This is Ruhlman's response. He kicked over to Bob del Grosso. If you don't know this guy check him out on google. He has an awesome blog. The second email seems to support OG's heat sink theory-pretty cool I think!
From: "Robert del Grosso"
Date: May 8, 2009 5:49:35 AM EDT
To: "'Michael Ruhlman'"
Subject: RE: Troubling question re: thermal conductivity
Bones that are exposed at the tips of say a chicken leg heat more rapidly than muscle but bone that is surrounded by meat will not heat faster than the surrounding meat because it is buried within the meat. In other words it is insulated.
If you are talking about a rib roast the situation is a bit different. The bone still heats faster than the meat, but because the meat to bone ratio is so high (There is a hell of a lot of meat) the bone loses heat to the meat at a tremendous rate and so stays relatively cool.
From: Robert delGrosso
Date: May 8, 2009 7:59:32 AM EDT
To: Michael Ruhlman
Subject: bones and heat
I just remembered that another reason why meat next to the bone is more likely to be rare is that even though the bone heats faster than meat it also cools faster. And if the bone is cut at one end (as in a rib roast) it will act like a chimney and take the heat up and away even faster. b
When you come to a fork in the road, it's time to eat. www.AHungerArtist.bobdelgrosso.com