In a search for clues to the nature of aerosol scavenging and precipitation formation processes in convective storms, daily rain samples were collected in networks of 80 or 85 open polyethylene containers near St. Louis during the summers of 1972--1975. Collected samples were filtered to separate soluble and insoluble materials, and both fractions were analyzed for a variety of constituents, including Li, Na, Mg, K, Ca, Fe, Zn, Cd, Pb, and SO4=. To investigate which element/solubility fractions had similar deposition patterns and how those patterns related to each other and to rainfall, individual storms were analyzed by factor analysis. The results showed that deposition patterns grouped consistently into four main types: (1) soluble soil elements, (2) insoluble soil elements, (3) soluble pollutant elements, and (4) insoluble pollutant elements. Differences between the deposition patterns of pollutants and soil elements may be accounted for by the distribution of sources, but differences betwen soluble and insoluble portions of the same element probably reflect important differences in scavenging and/or precipitation formation processes. These processes may be amenable to further investigation using techniques similar to those described in this paper.