Laplacian Sigils – William George Armstrong’s Electrical Discharge Experiments 
Friday, 5 December 2014
William George Armstrong Electrical Discharge Experiments 
The colour prints created by The Autotype Company to accompany William George Armstrong’s lectures and papers in the late 1800’s are probably some of the earliest electrical discharge visualisations created and widely disseminated. Their earthy colours and explosive textures are the result of applying an electrostatic discharge to a plate dusted with lead and sulphur. In this literal alchemical transaction, materials are transformed into delicately fine Laplacian aggregations known as Lichtenberg figures. The images were tellingly annotated by Armstrong in a paper presented at the Royal Society in 1899:
‘I have already spoken of electricity as organised motion, and we have here an example of it carried apparently to the verge of life […] we see arborescent forms, showing trees and undergrowth, in which stems, branches, and leaves find their approximate representatives […] even the root is indicated lying at the foot of the stem’
Fittingly, Armstrong used two materials strongly associated with alchemical practice and symbolism. So these fractal figures might be seen as sigils of a real elemental transmutation of fire, earth and metal governed by a process of self-organisation. In the computational realm electrical discharge patterns can be accurately modelled by applying stochastic procedures to Diffusion Limited Aggregation and Laplacian Growth algorithms.
Images discovered at: Prints.royalsociety.org