[ Ref 100124 MMDigest, Aeolian Free-Reed Clarinet Pipes

Chatterton's compound was developed as an insulating material for
undersea telegraph cables in 1858 by cable engineer Willoughby Smith.
John Chatterton, manager of the India Rubber, Gutta Percha & Telegrah
Works Company in London, patented a method of applying the compound to
the cables in 1859, and his name became attached to the substance.

The compound "is composed of certain proportions of Stockholm tar,
resin, and gutta percha".  While the main insulation of the cables
was pure gutta percha (the sap of a tree found only in Malaysia),
Chatterton's compound was used to fill gaps between the copper wires
of the cable and to improve adhesion of the layers of gutta percha
surrounding the copper conductor.

Details from "Submarine Telegraphs" by Charles Bright, published in 1898.

Gutta percha was the first thermoplastic material ever developed, and
its close relative, Chatterton's compound, was presumably found early
on by the reed tuners to be the best substance for their needs.

American readers will find the entire text of Bright's book available at
Google Books:

http://books.google.com/books?id=5iZ_AAAAMAAJ&pg=PA315&dq=%22chatterton's+compound%22&num=100&as_brr=1&ei=-EJmS7m_FZ6-zgTsoJ3aCg&client=opera&cd=5#v=onepage&q=%22chatterton's%20compound%22&f=false 

Bill Burns
Long Island, New York, USA
http://atlantic-cable.com/