Bubble light

A bubble light is a decorative device consisting of a liquid-filled vial that is heated and lighted by an incandescent light bulb. Because of the liquid's low boiling point, the modest heat generated by the lamp causes the liquid to boil and bubble up from the vial's base thus creating the bubble light. The liquid is almost always methylene chloride, but some early bubble lights used a lightweight oil. The light from the lamp illuminates the bubbles from underneath, causing them to shine. Bubble lights were very popular as Christmas lights from the 1940s through the 1970s, before miniature "fairy" lights became popular.

Bubble lights were being manufactured by The Telsen Electric Co.(1935) Ltd, in Manchester, England, possibly as early as the late 1920s. Bubble lights for Christmas decoration were first patented in the United States by Carl W. Otis in 1944 and introduced there in 1946 by NOMA, one of the largest American manufacturers of Christmas lights. While NOMA was the largest company to make these lights, other manufacturers included Raylite (Paramount/Sterling), Royal Electric Company, and Good Lite/Peerless.