Weather Modification History
Scope of Prior Art
“There appears to be little doubt that the invention of Weathercord by Mr. Merryweather was a significant milestone in the development of cloud seeding nuclei generators. Although the carrying of burner generators of silver iodide by aircraft had been tried, the search for an efficient method of introducing an appropriate amount of nuclei into clouds continued. The ineffectiveness of burner generators was commented upon at 211 of the Goyer, et al., article:
For several years burner generators have been flown through clouds in an effort to insure that the nuclei are introduced into the clouds. Although a step in the right direction, this operation does not ensure that a sufficiently high concentration of nuclei is injected into the cloud. Considering the speed of a seeding aircraft carrying burner generators, the concentration of nuclei per unit volume is very low.
The article, in comparing the increased effectiveness expected from the use of Weathercord as a nucleating generator over the more conventional burner generators, states at 212:
Burner generators may finally inject into clouds as large a concentration of nuclei as pyrotechnics or Weathercord but over such a long time duration that the effect of the latent heat is so diluted by heat transfer mechanisms, that it becomes negligible. It is reasonable to believe that the apparent differences in results between the two seeding methods rest not only on the total number of nuclei introduced into clouds but on the release of latent heat of crystallization per unit volume and unit time. In this respect both pyrotechnics and Weathercord should be orders of magnitude more effective than burner generators.”