Two documents, both of which concern illumination studies, are presented. The first is a report on the illumination study at Hawthorne, which began Nov. 24, 1924 and ended April 30, 1927. In this study, candles of various lengths were introduced...
Correspondence passed among investigators from September 1928 to February 1934. Letters to G.A. Pennock from Dr. Elton Mayo examined blood pressure, visits, generalizing mind for administration and societal changes; biological measures needs,...