Figures, experimental equipment by J J [Joseph John] Thomson and R [Richard] Threlfall Four figures in black ink, labelled figures 1-4, showing a series of vessels and tubes used by Thomson and Threlfall in their investigations into an effect produced by the passage of an electric discharge through pure nitrogen. Subject: Chemistry / Physics / Electricity These figures were published in volume 40 of the Proceedings of the Royal Society alongside the paper 'On an effect produced by the passage of an electric discharge through pure nitrogen'. 1886