As we all know the pocket watches and their gears are main symbols of the steampunk culture, that’s why I thought of talking a little about them.
Although there might be some evidence of the use of the pocket watch in the 15th century , they became more popular in the 16th century, being the first timepieces that the public could own. By this time watches didn’t need to stay on the walls but could be carried around the neck or on a pocket .
This engraving depicts a Nüremberg egg, a pocket watch designed by Peter Henlein in the early 16th century. Small, portable clocks like the Nüremberg egg became possible with the development of coiled springs as a power source for timekeeping devices. 
The pocket watch continued to be improved and by the 18th century the developments with the inner spring-workings allowed for a minute-hand to be introduced and the number of wheels within the watch mechanism was increased, thus decreasing the number of times the watch had to be wound up each day (previously it had to be wound twice). 
In the 19th century came the glory days of the packet watches. By the time the Industrial Revolution was in full swing in the nineteenth century and the railroads were criss-crossing all over the United States, United Kingdom and Europe, pocket-watches had become an important part of middle and lower class society as well. Railroad workers in particular relied on the watches for time-keeping, an important element of their job which when done properly could ensure that no accidents occurred.  
My great-great grandfather João Borrega. Since the pocket watches became an important accessory for middle and lower classes too, it is very common to see these timepieces (or their chains) in the 19th century photos.
With the introduction of the wrist-watch in the years leading up to World War I, and then the development of the quartz mechanism, pocket-watches were relegated to the back-seat in the watch world . But they never ceased to exist, still being worn by aficionados (like steampunks) and very appreciated by collectors.