Research required to make cloud seeding a quantitative science

An approach to putting practical cloud seeding on a valid engineering basis is described. The main problem is the development of precipitation graphs from which is possible to (1) compare the difference in rainfall resulting from differing concentrations of freezing nuclei, (2) determine the optimum seeding concentration for the class of cloud in question, and (3) determine the cloud seeding potentialities of a given watershed from previously obtained data, by observational and computational procedures. Planning procedures and theorems are described. Examples of graphs are exhibited showing the theoretical time of precipitation initiation when the initiation is by the warm cloud condensation coalescence process or the ice crystal process.