New mysteries continue to be uncovered at historic Glensheen Mansion, with the latest subject of intrigue an old diving bell that was pulled from the water beneath the old boathouse.
Staff at the Duluth manor have been aware for years there was something in the water beneath the boathouse, and would explain on tours that they believed it was a diving bell.
It was finally confirmed on Thursday, when teams hauled the diving bell out of the water so it could be looked at for the first time above ground since the last time it entered the water.
Glensheen says this was made possible due to storm damage inflicted on the boathouse in October 2017, requiring repair work that presented the opportunity of lifting the bell out of the water.
"We have debated for years whether it was actually a diving bell. We are much more sure today that it is, and it is much larger than expected," Glensheen wrote on Facebook.
"Still a lot questions remain, but now with it out of the rock and water, answers will start to arrive: What exactly is it? Why do they have it? How was it used? Who used it?"
Glensheen director Dan Hartman told the Duluth News Tribune that "legend has it" that the diving bell was used by Alfred Bannister, the nephew of Clara Congdon who lived at Glensheen for most of the 1920s.
He also said that he hopes the bell won't stay at the mansion, but will instead be taken in by another music "with climate control."
A diving bell was used for underwater exploration before the days of submarines and scuba diving.
According to MadeHow, versions of diving bells may have been used as early as the 4th Century, having been observed by Greek philosopher Aristotle, before more robust versions were built in the 17th Century, and then modern versions for commercial purposes were made after World War II.
They work by basic physics, with the open end of the bell being lowered first into the water, and as it does so, the water forces the air up, creating an air pocket in the bell that allows a human to breathe despite being underwater.
You can practice it yourself by simply placing a glass upside down into a tub of water and watch as a pocket of air remains inside.