This experiment was conducted in the central and southeast coast of hte United States to study primarily the effects of aerial seeding with dry ice and ground seeding with silver iodide on the intensification of large-scale storms, and secondarily the effects of such seeding on rainfall. Storms selected for treatment were chosen at random from those considered suitable for treatment. Storms not chosen for treatment were used as controls. During test periods, unseeded storms deepened slightly more than those seeded, and also yeilded slighty more rain (neither effect being statistically significant) (see Petterssen and others (1957)). 
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