Abstract: A space defined between two face-to-face panes of a window is adapted to be selectively flooded with a colored liquid in order to reduce the transmission of heat and/or light through the window. The window is characterized by the provision of a supply manifold located between the panes and by the manner of delivering liquid to the manifold and into the space to insure against unequal pressures and thereby eliminate the danger of the panes being broken.

Abstract: An internal combustion engine which is adapted to operate on liquid petroleum gas and including a manually adjustable valve for admitting gas into the combustion chamber to cause the engine to run at a selected speed. A speed responsive governor vane automatically controls the position of a butterfly valve for regulating the flow of combustion air to the chamber and further controls the position of an auxiliary valve for admitting additional gas to the chamber when the engine is under heavy load.