Includes correspondence, manuscripts, books, pamphlets, articles, reviews, reports, notebooks, lecture notes, log books, financial documents, newspaper clippings, photographs, postcards, maps, diagrams and memorabilia concerning teaching at the State University of Iowa at Iowa City, 1864-1889, and St. Louis University, 1903-1907; scientific research in meteorology, astronomy, meteorites, physics, chemistry, crystallography, spectral analysis and molecular and atomic structure; weather observations and the Iowa Weather Service of which Hinrichs was founder and director, 1875-1888; Iowa geological survey and coal resources; participation in scientific conferences; legal proceedings as an expert witness in cases dealing with chloroform and phenacetine; European background, education and travels; public controversy surrounding the administrative reorganization of the State University of Iowa, 1885-1898, and his son Carl G. Hinrichs.