In 1895, the Edison Electric Company offered the first popular miniature base lamps suitable for Christmas tree decorating.
Most collectors refer to the shape of these straight sided exhaust tipped lamps as Edison pears, and also "balloons", "teardrops" or just simply "pears".
The collector can find these lamps that were made in the United States, as well as German and Japanese examples.
After about 1907, miniature Christmas lamps started being made with a black glass insulator at the tip of the base, and the vast majority were originating from Japan.
137 stands for the manufacturer code, 77 is the year und 18 is the week.Dating a Mistress - wow what a header;-) As with most elderly ladies determing the exact age is not easy. The only sure hint except for the PCB number is pot dating. (Pots are the three round thingies with a diameter of 24 mm that keep the pcb in place and whereto the knobs are attached.) Luckily these pots are marked with an EIA code containing the production week. At least now we know that the Mistress can not be older than the pot.The lamps were now round, and were technically referred to as a G-8 or G-9.The "G" stood for a globular shape, and the "8" or "9" stood for the size: 8/8th or 9/8th of an inch in diameter.