In 1920's "Float Bowls" became the rage for floating multiple flower heads and were very intricate with intricate glass figurines of fish/girls riding turtles/dolphins/etc. Later in the 1940's to 50's they became popular again but were less intricate and became better known as a floating bud vase.
You see them used often for display on sideboards/buffets/coffee tables. Have seen them re-purposed in later years to serve nuts/hard candies/jordan almonds, bottom filled with ice and shrimp or shelled seafood presented on the ice, etc.
