I did find that during the period around 1909 was when many changes in the bulbs was taking place. The gas bulbs was being replaced by incentdent type, what is used today, the bulb was taking the shape of modern ones around this period. If a modern bulb today fits then it is a one the the first of it kind around 1909. This is early electricity and rich city folks was in a new luxery at this time. As for Mica, it is a natural material that can easly be carved into the wonderful cylinders that would make wonderful subtle lite, Mica is easly flaked and over time that would be expected. As for the short out situation should have little to do with being made for early electricity, No transformers are required for bulbs, I would say it must have a cord problem. Consider, maybe making them functionable, Not sure how much that would effect value, but may make them easier to sell.