Although Schaefer had administrative duties as director of research, as well as overall director of the ASRC in later years, he still made as much time as possible for conducting his own research. In addition to experiments carried out in New York's Capital Region, he oversaw research at the Whiteface Mountain Field Station and Observatory as well as Flagstaff, Arizona, and led highly successful expeditions in the Yellowstone National Park. His fascination with particle studies continued during his ASRC years, leading to crucial investigations of carcinogens, acid rain, effects of particulate matter on global weather, aerosol studies, and much more. He also took great interest in alternative energy sources, solar energy specifically. Of course, cloud studies and ice-forming nuclei also remained a passion of Schaefer's. This subseries mainly consists of Schaefer's own investigations into those kinds of topics and offers a glimpse of his own notes, calculations, and observations on the subjects of interest to him.