Abstract: A glass pane has a broken pattern of dots of an opaque non-reflective material applied to one side thereof. The pattern is applied as a ceramic ink fused into the glass surface in the heat toughening step. The arrangement of dots is such that the pattern occupies 10% to 30% of the pane surface and comprises 30 to 50 dots per linear inch. A squash or like court formed from a number of such glass panes is such that players within the court are not distracted by spectators outside and can follow the path of a squash ball with ease, whereas spectators outside the court, by virtue of differential lighting as between court and spectator area, can watch the activity within the court without diminished vision.

Abstract: A device for testing lung function has a body with two chambers axially separated by a partition. An impeller is rotatably mounted in a first one of the chambers on a shaft extending through the partition into both chambers. An air inlet leads into the first chamber so that air can be blown into the chamber tangentially on to the impeller thereby to rotate the impeller. A reduction gear arranged in the second chamber and is driven by the shaft. An indicator is driven by the reduction gear to indicate the number of revolutions of the impeller.