The history of the pocket watch reflects that of both fashion and horology.
The pendant watches of the early Renaissance were oval or egg-shaped.
Technical collectors may seek minute repeaters (watches that chime the hours, quarter hours and minutes on command), chronographs (stopwatches), chronometers (precision timekeepers invented to determine longitude at sea) or ultracomplicated watches (which combine such extras as a celestial chart, perpetual calendar, alarm, chimes and sunrise and sunset indication).
By the early 1800s, men began securing the watches to gold chains, which were fastened to vests by inserting a T-bar with the watch's winding key into a buttonhole.
Visible in the portraits painted at the time, the chains were male charm bracelets, dangling gold signet seals, keys, scissor blades and pencil cases.
"A lot of collectors are gear geeks," says Vivian Swift, watch-department head at Christie's in New York.
Pocket-watch collectors, however, tend to fall into two general groups: the technical--interested primarily in how they work, and the decorative--concerned more with how they look.
"It is a marriage of art and technology," remarks Osvaldo Patrizzi, director of Antiquorum, the Geneva-based auction house specializing in watches and clocks.
Even the nonmaterialistic seem lured to these timekeepers in a pocket; Mohandas Gandhi's one possession was a pocket watch, which he wore tied on a string around his waist.
The wristwatch is a utilitarian object, designed to inform its wearer of the precise time at a glance.
It is an outward sign, visible to the rest of the world.
She wore it on one wrist and a calendar on the other, pioneering the bracelet watch for women.
By the First World War, the seconds that might elapse while a soldier removed a watch from his pocket to read the time could mean the difference between life and death.
The electronic-alarm system did not work, and the two guards on duty slept as the thieves used a rather primitive device to pry open the cylinder locks on the glass cases that held a large collection of eighteenth- and nineteenth-century pocket watches.