Walter Hartley (1846-1913) was appointed professor of chemistry at the Royal College of Science for Ireland in 1879 and was dean of faculty at the time of the opening of the new building in 1911. A pioneer in the area of spectroscopy, Hartley was the recipient of many international honours. Among his most significant investigations are his work on the relationship between molecular structure and absorption spectra, and his discovery of the absorption of ultraviolet radiation by ozone. Many of his studies addressed practical applications of scientific research, covering subjects such as dyes for the Irish textile industry, studies for the brewing and distilling industries and chemicals for the prevention of potato blight.
Hartley was knighted in 1911. The conferral was to have taken place at the opening of the new college building, but he was unable to attend due to ill health. He retired that year for health reasons and died two years later. Hartley and his wife, the then popular novelist Mary (May) Laffan, had one son, Walter John, a former RCScI student who died at Gallipoli in 1915.