Here is some information from Jerry Lang. I'm going to share photos here with a link to the message board they are posted on. These are some of the best vintage diver photos I've seen and I'll try and add a few more each day.
http://www.mnscuba.com/forum/showthread ... 5#pid40955
Bob Travsi Keagle
Travis was to my knowledge the first active helmet,rebreather, scuba diver in Minnesota,he started in the late 30's and this is documented.
He wrote an article about making a shallow water helmet from an old hot water heater in 1937.
Also according to his son he used and aviators mask and pure oxygen to a safe depth of 15feet,he also made a rebreather and used it to recover a pair of false teeth in Lake Calhoun circa 1949.
Travis diving was an a underwater and surface photographer and in the early days formed Minnesota Skindivers club,had a dive shop and later moved to Orlando Florida.
Lots of the early scuba was converted aviation regulators and surplus bushed tanks.
Please look at the vintage photos his son was kind enough to provide.
Jerry