Here are quotes from James Clerk Maxwell's A Treatise on Electricity and Magnetism where he conjectures on the existence of a medium underlying electromagnetic phenomena - Is the medium the source of electromagnetic phenomena? Then what is this medium composed of? If it is composed of electromagnetic waves then that must mean that electricity is present in all points of space. If this electricity is present everywhere then it can be tapped. Articles 865-866. This book can be read on-line and downloaded in pdf form free from Google Books:
A Treatise on Electricity and Magnetism by James Clerk Maxwell, M.A.
LL.D. Edin., D.C.L., F.R.SS. London and Edinburgh
Honorary Fellow of Trinity College, and Professor of Experimental Physics in the University of Cambridge
Volume II, Second edition.
Oxford at the Clarendon Press, 1881
