Science: Rainmaking with Soot?

Most clouds and fogs are made of water droplets that are too small to fall. Nature has various methods of making the droplets grow big enough to fall as rain, but they are not always in operation. Often great clouds heavy with water float across a thirsty land without dropping rain, or fog hangs for hours over an airport.

The well-known silver iodide and Dry Ice methods of cloud precipitation work only on clouds that are well below freezing. Warm clouds are common,too. and Dr. Florence W. van Straten of the Naval Weather Service...