Wallace,
That was an obscure reference, I admit! 
Here is the link to the @f_pal topic:
Recumbent bike with motorized gas trailer - Projects - Drive On Wood!
I am working on the article he linked to in post #4, The link does not work and I found it the hard way. Article is in French, I am working on translating because it is interesting. To cut to the chase, carbonite is ball-shaped compressed chunks of coal dust and powdered pitch (wood tar) as a binder. I am better at finding translating tools now. Soon a text file…Here is a preview… 
Click on the jpeg screen shot and it will clear up a bit.
