War Department Lightbulb

Update: My thanks to Adrian Fett who has pointed out that the bulb is the wrong shape for a car headlight of this period , which were spherical, as well as having too high a voltage for a vehicle. He suggests it is more likely from something such as a projector.

 It never ceases to amaze me the wide variety of items that were issued with military markings to show they had been procured for army service. Tonight we have an electric lightbulb that may have come from a film projector:imageAs one would expect from this blog, the bulb has the /|\ stamp indicating military issue and a stores code marked on the metal base of the bulb:imageThis is accompanied by a crown and a ‘government property’ stamp:imageThe bulb was manufactured by Osram and their details are printed on the glass in gold:imageOsram were founded in 1905 as an Anglo-German company producing lightbulbs and later radio valves. The First World War saw a restructure and the company became entirely English as Osram GEC and they remained one of the biggest lightbulb companies in the United Kingdom until the Second World War, winning large contracts from the government for bulbs such as this one.

The bulb has a brass ring around the bottom and a black insulated section in the centre:imageOne curious story about a lightbulb in World War Two comes from Bernard Buckle who was a child in Liverpool:

I was twelve, I think, which would make it 1940, when it happened. In our living room we had a large 100 watt bulb of the clear glass type with a filament consisting of a number of wires attached to a central glass core. One night, precisely at ten o’clock, it started to emit a buzzing sound which, after listening closely, my father identified as Morse Code. Being close to both Liverpool and Ringway airports, he reasoned that maybe there were aircraft flying near and, by some fluke, our light bulb was acting as a receiver for their signals. After four nights of the same thing happening at precisely ten o’clock, he decided that it was too much of a coincidence that aircraft should be flying over at the same time every night. In addition, he thought that maybe we were hearing something that wasn’t meant to be heard by us. I was in the Runcorn Sea Cadets at the time and one of the subjects we were learning was Morse Code, but this was much too fast for me to take in.

When my father reported these happenings to the police they sent a sergeant and a constable, who listened gravely and then said it was something for a higher authority. The next night, Superintendent Jackson himself, and his next in command, came for a listen. After about a half hour, the transmissions ceased. My father was told that he wasn’t to say anything about these occurrences. Three nights later the Superintendent arrived, at a quarter to ten, accompanied by two men in plain clothes whom he introduced as “experts from the Isle of Man.” (At the same time there was a training school for wireless telegraphists at H.M.S. St. George, I.o.M.)

After listening to our light bulb buzzing away for three nights, one of these experts suddenly jumped up and rapped it with the back of his fingers, but it kept on remorselessly (no pun intended) tapping out its message. He tried again, giving it a good bang this time, but it kept on going. So, taking a handkerchief from his pocket, he removed the bulb and promised my father that he would get a replacement.

The sequel is, we heard some months later that a spy had been caught living quite close to us, a mere couple of roads away. Whether it was thanks to what the authorities heard through our light bulb or not we were never told. What’s more we didn’t get our replacement bulb either.

Sadly the filament in this bulb has broken so it will never light up again, however for something as fragile as this bulb to have lasted so long is remarkable and it is another odd and obscure piece to add to the collection.


  1. As your lamp is for a 115 volt system it is highly unlikely to be automotive. Pre halogen headlamp bulbs were nearly always short and spherical in order to concentrate the light source within the centre of a bowl shaped reflector so it’s unlikely to be from a headlight. The cap on yours is similar to that used in old projector lamps.

    • I second the projector theory on the basis of the base and also the 115V as many projectors of the time used this voltage supply for some reason.

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