[crackle]

I remember my Dad fitting ordinary round mes bulbs to our sting of lights when the original decorative ones blew, he painted them with red or green paint. Looked a little odd but allowed the others in the chain to work. They were held together with ceramic thimbles that you screwed the wires into to join the cables. Dangerous or what, and Dad was a MIEE.
I remember at the time when I was about 7 or 8 years old, I was confused why, when you fitted a lower voltage bulb it would often be dimmer than expected. ( I know now it is to do with the current)