Time is what prevents everything from happening at once. ~John Archibald Wheeler

Continuing developments to the mechanisms that drove clocks did eventually lead to increasing accuracy in time keeping.
The invention of the mainspring lead to the development portable timepieces. The inventor of the mainspring is unknown but references to 'clocks without weights' and two surviving examples show that spring powered clocks appeared in the 15th century Europe. The mainspring is a flat ribbon of steel wound in a coil and attached to the gears of a clock. When the mainspring is wound up and released, it drives the gears as it unwinds.
These clocks and watches gained or lost time in such unpredictable amounts that no one thought of using them to tell the time they were seen more as ornaments. These portable clocks were the first timepieces that the more wealthy people could own they weren't worn on the body.

The First Spring Driven Clocks only had an hour hand. The face was not covered with glass. 
The movement was made of iron or steel and held together with tapered pins and wedges,
 screws weren't used till after 1550.

Some sources credit Peter Henlein (1480-1542), a German locksmith  and watchmaker working in Nuremberg as the inventor of the watch as he was a well known craftsman of early "clock-watches" (taschenuhr), ornamental timepieces worn as pendants which were the first timepieces to be worn on the body.
Improvements to the design of the escapement and the methods used to drive these portable timepieces were continually being made.
Want to buy a replica click here

When Christiaan Huygens made the first attempt at a marine chronometer in 1673 in France, he used a balance wheel and a spiral spring for regulation. A balance spring, or hairspring, is attached to the balance wheel, it controls the speed at which the wheels of the timepiece turn and so the rate of movement of the hands. Huygens spring was an improvement on the straight spring invented by Robert Hooke, unfortunately his clock remained inaccurate at sea.

Drawing of one of his first balance springs, attached to a balance wheel, by Christiaan Huygens.
Published in his letter in the Journal des Sçavants of 25 February 1675.

John Harrison eventually created his accurate marine chronometer H4 based on the design of a large pocket watch (his design was too complicated to be replicated on mass).
Pocket watches continued to evolve, the box-like shaped was replaced by more rounded and slimmer cases.
Thomas Mudge's lever escapement (1754) was a great leap forward and is still used in mechanical watches, in a modified form, today.  

Queen Charlotte's Lever Watch and Pedestal
Probably acquired by George III for Queen Charlotte in 1770
(Backplate signed Tho Mudge / London)

Queen Charlotte's Lever Watch and Pedestal made in 1770, currently part of the Royal Collection, appears to have been the first timepiece to use this important development, the earliest known example of the lever escapement. Also, this was the first pocket watch to have an automatic device for compensating changes in temperature.
Still at this time watches were still being produced in small batches in small workshops and owned by the wealthy.
In the 18th century jewels were used as bearings, diamonds became part of some pocket watches and oil was used to lubricate and smooth the movement of the watch parts.
The 1850's saw the introduction of machine made watches, made in Switzerland and the United States, these were eventually produced at such low prices that by the end of the century ordinary people could afford a watch.
Read this interesting story about President Lincolns Pocket Watch
The beginning of the twentieth century saw the introduction of the wrist watch, still seen as a piece of jewellery just for women, but following its successful use in service during the First World War (1914-18), increasingly among men.
More about the development of wrist watches in a future blog.

"knowing the sky, knowing your relationship with the sky, is the centre of the real answer to knowing what time it is." Tom Wujek

I did say I would write more about the development of clocks and watches. Researching this subject has been very interesting and there is so much information that I have condensed into an outline here.
The ancient Greek, Roman, Chinese and Islamic cultures all developed similar methods to mark the passage of time, oil lamps, candles, sundials, water clocks, merkhet, astrolabe. What was clear that these ancient civilisations had some amazing geniuses (or genii for the correct Latin spelling) that were able to use their knowledge of mathematics and astronomy to develop some wonderful instruments; to tell time, to be used as calendars and to track the movements of the sun, moon and stars, for use in astronomy and astrology. Sadly through the passage of time - and wars - these inventions were lost and we had to start again in the West.
Some (not all) of the greats in Time Keeping (click the name to read more) include:
Ctesibius (born in Alexandria around 300 BC) whose improvements to the water clock resulted in a time-recording device whose accuracy could not be improved on for over 1,500 years.
Hipparchus of Nicaea (born in 190 BC) who accurately recorded  the movement of the sun, moon and stars and other planets and developed trigonometry and constructed trigonometric tables and solved several problems of spherical trigonometry
Andronicus of Cyrrhus (born 100 years BC) whose Horologium (time keeping piece) called the Tower of The Winds still stands today. This public clepsydra (water clock) was driven by a stream flowing down from the Acropolis.

The Tower of the Winds, Athens.

Hypatia (born in Alexandria 370 AD) credited with creating a geared astrolabe and a planesphere.
Since ancient times as a kind of analogue computer know as an astrolabe has been used to find the time during the day or night, find the time of a celestial event such as sunrise or sunset and as a handy reference for teaching astronomy. The celestial sphere, containing  the astronomical objects - moon, sun and stars, is projected on to the plane of the astrolabe (stereographic projection). The moveable componants are lined up to correspond to the users current position and once set, the entire sky, both visible and invisible, is represented on the face of the instrument.

Watch this short animation to see a demonstration.
Download an astrolabe app for your iphone here

The Clock at Hogwarts based on the design of an Astrolabe.

There is no one person responsible for the invention of mechanical clocks rather there were developments and improvements.
Original clocks were astrological clocks based on the design of the astrolabes. The Prague Astronomical Clock or Prague Orloj is a medieval astronomical clock. It was installed in 1410, making it the third-oldest astronomical clock in the world and the oldest one still working.

Prague Orloj

So how did we get from those astrological clocks and water clocks to perpetual movement mechanical clocks, it was the development of a mechanism called an escapement.
1280-1320 saw increasing references to clocks and horologes and existing water clocks being adapted to use falling weights to power them. The release of this power was controlled by the escapement. The earliest record of an escapement being used is in medieval China - Su Song incorporated a kind of escapement in his astronomical Clock Tower of Kai Feng (1088) but it was reliant on water to power it. The date of when an escapement was first used in a clock is unknown.The first clear drawing of an escapement was by Jacopo di Dondi and his son in 1364. It is estimated that escapements were being used in mechanical clocks  in the late 1200's. 

Verge and foliot escapement from De Vick clock, built Paris, 1379, by Henri de Vick

The first mechanical clocks were no more accurate than the best water-clock accuracy. However, overtime the improvements to the design of the escapement, the method of driving the mechanism and the materials used to make them lead to very accurate time pieces. Read in detail more here.
Click here to see the British Museums wonderful animated demonstration on how an escapement works.
Salisbury Cathedral has the worlds oldest mechanical clock, installed 1386, that still strikes the hours.
Next blog how watches developed for portable clocks.
If you are really interested in the subject and curious to see old clocks and watches click here to take a look at the Antiquarian Horological Society Website.

I don't wear a watch. I want my arms to weigh the same.

The words of Harry Hill. Anyone else out there not wear a watch? My husband has a bit of a collection, the most precious both in material and sentimental value is a watch left to him by his grandfather. Harvey Lewis was born in the 1890's, he grew up in the East End of London where he trained and qualified as a Ladies Master Taylor. Just before the WW1 he married and moved to North London.  During the war he was a bit of a wheeler dealer then after he established a flourishing tailoring business which he ran from his front room. The success of this lead to him rewarding himself with a Rolex Zebra Striped 9K Gold Prince Brancard wristwatch.

The Rolex Prince Watch

On October 1, 1927, the patent number 120849 was granted for a movement that was to be named Prince. The main advantage of the movement design was that, by placing the winding barrel and the balance at opposite ends of the watch, they could each be much larger. The Rolex Prince watch proved to be one of the most accurate wristwatches made. The accuracy comes from the very high quality balance wheel, which most unusually for a wristwatch used solid gold screws to add extra weight and therefore, momentum. The watch also had a very high quality finish to the whole escapement, even the wheels. All of these efforts went to ensuring the accuracy of the Prince. Rolex Prince with two dials is often referred to as a ‘doctors watch’ or ‘duo-dial’. The strap is a replacement however it still has the original gold plated pin buckle. The watch was given to Max, Harvey's only child, who hardly wore it and kept it in a safe for many years before passing it on to his younger son. Feel tempted to buy one? click here to make an offer.
Harvey also left some labelled coat hangers and wonderful wool fabrics that have since been made into suits.

Watches have become a fashion accessory and for some a status symbol, others - just need to know the time. Which has made me wonder when man first had the need to tell the time, just going to google that question.......It seems that our forebears invented methods to divide the day or the night into different periods in order to regulate work and for ritual/religious festivals. The lengths of the time periods varied greatly from place to place and from one culture to another. An Egyptian sundial from about 1,500 BC is the earliest evidence of the division of the day into equal parts, but a sundial couldn't be used at night so other methods such as water clocks (clepsydra), oil lamps and candle clocks were developed. Click here to read about sundials in detail and make your own - all very mathematical.
In 27 AD Hipparchus of Niceae, working in Alexandria, proposed dividing the day into 24 equinoctial hours. Equinoctial hours, are based on the equal length of day and night at the equinox, split the day into equal periods. However, ordinary people didn't adopt this for well over a thousand years. (The conversion to equinoctial hours in Europe was made when mechanical, weight driven clocks were developed). The division of time was further refined by another Alexandrian based philosopher, Claudius Ptolemeus, who divided the equinoctial hour into 60 minutes, using by the scale of measurement of ancient Babylon.
The first clock escapement mechanism appears to have been invented in 1275 and subsequently watches evolved from these portable spring-driven clocks. More detail to follow in future blogs.

If you get a chance to visit the The science museum you can see a collection of early watches there.