Figures, multiple induction machine and dust figures by William George Armstrong One detailed ink drawing showing a plan view of Armstrong's multiple induction machine. This is followed by 23 ink drawings, labelled figures I-XXII and figure V(A), showing 'dust figures' created in the disturbance of a small heap of chalk dust upon a plate of mica' by passing the arc flame of the multiple induction machine through it. These figures are described in detail in the accompanying paper. Subject: Physics / Scientific apparatus and instruments Prints of these figures were published in volume 52 of the Proceedings of the Royal Society alongside the paper 'On a multiple induction machine for producing high tension electricity, and on some remarkable results obtained with it'. 1892