image pp_52_16_15
Image number: RS.11606
Credit: ©The Royal Society

Spark discharge figure



Object type



height (drawing): 113mm
width (drawing): 101mm



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.13 was produced without any visible discharge across the dust plate. The same battery was used as in the last and several preceding cases, but the Leyden jars were allowed to leak sufficiently to prevent their reaching the sparking point’.

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 13 plate 9 in the published paper.

The image is inscribed below in ink: ‘No.XIII’ and ‘2/3’. 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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