Close-up view of raw material and machinery used in the manufacture of water treatment chemicals at the Dearborn Chemical Company's 35th Street laboratory facility and manufacturing plant. Founded in 1887, the Dearborn…

Close-up view of scientific apparatus used at the Dearborn Chemical Company 35th Street laboratory facilities located in Chicago, Illinois. Founded in 1887, the Dearborn Chemical Company was a corporate ancestor of…

General view of a storage tank in use at the Dearborn Chemical Company's 35th Street laboratory facility and manufacturing plant. The employee visible in the photograph is unidentified. Founded in 1887, the Dearborn…

General view of employee Ted Slisz at work in the Dearborn Chemical Company's 35th Street Laboratory facility and manufacturing plant. An assortment of beakers is visible on the work bench. Founded in 1887, the Dearborn…

General view of employee Ted Slisz using a balance at the Dearborn Chemical Company's 35th Street Laboratory facility and manufacturing plant. Founded in 1887, the Dearborn Chemical Company was a corporate ancestor of…

General view of employee Al Slisg conducting a water analysis test at the Dearborn Chemical Company's 35th Street laboratory and manufacturing facility located in Chicago, Illinois. Founded in 1887, the Dearborn…

General view of employee C.M. Hoffman seated in his office at the Dearborn Chemical Company's 35th Street laboratory facility and manufacturing plant. Founded in 1887, the Dearborn Chemical Company was a corporate…

Close-up view of employee C.M. Hoffman seated at a desk at the Dearborn Chemical Company's 35th Street laboratory facility and manufacturing plant. Founded in 1887, the Dearborn Chemical Company was a corporate ancestor…

General view of employee Dudley Kimball French at work in the offices at the Dearborn Chemical Company's 35th Street laboratory facility and manufacturing plant. Founded in 1887, the Dearborn Chemical Company was a…

Close-up view of employee E.M. Converse seated in his office at the Dearborn Chemical Company's 35th Street laboratory facility and manufacturing plant. Founded in 1887, the Dearborn Chemical Company was a corporate…

Close-up view of employee E.M. Converse seated in his office at the Dearborn Chemical Company's 35th Street laboratory facility and manufacturing plant. Founded in 1887, the Dearborn Chemical Company was a corporate…

General view of male and female employees at work in an office space at the Dearborn Chemical Company 35th Street laboratory facilities located in Chicago, Illinois. While the majority of the employees are unidentified,…

General view of male and female employees at work in an office space at the Dearborn Chemical Company 35th Street laboratory facilities located in Chicago, Illinois. While the two female employees closest to the camera…

General view of employees at work in an office at the Dearborn Chemical Company's 35th Street laboratory facility and manufacturing plant. The employees seated at the desks are identified as John W. Brashears (left) and…

General view of male and female employees at work at the Dearborn Chemical Company's 35th Street laboratory facility and manufacturing plant. Founded in 1887, the Dearborn Chemical Company was a corporate ancestor of…

General view of male and female employees at work at the Dearborn Chemical Company's 35th Street laboratory facility and manufacturing plant. Founded in 1887, the Dearborn Chemical Company was a corporate ancestor of…

General view of Eva Vaughn (left) and an unidentified employee at work in an office space at the Dearborn Chemical Company 35th Street laboratory facilities located in Chicago, Illinois. Founded in 1887, the Dearborn…

General view of female employees at work at the Dearborn Chemical Company's 35th Street laboratory facility and manufacturing plant. Founded in 1887, the Dearborn Chemical Company was a corporate ancestor of…

General view of female employees at work at the Dearborn Chemical Company's 35th Street laboratory facility and manufacturing plant. Founded in 1887, the Dearborn Chemical Company was a corporate ancestor of…

Close-up view of employee Fred L. Baker seated in his office at the Dearborn Chemical Company's 35th Street laboratory facility and manufacturing plant. Founded in 1887, the Dearborn Chemical Company was a corporate…

Close-up view of employee George R. Carr seated in his office at the Dearborn Chemical Company's 35th Street laboratory facility and manufacturing plant. Founded in 1887, the Dearborn Chemical Company was a corporate…

General view of the information desk at the Dearborn Chemical Company's 35th Street laboratory facility and manufacturing plant. The employees visible in the photograph are identified as J. Beckerley (seated) and C.M.…

Close-up view of employee J.D. Purcell seated in his office at the Dearborn Chemical Company's 35th Street laboratory facility and manufacturing plant. Founded in 1887, the Dearborn Chemical Company was a corporate…

Close-up view of employee J.W. Harkins seated at his desk at the Dearborn Chemical Company's 35th Street laboratory facility and manufacturing plant. Founded in 1887, the Dearborn Chemical Company was a corporate…

General view of the laboratory office space at the Dearborn Chemical Company 35th Street laboratory facilities located in Chicago, Illinois. The employees seated at the desks are identified as A.H. Reynolds (left) and…