In the 1850 and '60s, John Chatterton was manager of the engineering
department of the Gutta Percha Company in London.  This company
supplied the "core" -- a multi-strand copper conductor insulated
with gutta percha -- which was the basis of undersea telegraph cables,
a major industry of the time.  His additions to pure gutta percha to
form Chatterton's compound were intended to provide a more compliant
coating to smooth out irregularities between the copper wires and the
gutta percha, and between multiple coatings of gutta percha.  Here's
the page on the company on my history website:

  http://atlantic-cable.com/Article/GuttaPercha/ 

Chatterton's patent on the compound was issued in 1858, GB Patent
number 1811 of that year.  Chatterton's compound was also used for
other applications, such as attaching the weights to reed tongues in
reed organ, and I believe organ restorers still use it today.

For anyone wanting to experiment with home-brewed compounds, gutta
percha itself is used in dentistry and can be obtained from dental
supply houses, although you might have to enlist the help of a dentist
to get these businesses to deal with you.  On checking the MMD Archives,
I see there have been several discussion on this subject in the past.

Bill Burns