Source: National Science Foundation
Through ancient and modern times many methods have been proposed and attempted to induce or to aid rainfall. Two U. S. Government patents on methods of rainmaking were issued before the turn of the 20th century based, respectively, upon the production of carbon dioxide by expending "liquified carbonic acid gas" and upon concussion by the detonation of explosives. Interestingly enough the long since expired patent, based on the production of carbon dioxide in the form of dry ice, anticipated the cloud seeders of today. The pioneering field and laboratory work of meteorologists in the War and Navy Departments on the popular notion 1 that rainfall could be caused by the
detonation of explosives was supported by Federal Government funds. Even social, political and legal conflicts over weather and climate modification are not new. In 1916 San Diego's employment of a rainmaker, resulting in claims of loss of life and property damage of a million dollars, anticipated by half a century the litigation and State and local legislative action of today.
The 1946 demonstration that clouds might be modified and rain produced by scientific methods arose out of the World War II investigations of fog particles by Langmuir and Schaefer. The military possibilities of this discovery led the armed services to support a broad theoretical, laboratory and field program in cloud modification from 1947 to 1952, known as Project Cirrus. Civilian and military implications were investigated by the
Cloud Physics Project of the U.S. Weather Bureau, Air Force and National Advisory Committee for Aeronautics from 1948 to 1951. The military services followed the termination of Project Cirrus in 1952 with a Department of Defense 5 year Artificial Cloud Nucleation Project.