Like what I make? Want fewer sponsorship ad reads? Consider contributing to my Patreon at https://patreon.com/OurOwnDevices Bubble lights, patented by Carl Otis in 1944, were a popular christmas tree ornament from the 1940s to the 1970s. The working fluid in modern reproductions is Methylene Chloride, a versatile industrial solvent with a variety of applications - including a certain beloved desk toy.