US geologist, mining engineer, and mountaineer Clarence King was the 1st director of the US Geological Survey. While preparing his report, Systematic Geology, he found the first US glaciers. Mostly known for his exploration of the Sierra Nevada mountain range, he penned the iconic work Mountaineering in the Sierra Nevada.
Merrill Wallace Chase was an American immunologist best remembered for discovering cell-mediated immunology. He discovered that white blood cells were important agents of the immune system. Merrill Wallace ChaCse's discoveries laid the foundation for later research that identified the role of T cells, B cells, and other kinds of white blood cells.
Apart from leading the Dudley Observatory as its director and working for the American govenment, astronomer Lewis Boss had also created some of the most significant catalogs on stars and even corrected existing errors in previous catalogs. The crater Boss on the Moon was named in his honor.