1000w Projector Lightbulb

Lightbulbs are, by their nature, incredibly fragile; it is therefore always nice to find original World War Two militay examples that have survived the last eighty or so years intact. Some are very small, others however are far more visually impressive, as in the case of this very large example, here depicted with a pound coin for scale:

This bulb, of course, is an incandescent bulb and looking at it carefully it seems the filliment is still intact within the glass:

The bulb has a screw fitting to the base and this is marked up with details of the date and a /|\ ownership mark:

Note also the voltage and wattage marked into the brass. The other side of the base has the manufacturer’s details:

The reason this bulb has survived so well is that it is still packaged in its original stores box which is made of robust cardboard:

Inside this the bulb is packaged in corrugated cardboard and a piece of printed grease proof paper:

Unwrapped and laid out we can see the manufacturer’s trade mark of ‘Royal Ediswan’:

This then leads us to the final and most important question- what was the bulb used for? Unfortunately the store’s label is rather damaged, however from the remaining lettering it seems it was for some sort of projector:

With such a powerful bulb, this was clearly no ordinary slide projector and the best candidate is a special projector called an epidioscope that had the ability to project images from a solid item such as a book onto a screen. In order to do this a series of mirrors or lenses is used in conjunction with very powerful bulbs and it seems likely that this bulb was for use with one of these, perhaps for use in a classroom when instructing troops.

One comment

  1. In 1970 I did a short military course on the interpretation of aerial photographs. During initial classroom instruction photos were projected onto a large screen from an Epidiascope. I never saw the bulb but the machine was a large black japanned metal device about 15 inches tall on a base about 24 inches by 12 inches with a large tubular lens.

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