Diagrams, experimental equipment by W H [William Henry] Preece Two diagrams, labelled figures 1-2, showing a schematic of the setup of Preece's lamp facing a white screen and a circuit diagram for the same. Subject: Optics Prints of these diagrams were published in volume 36 of the Proceedings of the Royal Society alongside the paper 'On a new standard of illumination and the measurement of light'. 1883