Abstract: An insulating double glass pane which is intended particularly for glazing roofs such as the roofs of hothouses comprises a first pane and a second pane spaced apart from each other with spacer pieces between them around their edges. The first pane has a portion along one edge projecting beyond the second pane and the distance between the first pane and the second pane decreases from the edge at which the first pane has the projecting portion towards the opposite edge. Preferably the decrease in the distance between the panes from one edge to the other is substantially equal to the thickness of the first pane so that when two of the double panes are laid edge to edge with the projecting portion of an upper pane overlapping the upper edge of a lower pane, the outside faces of the two second panes are substantially flush with each other.

Abstract: A controller for controlling the operation of an automatic machine which includes a number of pneumatically operated devices, for example a machine for blow moulding hollow glass articles, comprises a closed box containing a number of valves each of which is arranged to control one of the pneumatically operated devices of the machine. A first compressed air supply system is connected to the box for supplying compressed air to some only of the valves in the box, the remaining valves being shut-off from this system, and a second compressed air supply system is provided for supplying these remaining valves which are not supplied by the first system. Pressure relief means is also provided for de-pressurising one of the systems so that the valve supplied by this system and the devices which they control become inoperative while the other valves remain pressurised by the other system and accordingly the devices controlled by these other valves remain operative.