drop of oil from a hypodermic syringe is enough to lubricate over a thousand jeweled bearings. An amazing variety of substances have been used for lubrication, ranging from porpoise-jaw oil to today's modern synthetic oils.

"Every night, when he winds up his watch, the modern man adjusts a scientific instrument of a precision and delicacy unimaginable to the most cunning artificers of Alexandria in its prime." -Lancelot Hogben

ELECTRIC AND ELECTRONIC WATCHES

A very big step in the development of the watch occurred in 1957, with the introduction of the electric watch. This watch was essentially the same as its mechanical predecessor, except that it was powered by a tiny battery instead of a spring. Two years later, in 1959, a watch was introduced with the balance wheel replaced by a tiny tuning fork. Historically we have seen that the quality factor, or Q, of resonators increases with resonance frequency. The balance wheel in mechanical watches swings back and forth a few times a second, but the tuning fork vibrates several hundred times a second, with a Q around 2,000-20 times better than the average balance wheel resonator. Such watches can keep time to a minute in a month. The tuning fork's vibrations are maintained by the interaction between a battery-driven, transistorized oscillating circuit and two tiny permanent magnets attached to the ends of the tuning fork.

THE QUARTZ CRYSTAL WATCH

The quartz-crystal wrist watch, which is a miniature version of the quartz-crystal clock discussed on page 40, is the latest step in the evolution of watches. Its development was not possible until the invention of the integrated circuit-the equivalent of many hundreds of thousands of transistors and resistors in an area only a centimeter or less on a side. These circuits can carry out the many complex functions of a watch, one of the most important being the electronic counting of the vibrations of the quartzcrystal resonator.

The first quartz wrist watches utilized the "hands" type of display, adapted from existing watches. But later versions became available with no moving parts at all. The hands have been replaced by digital time "readouts" in hours, minutes, and seconds formed from small luminous elements that are entirely controlled by electrical signals. Quartz watches today are accurate to one minute a year, but they are in a very early developmental stage, and it is too early to predict what ultimately may be achieved. HOW MUCH DOES "THE TIME" COST?

Clocks and watches are big business. In 1974, 200 million clocks and watches were sold worldwide for a price of four billion dollars, but the basic value of every one of these timepieces depends on its being "set" to the "correct" time, and then having access to a source against which it can be checked occasionally. So how much does "the time" cost?

For about 99 percent of the people who want to know what time it is or to clock the duration of time-a clock or watch that "keeps time" within a minute or so a day is acceptable. The familiar and inexpensive wall or desk clock driven by the electric current supplied by the power company is completely adequate for the vast majority of people; few persons recognize a need for a more "refined" time. Using only his eyes and fingers, a human being has not the manual dexterity to set a clock or watch to an accuracy of better than a second or so, even if he has the time and patience to do it.

"Losing" the time altogether, when a clock or watch stops, is no problem to most people. One simply dials the telephone company time service or consults another of the many possible suppliers of the "correct" time. In short, for nearly everyone, in nearly all circumstances, the wide choice of clocks and watches available in the local drug or department store at prices of $5.00 and up is sufficient to meet everyday needs.

But let's suppose that a man is going into a remote area on a trip, where he has no radio receiver and will have no contact with