Pocket watch

Antique verge fusée pocketwatch movement, from the 1700s

A French pocketwatch from the 1920s

A pocket watch, retrieved from shipwreck of Titanic from unknown victim of sinking

The first timepieces to be worn, made in 16th-century Europe, were transitional in size between clocks and watches.[3] These 'clock-watches' were fastened to clothing or worn on a chain around the neck. They were heavy drum shaped brass cylinders several inches in diameter, engraved and ornamented. They had only an hour hand. The face was not covered with glass, but usually had a hinged brass cover, often decoratively pierced with grillwork so the time could be read without opening. The movement was made of iron or steel and held together with tapered pins and wedges, until screws began to be used after 1550. Many of the movements included striking or alarm mechanisms. The shape later evolved into a rounded form; these were later called Nuremberg eggs.[3] Still later in the century there was a trend for unusually shaped watches, and clock-watches shaped like books, animals, fruit, stars, flowers, insects, crosses, and even skulls (Death's head watches) were made.

Styles changed in the 17th century and men began to wear watches in pockets instead of as pendants (the woman's watch remained a pendant into the 20th century).[4][5] This is said to have occurred in 1675 when Charles II of England introduced waistcoats.[6] To fit in pockets, their shape evolved into the typical pocket watch shape, rounded and flattened with no sharp edges. Glass was used to cover the face beginning around 1610. Watch fobs began to be used, the name originating from the German word fuppe, a small pocket.[5] The watch was wound and also set by opening the back and fitting a key to a square arbor, and turning it.

High resolution image of a clockwork with silver hallmark and precision surface finish

Wooden pocket watch XIX-XX. Russian stamp, 2010

Until the second half of the 18th century, watches were luxury items; as an indication of how highly they were valued, English newspapers of the 18th century often include advertisements offering rewards of between one and five guineas merely for information that might lead to the recovery of stolen watches. By the end of the 18th century, however, watches (while still largely hand-made) were becoming more common; special cheap watches were made for sale to sailors, with crude but colorful paintings of maritime scenes on the dials.

Up to the 1720s, almost all watch movements were based on the verge escapement, which had been developed for large public clocks in the 14th century. This type of escapement involved a high degree of friction and did not include any kind of jewelling to protect the contacting surfaces from wear. As a result, a verge watch could rarely achieve any high standard of accuracy. (Surviving examples mostly run very fast, often gaining an hour a day or more.) The first widely used improvement was the cylinder escapement, developed by the Abbé de Hautefeuille early in the 18th century and applied by the English maker George Graham. Then, towards the end of the 18th century, the lever escapement (invented by Thomas Mudge in 1755) was put into limited production by a handful of makers including Josiah Emery (a Swiss based in London) and Abraham-Louis Breguet. With this, a domestic watch could keep time to within a minute a day. Lever watches became common after about 1820, and this type is still used in most mechanical watches.

In 1857 the American Watch Company in Waltham, Massachusetts introduced the Waltham Model 57, the first to use interchangeable parts. This cut the cost of manufacture and repair. Most Model 57 pocket watches were in a coin silver ("one nine fine"), a 90% pure silver alloy commonly used in dollar coinage, slightly less pure than the British (92.5%) sterling silver, both of which avoided the higher purity of other types of silver to make circulating coins and other utilitarian silver objects last longer with heavy use.

A so-called "mystery watch" with a transparent dial, c. 1889, Musée d'Horlogerie of Le Locle, Switzerland. It is the first transparent watch.[7]

Watch manufacture was becoming streamlined; the Japy family of Schaffhausen, Switzerland, led the way in this, and soon afterwards the newborn American watch industry developed much new machinery, so that by 1865 the American Watch Company (afterwards known as Waltham) could turn out more than 50,000 reliable watches each year. This development drove the Swiss out of their dominating position at the cheaper end of the market, compelling them to raise the quality of their products and establish themselves as the leaders in precision and accuracy instead.

The rise of railroading during the last half of the 19th century led to the widespread use of pocket watches. A famous train wreck on the Lake Shore and Michigan Southern Railway in Kipton, Ohio on April 19, 1891, occurred because one of the engineers' watches had stopped for four minutes. The railroad officials commissioned Webb C. Ball as their Chief Time Inspector, in order to establish precision standards and a reliable timepiece inspection system for Railroad chronometers. This led to the adoption in 1893 of stringent standards for pocket watches used in railroading. These railroad-grade pocket watches, as they became colloquially known, had to meet the General Railroad Timepiece Standards adopted in 1893 by almost all railroads. These standards read, in part:

...open faced, size 16 or 18, have a minimum of 17 jewels, adjusted to at least five positions, keep time accurately to within 30 seconds a week, adjusted to temps of 34 °F (1 °C) to 100 °F (38 °C), have a double roller, steel escape wheel, lever set, regulator, winding stem at 12 o'clock, and have bold black Arabic numerals on a white dial, with black hands.

There are two main styles of pocket watch, the hunter-case pocket watch and the open-face pocket watch.

Open-face watches

An open-face pocket watch made by the Swiss watchmaker Omega, c. 1970

An open-faced, or Lépine,[8] watch, is one in which the case lacks a metal cover to protect the crystal. It is typical for an open-faced watch to have the pendant located at 12:00 and the sub-second dial located at 6:00. Occasionally, a watch movement intended for a hunting case (with the winding stem at 3:00 and sub second dial at 6:00) will have an open-faced case. Such watch is known as a "sidewinder." Alternatively, such a watch movement may be fitted with a so-called conversion dial, which relocates the winding stem to 12:00 and the sub-second dial to 3:00. After 1908, watches approved for railroad service were required to be cased in open-faced cases with the winding stem at 12:00.

Waltham model 1899 pocket watch movement

Movement of a gold Elgin pocket watch, c. 1919

Pocket watch movements are occasionally engraved with the word "Adjusted", or "Adjusted to n positions". This means that the watch has been tuned to keep time under various positions and conditions. There are eight possible adjustments:

• Dial up
• Dial down
• Pendant up
• Pendant down
• Pendant left
• Pendant right
• Temperature (from 34 to 100 degrees Fahrenheit (1 to 38 °C))
• Isochronism (the ability of the watch to keep time, regardless of the mainspring's level of tension)

Positional adjustments are attained by careful poising (ensuring even weight distribution) of the balance-hairspring system as well as careful control of the shape and polish on the balance pivots. All of this achieves an equalization of the effect of gravity on the watch in various positions. Positional adjustments are achieved through careful adjustment of each of these factors, provided by repeated trials on a timing machine. Thus, adjusting a watch to position requires many hours of labor, increasing the cost of the watch. Medium grade watches were commonly adjusted to 3 positions (dial up, dial down, pendant up) while high grade watches were commonly adjusted to 5 positions (dial up, dial down, stem up, stem left, stem right) or even all 6 positions. Railroad watches were required, after 1908, to be adjusted to 5 positions. 3 positions were the general requirement before that time.

Early watches used a solid steel balance. As temperature increased, the solid balance expanded in size, changing the moment of inertia and changing the timing of the watch. In addition, the hairspring would lengthen, decreasing its spring constant. This problem was initially solved through the use of the compensation balance. The compensation balance consisted of a ring of steel sandwiched to a ring of brass. These rings were then split in two places. The balance would, at least theoretically, actually decrease in size with heating to compensate for the lengthening of the hairspring. Through careful adjustment of the placement of the balance screws (brass or gold screws placed in the rim of the balance), a watch could be adjusted to keep time the same at both hot (100 °F (38 °C)) and cold (32 °F (0 °C)) temperatures. Unfortunately, a watch so adjusted would run slow at temperatures between these two. The problem was completely solved through the use of special alloys for the balance and hairspring which were essentially immune to thermal expansion. Such an alloy is used in Hamilton's 992E and 992B.

Isochronism was occasionally improved through the use of a stopworks, a system designed to only allow the mainspring to operate within its center (most consistent) range. The most common method of achieving isochronism is through the use of the Breguet overcoil, which places part of the outermost turn of the hairspring in a different plane from the rest of the spring. This allows the hairspring to "breathe" more evenly and symmetrically. Two types of overcoils are found - the gradual overcoil and the Z-Bend. The gradual overcoil is obtained by imposing two gradual twists to the hairspring, forming the rise to the second plane over half the circumference; and the Z-bend does this by imposing two kinks of complementary 45 degree angles, accomplishing a rise to the second plane in about three spring section heights. The second method is done for esthetic reasons and is much more difficult to perform. Due to the difficulty with forming an overcoil, modern watches often use a slightly less effective "dogleg", which uses a series of sharp bends (in plane) to place part of the outermost coil out of the way of the rest of the spring.

An 'Hebdomas' 8 day pocket watch, circa 1920, Musée d'Horlogerie of Le Locle, Switzerland. Patented in 1889, discontinued a number of years and reintroduced in 1968 is still manufactured.[12] An example of the decline and resurgence of the pocket watch.

Colibri pocket watch, manufactured mid-1990s. The back case has an extra hinged cover that can be folded out to allow the watch to stand upright on a table.

Pocket watches are uncommon in the present day, having first been superseded by wristwatches and later by smartphones. Until early in the 20th century, though, the pocket watch remained predominant for men, with the wristwatch considered feminine and unmanly. In men's fashions, pocket watches began to be superseded by wristwatches around the time of World War I, when officers in the field began to appreciate that a watch worn on the wrist was more easily accessed than one kept in a pocket.[13] A watch of transitional design, combining features of pocket watches and modern wristwatches, was called a "trench watch" or "wristlet". The more accurate pocket watches continued to be widely used in railroading even as their popularity declined elsewhere.

The widespread use of pocket watches in a professional environment finally came to an end in approximately 1943. The Royal Navy of the British military distributed to their sailors Waltham pocket watches, which were nine-jewel movements, with black dials, and numbers coated with radium for visibility in the dark, in anticipation of the eventual D-Day invasion.

For a few years in the late 1970s and 1980s three-piece suits for men returned to fashion, and this led to small resurgence in pocket watches, as some men actually used the vest pocket for its original purpose. Since then, some watch companies continue to make pocket watches. As vests have long since fallen out of fashion (in the US) as part of formal business wear, the only available location for carrying a watch is in a trouser pocket. The more recent advent of mobile phones and other gadgets that are worn on the waist has diminished the appeal of carrying an additional item in the same location, especially as such pocketable gadgets usually have timekeeping functionality themselves.

In some countries, a gift of a gold-cased pocket watch is traditionally awarded to an employee upon their retirement.[14]

The pocketwatch has regained popularity with the steampunk subcultural movement embracing the arts and fashions of the Victorian era, during which pocketwatches were nearly ubiquitous.[15]

• The Vacheron Constantin Reference 57260 (2015) — 57 complications
• Patek Philippe Calibre 89 (1989) — 33 complications
• Patek Philippe Henry Graves Supercomplication (1933) — 24 complications

• Doctor Who features pocket watches used by The Doctor during their first, third, fourth, sixth, seventh, eighth, war, and eleventh incarnations. The Tenth Doctor and The Master in their war incarnation used pocket watches with technology to pose as humans when in hiding.
• The White Rabbit from Alice in Wonderland was shown to own a pocket watch.
• The human form of Cogsworth in the Disney version of Beauty and the Beast was portrayed with a pocket watch.
• The titular character in the children's TV show Bernard's Watch was shown to own a magical pocket watch that could stop time when the top button was clicked.

• Movado Ermeto watch
• List of watch manufacturers
• List of most expensive watches sold at auction
• Chatelaine (chain)

• Milham, Willis I (1945), Time and Timekeepers, New York: MacMillan, ISBN 0-7808-0008-7.

Look up pocket watch in Wiktionary, the free dictionary.

Wikimedia Commons has media related to pocket watch.

• "Perfect Timepiece", Popular Mechanics, December 1931. Illustration of workings of common mechanical pocket watch.