Window adapted to be flooded with liquid

A window comprising a pair of upright panes made of transparent material and disposed in spaced face-to-face relation whereby a space is defined between said panes, means extending around said panes and establishing a liquid-tight seal around said space, a liquid supply manifold disposed within said space, said manifold comprising upper and lower tubular branches disposed adjacent the upper and lower margins, respectively, of said panes and further comprising two upright tubular branches disposed adjacent the left and right side margins of said panes and each establishing communication between said upper branch and said lower branch, liquid inlet means opening out of said lower branch and communicating with said space, gas outlet means in the upper end portions of said upright brances and establishing communication between said space and said upright branches, a supply reservoir containing liquid and communicating with said lower branch, an overflow reservoir communicating with said upper branch, means for selectively pressurizing said liquid to deliver said liquid from said supply reservoir to said manifold with said liquid flowing into said space by way of said inlet means and flowing to said upper branch and thence to said overflow reservoir by way of said upright branches, the gas in said space being expelled from said space through said outlet means and said upper branch as liquid enters said space through said inlet means, and means for selectively pressurizing said overflow reservoir and said space to return liquid to said supply reservoir, the liquid from said overflow reservoir flowing into said upper branch and through at least one of said upright branches to said lower branch and then flowing to said supply reservoir, the liquid from said space returning to said lower branch by way of said inlet means and then flowing to said supply reservoir.