The trench watch evolved during World War I, when the traditional pocket watch was found to be impractical during trench warfare. The first trench watches appeared during the Boer War in the late 19th century. Before then the wristwatch or wristlet as it was known, was considered feminine. This stemmed from the earlier inaccuracies of wrist-worn timepieces. Early watches were highly susceptible to variations in temperature, dust, water and the positional effects of gravity. A pocket watch that stayed protected in an upright position in a pocket gave the most consistent time. A lady’s wristlet that moved constantly as the user moved their hand was less accurate. For the men of the period, a watch was a tool, for the ladies an ornament.
Towards the end of the 19th century, the mechanism used by most watches improved considerably with respect to timekeeping. The positional effect of gravity was no longer such a problem. Timing, during warfare, became important, particularly when trying to coordinate attacks against well-organised troops such as the Boers. Soldiers began to wear modified pocket watches on their wrists, with lugs soldered on that allowed wrist straps. These were much easier to access than a pocket watch that was stored in a tunic. A soldier could aim their rifle, and turn their wrist to tell the time, rather than dig through their tunic pockets for their watch.
Once World War I started, there were specialist wristwatches designed for battle. It soon became evident that illumination was required for telling the time. It could be fatal if a soldier needed to light a match to tell the time in the dark, as they would become the target of snipers. A luminous dial was developed using radium paint. The hour markers could be marked using the new paint, which allowed soldiers to tell the time in the dark. This was crucial to allow soldiers to coordinate their movements in line with the barrages of artillery. This was particularly crucial to align with the timings on the creeping barrages that required soldiers to move behind an artillery attack that moved forward. A mistimed movement of troops could result in casualties caused by friendly fire.
The luminous paint glowed because of a reaction between the zinc sulphide phosphor in the paint mixture and the gamma rays emitted by the radium. The glow was so luminous it could be noticed in daylight. Initially, the paint was added in small dots on the dial and the hands. As the war progressed the numerals and the hands were completely painted.
The dials would have to be repainted every few years as the phosphor degrades quickly under the constant gamma-ray barrage of the radium. The same cannot be said about the radium, it has a half-life of 1600 years, so it remains very much radioactive. This does create a dilemma for the trench watch collector as their prized possession is constantly emitting potentially dangerous radiation. Even those watches where the paint has been removed will still contain traces of radium beneath the lens. Dropping the watch and shattering the lens could result in fine radioactive particles being drawn into the lungs. Be careful. If you collect trench watches, beware of the radioactive material and never let them near children.
Many early trench watches were modified pocket watches that had wire lugs soldered onto them to allow a wrist strap. Quite often the straps were long enough to allow them to fit over a greatcoat. They also included shrapnel guards, which were supposed to protect the delicate crystal lens. Other trench watches converted from pocket watches included hunter and half-hunter cases.
Prior to the Great War, the pocket watch was considered the only timepiece suitable for men. Wristwatches were called ‘wristlets’ and considered ornamental and feminine. As the soldiers returned from the war wearing their new wristlets, the trend became acceptable. At the war’s end, the surplus of trench watch movements meant that wristlets were being produced into the 1920s with movements dated from the war years. The term ‘wristwatches’ didn’t become mainstream until several years after the war had finished.
If you are collecting trench watches, be mindful of the radioactive paint and also understand that the date of movement doesn’t always reflect that the watch came from the war period. I generally look at the hallmarks on the case, rather than the movement to determine if the watch could be a genuine trench watch.