I first came across the Girard-Perregaux watch brand at a school jumble-sale, where I bought a pretty little gold G-P manual-wind watch for £1.00! I came across this ‘Sea Scout’ on eBay and have to say that it’s the only eBay watch buy that I’m really pleased with. It has a ‘bumper’ movement. Bumper watch movements were early types of automatic (self-winding) movements from the 1930s–1950s that used a limited-swing rotor rather than a 360-degree spinning one (which is obviously more efficient, but less simple). The rotor ‘bumps’ at each end of its swing, when it contacts a spring buffer. Interestingly, G-P also created the first watch with a 360-degree rotating automatic movement, called the “Gyromatic” in the 1950s. It used “Gyrotron” wheels to enable efficient bidirectional winding.
But back to this watch – it’s story isn’t finished yet. I bought it from a seller in the US. The movement is accessed through the front of the watch – the winder pulls off to enable this, and the crystal is held on with a tight-fitting ring. The dial is one of the infamous Radium dials and so is radioactive. Radium 226 has a half-life of around 1,600 years. It emits alpha particles and low-energy gamma rays and will be dangerous for a very long time! I understand that the luminosity results from these alpha particles hitting Zinc Sulphide (ZnS) in the luminous paint. The radiation damages the phosphorescent paint though, so this dial is no longer luminous.
The picture here really doesn’t do this watch justice; the picture is (depending on your device) much larger than life-size (the watch is only about 32mm in diameter); also, the crystal is cracked in several places. What you can’t see though, is the back of the watch, which has some pitting corrosion.
