ca. 1968. On photo verso: "Any electrical power requirement for experiments of the type being carried out in this physics laboratory can be obtained from a central switchboard. trunk lines leading to each laboratory can carry AC or DC with voltage, amperage and other factors carefully controlled. Work tables in the labs can be moved to any desired location and plugged into floor or wall outlets fed by the desired trunk line. Water, natural gas and air are also supplied via similar centralized systems."