Sub-series 4. Research and Development Files, 1892-1926, undated

Arranged alphabetically by subject, this sub-series contains research and development files collected and maintained by the Dearborn Chemical Company. A majority of the materials in this sub-series concern water treatment formulas developed by Dearborn Chemical Company and its corporate predecessor Dearborn Drug and Chemical Works. A small amount of materials regarding Dearborn Drug and Chemical Works' analysis of a handful of products manufactured by its competitors are also present. A small amount of materials regarding drug formulas developed by Winthrop Drug & Chemical Company, a pharmaceuticals firm of which Dearborn co-founder William H. Edgar was president, are also preserved here.

Water treatment formula books make up the majority of the materials in the Research and Development Files. A few water treatment analysis reports and drug formulas are also present in this sub-series. A small amount of accompanying notes and correspondence are preserved in this sub-series as well.