Diagram, experimental observation by [George Downing] Liveing and [James] Dewar A diagram of an observation made using a diffraction grating during Liveing and Dewar's investigation into the reversal of hydrogen lines. Subject: Physics A print of this diagram was published in volume 35 of the Proceedings of the Royal Society alongside the paper 'Note on the reversal of hydrogen lines; and on the outburst of hydrogen lines when water is dropped into the arc'. 1883