on this plan, well-defined shadows
*
Fig. 10
(cropped from border; squared)
illustrating Silvanus P. Thompson (1851-1916 *), “Electric Shadows and Luminescence.” Proceedings of the Royal Institution of Great Britain / Abstracts of the Discourses Delivered at the Evening Meetings 15 (May 8, 1896) : 191-216
Mayo Clinic / Stanford copy (no date of digitization)
‐
“...it might be possible to produce electric shadows without having resort to any photography. You are aware that if the surface or any part of the surface of a body is electrified, the fact that it is electrified can be ascertained by dusting over it mixed powders of red lead and sulphur (or red lead and lycopodium)... I have succeeded in producing, on this plan, well-defined shadows which will now be demonstrated to you... Fig. 10 is a shadow taken in this way...”
207-209
tags:
method; tools; xerography; proto-xerography; S. P. Thompson, “Electric Shadows and Luminescence” (1896)