Our company, Chaney Instrument Co., had the distinction of having the "world's largest tube thermometer" about 40 years ago- it was on display in front of the old WI manufacturing facility in a downtown setting. That tube was huge and initially used mercury- LOT's of mercury. Was later replaced with a alcohol tube and eventually taken down altogether. The tube is still sitting in a crate in our warehouse somewhere, it's gotta be 40 feet long!