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From sundial to multi-hand timepiece

 

Why tower clocks with one single hand have become so rare

 

The pictures collected in the course of the readers’ competition demonstrate beautifully a fine tradition that MeisterSinger with its single-hand watches is keen to preserve: the mechanical timepieces on the church and town hall towers of the Middle Ages that made the time of day clearly visible for everybody far and wide, using a single hour hand.

The driving principle of their novel clockwork mechanisms is, without a doubt, one of the most important technological breakthroughs in the history of humanity – although we do not know exactly when or who first had the brilliant idea to divide the passing of time into the small steps of identical size that have served to make time actually measurable. It may have been an Italian monk, or possibly a cleric in Exeter, England, where a mechanical clock is already known to have existed as early as 1284. The rapidly spreading popularity of this new technology during the 14th century was most likely due to its superiority over its predecessors, as the sundials of antiquity only showed the time when the weather allowed, and at night it was simply not measured. Although water clocks were able to measure time without the sun by means of time markers, they were only practical for measuring short periods of time and not necessarily for indicating the time of day. And the hourglasses? They only became a reliable instrument in the 19th century after their physical principles had been understood and their glass bulbs could be manufactured with sufficient precision.

The great innovation in mechanical clock movements was not the wheels and cogs with which the power of a heavy weight was transmitted to drive the rotating movement of the hands. The crucial difference was the principle of the oscillator, a component that alternately blocked and released the movement of the wheels and therefore divided time into precise steps – just as the pallets and balance do in today’s wristwatches. Back in the Middle Ages, this task was performed by the so-called foliot, a heavy wooden beam that oscillated back and forth above the forged iron movement. This method of measuring the time of day may not have been very exact by modern standards, but as the time applied equally to everyone, it enabled people to do things such as get to church on time or arrange appointments, whether business or private.

As the first highly exact clocks were equipped with a minute hand in the late 16th century, it was presumably not only due to the fact that clockmakers had learnt to construct better geartrains from homogeneous metal alloys and to minimize their friction. The increasing organization of early manufacturing caused people to think in increasingly short time periods, such as in quarters of an hour, which were more or less exactly indicated by the additional hand.

It was around the end of the 17th century that an important technical innovation led to many (and one is tempted to say “luckily not all”) tower clocks being fitted with a minute hand: the era of the adjustable pendulum had begun. Initially conceived by Galileo Galilei, it was first built into a clock by Christiaan Huygens in 1656 or 1658 – and reduced the daily inaccuracy of the movements from more than 15 minutes down to a few seconds. Thus equipped, the public clocks became synchronous with the imposing grandfather clocks that kept the time in people’s homes and places of work – as the pacemakers of a new society in which the minutes, and increasingly the seconds, became ever more important.

These developments beg the question more than ever as to why many of the large clocks, such as those seen in the summer competition, still have only one hand, even today. It can hardly be for technical reasons, as very few of them can still be powered by a movement dating from the Middle Ages using a foliot. The more likely – and far more appealing – answer is the assumption that their owners did not see the need for a minute hand and could have even found them disturbing in their perception of time, as they knew what was important for them and definitely did not allow themselves to be hurried by the passing of the minutes.