Nick Maclaren wrote:
Chris Bacon writes:
| White. More importantly, it should be porous to water vapour, as
| sweating is the primary mechanism for keeping the brain cool.
|
| But it's not simply perspiration from the scalp that cools
| the head, is it. Leaving one ankle, wrist or whatnot(!)
| uncovered would do just the same job.

No, it wouldn't. The human brain is such a heat source, and so sensitive
to overheating, that there is a lot of specialist blood flow to the
scalp and even through the skull. You remark applies to the rest of
the body, but only partially to the head.

So if you wear an impermeable lagged membrane over that part
of your head your brain will "overheat"? I don't think so.