A Hundred Years of Chemistry I is a short essay by Frank Wigglesworth Clarke. Frank Wigglesworth Clarke (March 19, 1847 - May 23, 1931) of Boston, Massachusetts, and Washington, D.C. was an American scientist and chemist. Sometimes known as the "Father of Geochemistry," Clarke is credited with determining the composition of the Earth's crust. He was a founder of The American Chemical Society and served as its President, 1901. Professor Clarke was the first theorist to advance a hypothesis regarding the evolution of elements. This concept emerged early in his intellectual career. His "Evolution and the Spectroscope" (1873) appear in Popular Science Monthly. It noted a parallel evolution of minerals, accompanying that of plant life. He was known for pushing mineral analysis beyond analytical results. He sought compilations of the associations, alterations, and syntheses of each mineral sample. His study Constants of Nature (Smithsonian Institution 1876) was one of the first collections of both physical and chemical constants. The USGS's Atomic Weights series became standard references for the chemistry and geochemistry professions and academic fields. Clarke was also an academic collaborator. His Data on Geochemistry became a means of collecting peer professional efforts for common use across five successive editions. Beginning with his Constitution of silicates (1895), Professor Clarke advanced a methodology of geochemical analysis which described a mineral's composition through fact coordination. Priority was placed on contextualizing the research by describing constitution, structure and relationship with other minerals. The mineral sample's natural history was the end goal, a means of articulating the mineral's alteration products and pseudomorphs as a record of chemical change. To this record Clarke added the artificial history record available in the laboratory. The natural and artificial histories, combined, created what Clarke called the "constitution of a mineral." The constitution of a mineral was best summarized by, in the words of Clarke, "a good formula" which " . . . indicates the convergence of knowledge; if it fulfills that purpose it is useful, even though it may be supplanted at some later day by an expression of still greater generality." Clarke authored one of the first governmental reports on the teaching of science in the United States. The report was sponsored by the US Commissioner of Education in 1878 and titled: "Report on the teaching of chemistry and physics in the United States." It was printed by the Government Printing Office in Washington, DC. Clarke's stated purpose in writing the report was to "state the facts, and secondly, to point out defects and remedies--to show on the one hand what is, and on the other what ought to be" (p. 377) relative to the teaching of chemistry and physics in the United States. The report was exhaustive, spanning secondary institutions, normal schools, and more than 350 colleges and universities. In 1908 the first edition of Clarke's work, The Data of Geochemistry (Survey Bulletin no. 330), was published while he was the Chief Chemist at the U.S. Geological Survey. Clarke's fifth edition of this bulletin was released in 1924; the year he retired. Professor Clarke was also an early pioneer (1891) of work efficiency studies, using the theory of probability and least squares as the basis for work review.