Samples of precipitation from 31 storms were collected from October 1986 through December 1987 at a site near Quabbin Reservoir in central Massachusetts and were analyzed for pH, specific conductance, and concentrations of common chemical constituent. Twenty-four storms followed a conti- nental path west of the Appalachian Mountains. The remaining seven storms followed a coastal path east of the Appalachian Mountains along the Atlantic Coast. Precipitation from the continental storms was more acidic than precipitation from the coastal storms according to a nonparametric statistical com- parison. Because the continental storms had less volume, the loads of hydrogen ions and other common chemical constituents from both groups were not statistically different. The variability of within- storm precipitation chemistry was evaluated for 8 of the 31 storms. Seven of the storms showed evidence of suspended-particulate removal at levels between the cloud layer and the land surface during their early stages. The remaining storm, also the most acidic, showed evidence of suspended- particulate removal within the cloud layer as indicated by a relatively constant pH throughout the storm. Surface-air concentrations of sulfur dioxide and nitrogen dioxide before, during, and after each of the eight storms were compared to within-storm values of pH and precipitation. Seven of the storms were accompanied by decreased atmospheric concen- trations of both sulfur dioxide and nitrogen dioxide in the early stages of the storm. For three of the storms, atmospheric concentrations of sulfur dioxide and nitrogen dioxide were higher during the 24-hour period after the storm than the 24-hour period pre- ceding the storm. Particulates in precipitation samples were analyzed for three storms. Biotite was the predominant mineral in two of the storms. Other minerals detected were garnet, quartz, gypsum, hematite, epidote, ilmenite, eggonite, halite, rutile, and organic ash.