The Invention of the Clock
The mechanical clock, was a medieval invention. The ancient world had measured time, none too accurately, by the sundial and the water-clock. Both these were devices known to the Babylonians in the second millennium B.C., and both were improved by the Greeks.
When and where the first machine clock was made is still a matter for investigation and disagreement. A conservative date is the early fourteenth century, and the place was probably northern Italy or southern Germany. Much was certainly involved in the development of the clock - the cloudy north (sundials had been well enough for the cloudless weather of Mesopotamia, Egypt, Greece and the Mediterranean), the daily time-table of monks, and what one might call man's invasion of the night as he found for himself better illuminants.
Many of the adjuncts of the modern wrist watch (strapped there as the one place where the watch is at once easily and quickly read and also conveniently out of the way) are simply old ideas perfected and brought down to wrist-watch size. These include the automatic or selfwinding mechanism, the calendar and the alarm.
By 1350 clocks had reached some degree of perfection in the primitive stage of the craft. Most, if not all, of the early clocks were large; and were set up in church towers, where they guided monks in the performance of their office. They were made of iron, by members of blacksmith's guilds; and were driven by the suspension of weights, mainsprings not being introduced till late in the fifteenth century. Smaller clocks may have existed in the early period, but none has been discovered. It has been argued that the earliest clocks may have been constructed in wood, and so failed to survive.
A mechanical clock, by definition, is not merely a series of tooth-wheels: it must - and this is the distinction - have a controlling device, an 'escapement', which regulates the speed of the wheels and so the speed with which the hands traverse the dial. For more than 400 years the primitive 'verge escapement' performed this duty; though the improved anchor form, introduced in England in 1671, became general soon after in long case or 'grandfather' clocks.
The controlling escapement must itself be controlled, which was effected till 1657 by the foliot, the weighted cross-bar of the early turret clocks. As an alternative to the cross-bar a balance wheel was used in the smaller domestic clocks. In 1657 Christiaan Huygens, the Dutch physicist and mathematician, made both forms obsolete by introducing the pendulum to control the escapement speed. Huygens's pendulum and William Clement's anchor escapement of 1671, between them, made accurate timekeeping possible at last. The pendulum has a natural and regular motion under the attraction of gravity, and since the time of vibration of a pendulum varies as the square root of its length, regulation is easily effected by increasing the length or decreasing it.
Other improvements and inventions were to follow, but the principles of timekeeping had now been settled. A step had been taken towards our organized world of mensuration.
Up to the introduction of the pendulum, domestic or chamber clocks were cased in metal -at first iron, then engraved and gilded brass. Since the earliest chamber clocks were driven by weight, they had to hang on the wall. After the medieval development of the mainspring, clocks could be smaller and made to stand on the table, as shown in Holbein's picture of the merchant Georg Gisze. Elaborate casing now began; and a great many such table clocks were made by German craftsmen in Augsburg and Nuremberg during the seventeenth century.
One may say broadly that from the sixteenth century each country developed its own national styles. Thus England's distinctive wall clock was the type now known as the lantern clock, cased in brass with a silvered chapter or hour ring, and surmounted by a large bell. These lantern clocks enjoyed a long vogue of more than a hundred years from about 1610. The Fromanteels, a Dutch family of clockmakers, brought the pendulum over to England about 1660, three years after it had been introduced by Huygens. The grandfather clock was now developed, the cabinet-maker joining his craft to that of the clock-maker. Fine wooden cases were also made for the mantel or table clock, and design reached its perfection in England between 1675 and 1720.
The craftsmanship devoted to the movement, the hands and the dials by the clockmaker and to the case by his cabinet-maker were exquisite, particularly in the early years.
A watch, in all its essentials, is a clock made small and portable; and it descends from the table clocks which followed when the mainspring was introduced as an alternative to the suspended weight. By 1510, or thereabouts, Peter Henlein of Nuremberg was making clocks so small that they could be 'carried on the bosom or in the purse'. The small portable clocks of this period were contained in a drum-shaped case about two inches in diameter. The first watches may have been similar, with a ring attached to the case to take a neck-cord or chain. Such watches were certainly made around 1575, but records of Henlein's time prove that another type-the spherical or musk-ball watch - was specially associated with him.
The musk-ball or musk-apple, or pomander, was a pierced ball filled with herbs and scent against infection or against stench, and was attached to the lady's girdle. Made in imitation of the musk-ball, Henlein's watches were pierced to emit the sound of the bell, since they struck the hour.
Watches were unmistakably worn as ornaments by 1600, in cases of brass, gilded and chased and bejewelled with pearls and garnished with coloured enamels. Between 1600 and 1650 the shapes became fanciful - stars, crosses, skulls, buds, etc. If the cases were usually of silver or of gilt brass, often now they were cut from rock crystal, agate, or some other ornamental stone.
After the middle of the seventeenth century watch-cases were usually circular and rather thick, and they were rounded at the circumference - in which we see the forerunner of the pocket watch; the watch, in fact, was housed in the breeches pocket until the evolution of man's dress produced the waistcoat.
Watches so far had been poor timekeepers: Huygens once more came to the rescue; and in 1675 made known his use of the hairspring, a spiral spring coupled to the arbor (i.e. axis) of the balance wheel, as controller of the escapement. This was as important to the watch as the pendulum had been to the clock: it made for more precision and placed watchmaking on a scientific basis. Watches could now be provided with a minute hand. Previously an hour hand had sufficed, and the dial had been calibrated only into hours and quarters.
If the balance spring opened the way to exact timekeeping, it also set watchmakers a great many technical problems. First an improved escapement had to be evolved to take full advantage of the timekeeping properties of the balance spring. Ultimately Thomas Mudge devised the lever escapement in 1759, which in principle is the escapement used today. Improvement was driven forward by one matter of urgency: mariners needed an accurate timekeeper 'to find the longitude'; and that meant counteracting the effects which heat and cold have on the balance spring. The solution came before the end of the eighteenth century, and was the cumulative work of several men; balance wheels were contrived of two metals with different expansions. Ordinary watches benefited from this work of perfecting the marine chronometer, and by 1800 a good watch might be expected to keep time to within one minute in twenty-four hours. From the early nineteenth century the watch has remained fundamentally the same machine, improved in many details, particularly in being all of a piece, without the need of a key for winding and hand-setting.