On Tue, 13 Nov 2012 01:45:53 -0600, wrote:

What was the composition of that old cloth covered electrical wire?
Obviously some sort of cloth. What kind? Then what was added to it to
make it firm? From what I've seen it appears that some contained tar or
some sort of wax. But the white and red wires were painted, and I dont
think paint would adhere to wax. I'll take a wild guess and say that the
earlier stuff was not the same as the later. For example the early
knob and tube wire was thicker and seemed more tar-like, whereas the
later stuff found in BX was of a different consistency, with less
thickness.


Here's the Standard Handbook for Electrical Engineers - 1918 edition.
http://tinyurl.com/besodg3