Abstract: To accomplish the removal of warm fog about an area such as an airport runway (11) shown in FIG. 1, a plurality of nozzles (17) along a line (15) adjacent the area propelled water jets (19) through the fog to heights of approximately twenty-five meters. Each water jet (19) breaks up forming a water drop size distribution that falls through the fog overtaking, colliding, and coalescing with individual fog droplets and thereby removes the fog. A water retrieval system (15) is used to collect the water and return it to reservoirs (21) for pumping it to the nozzles (17) once again.

Abstract: A viewing chamber which permits observation of a sample retained therein includes a pair of double window assemblies mounted in opposed openings in the walls thereof so that a light beam can directly enter and exit from the chamber. A flexible mounting arrangement for the outer windows of the window assemblies enables the windows to be brought into proper alignment. An electrical heating arrangement prevents fogging of the outer windows whereas desiccated air in the volume between the outer and inner windows prevents fogging of the latter.