image pp_52_16_21
Image number: RS.11612
Credit: ©The Royal Society

Spark discharge figure



Object type



height (drawing): 135mm
width (drawing): 124mm



Diagram created by sparking from Lord Armstrong’s machine for producing high tension electricity. These patterns were made in a powder of magnesium oxide (‘calcined magnesia’) and carbon black. The images were then photographed and drawings produced from them.

The author states in his paper that: ‘No.19 shows the effect of inverting two wine glasses upon the dust plate so as to cover two circular patches of the dust and protect them from the action of the air…’

Illustration from the manuscript version of the paper ‘On a multiple induction machine for producing high tension electricity, and on some remarkable results obtained with it’, by Lord Armstrong, Proceedings of the Royal Society, vol.52 (1892), pp.176-191. Printed as figure 19 plate 12 in the published paper.

The image is inscribed below in ink: ‘No.XIX’ and ‘4/7’. Imprint details verso.

William George Armstrong, Baron Armstrong (1810-1900) armaments manufacturer and industrialist was elected a Fellow of the Royal Society in 1846.

Associated place

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