image pp_52_16_19
Image number: RS.11610
Credit: ©The Royal Society

Spark discharge figure



Object type



height (drawing): 133mm
width (drawing): 126mm



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.17 shows similar effects [to No.16] produced by heavier discharges on a more thickly covered dust plate…’.

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 17 plate 11 in the published paper.

The image is inscribed below in ink: ‘No.XVII’ 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.

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