and provide illumination in addition as seen in fig1 the flat or front face of the housing may extend to a region 181 at the top edge of the housing 163 at an angle to the front face therefore particularly in the regions to which the curved light guide sheet 166 does not extend light rays may exit directly through the clear area 181 of the housing 161 for further regulation of the distribution of the light emitted from this arrangement the housing 161 may have a flattened corner shown at 177 which forms a surface for mounting the housing under a shelf or light shield the clear region 181 thus illuminate generally forwardly while the front face 162 would illuminate generally at a downward angle and provides a diffused light source essentially without glare this is particularly useful for illuminating instrument panels of an aircraft beneath a glare shield under which the arrangement may be mounted it will be understood that sheet 164 and areas 178 may be suitably colored if desired it will be understood that where color change is not needed in any of the foregoing forms of the invention a stationary single color outer tube may be used in place of the rotatable outer tube or the outer tube may be dispensed with entirety in the latter case the diffusing strip 12 may be appropriately colored when desired to provide a non white illumination such as for photographic dark rooms or night illumination of instrument panels where desired an extended length source of infra red or ultra violet light may be provided by the present arrangement by placing an appropriate infra red or ultra violet filter between light source 4 or 65 and the.