Syracuse NY - Although it resembles an ordinary lampshade, this one has been developed with the aid of General Electric engineers for the grim task of determining the position of an atomic bomb blast. A number of these would be mounted out-of-doors around a possible target area, heat radiation would scorch the paint on the inside of the lampshade. Brass rods, shown in center, would block radiation, however, and cause a shadow or image of itself on the scorched region. By means of numbering and lettered grids, the shadow would automatically plot information, from which could be computed the height of the blast and "ground zero" the point directly beneath the blast.

General Electric Company1951-09-05