I found it in the Dry Kiln Operator's Manual shortly after I first posted the question. By the way, chapter 1, page 37.
Varies quite a bit from something I had found online from another source.
Manual says tangental 4.5; another online source 6.6
Manual says radial 2.5; another online source 3.7
Manual says specific gravity 0.42; another online source says 0.55