When I read this I wondered if the material Murdock invented was related to what we now call Bois Durci, or something similar to it (Murdock died before Bois Durci was invented in 1855). Bois Durci is "a process of taking sawdust, albumen or animal blood and hardening in a mould to form the desired object.... Various medals and medallions were made this way after being introduced at the 1862 London Exhibition of the Works of Industry of All Nations." (see the earlier E-Sylum articles on Bois Durci).

Is anyone aware of surviving medals made by Murdoch's peat moss process? Murdock was a contemporary of Boulton and Watt in London. Below is a photo from Wikipedia of a bronze statue of the three in in Birmingham, England.

To read the complete passage, see:Men of invention and industry, Google Books

To read earlier E-Sylum articles on Bois Durci, see:BOOK REVEW: BOIS DURCI, A NATURAL PLASTIC 1855-1927, BY GASTON VERMOSEN(www.coinbooks.org/esylum_v11n36a04.html)
MORE ON BOIS DURCI(www.coinbooks.org/esylum_v11n37a09.html)