[ Gilles Chouinard asked in 150306 MMDigest, "Does anyone have
 [ a source for Chatterton's compound?"

Gilles,  Chatterton Compound was invented by John Chatterton around
1861.  It was also known as "laboratory wax."  You may be able to find
this reference:

  NAVY MIL-W-3172A CANC NOTICE 1 WAX, LABORATORY (CHATTERTON'S COMPOUND)

The product was available in several grades and was pretty much
considered obsolete for new applications during the late 1980's.
I have not seen it available for sale in over five years.

The ingredients of this product are, by weight, as follows: one part
of Stockholm tar, one part of rosin, and three parts of gutta-percha.
[Also described as] a mix of 1 part of Stockholm tar to 3 parts of
gutta-percha (greyish- black latex) and 1 part resin.  It forms a
plastic black insulating compound.

Many of the above names for the ingredients are the original and now
obsolete names.

Good luck,
Grant Chapman
West Point, New York