11:35 a.m. on January 24, 2013 (EST)
Peter,
Certainly it is possible for sedimentary rocks to crack and even explode violently from heat great enough to cause trapped moisture to turn to steam. I don't disagree with that. However, stones have been warmed safely for thousands of years - unless sweat lodges, saunas, and baking stones are mythical - and still represent a safe means of heat storage and transfer. I would not think of heating a stone to the point that the stone was liable to burn me if I lay upon it - with a layer of insulation between body and stone. Most things that are useful have hidden dangers when used improperly - food, fire, etc. - yet we continue to use them for their benefits.
You said:
Again, it appears you have been misinformed. I refered to thermal imaging so you could find photos that would demonsrate the principles I was talking about. What they will show you is that when a person is standing, heat rises under the clothing, but gets lost as it vents out around the head. It's ALL about position.
No, it is not about position. If you remove the person's shirt or pants to the bare skin, the heat loss will be great there, whether the person is standing or lying down.
"Human skin is an almost perfect emitter of infrared radiation in the spectral region beyond 3 microns." from Thermography of the Human Body by Barnes, RB
Anywhere you have exposed skin, you are losing more heat than covered skin. No matter how the body is positioned, it makes the most sense to cover as much skin as possible to reduce heat loss. That is why I would cover my head and neck.
Now, if you want to read about heat loss through clothing, I suggest you start with this passage:
When a person is dressed with clothing, the process of
heat exchange between human body and the environment
becomes very complex. Heat and moisture transfer through
clothing are dissipated from the skin of human body. After
that, they are divided into two parts. One flows directly into
the environment by convection and radiation from the
exposed skin. The other is transferred into the clothing
microclimate. In the clothing microclimate, some is taken
away by ventilation, and the remainder goes through
clothing materials. Finally, it goes out from the outer surface
of clothing ensembles. In the clothing materials, conduction,
convection and radiation are the mechanisms of heat
transfer, while diffusion, absorption/desorption, condensation/
evaporation and wicking are the forms of liquid water/
moisture transfer. Heat and moisture transfer are coupled
since absorption/desorption and condensation/evaporation
are accompanied with heat release and absorption.
so that you can see the complexity of the subject and then you can wander into the math, which is way beyond me. see
A transient thermal model of the human body–clothing–environment system
Xianfu Wan, Jintu Fan
2007 Journal of Thermal Biology
Also, the thermal images you mention but do not point to, will, if the hands are not covered, also show the hands as bright as the face, though according to your reasoning, they should only be radiating heat in a particular position.
As for how much cold I have experienced; I am not going to enter into a puerile game of one-up-manship with you. Suffice that I spent winters in many Canadian provinces from Manitoba, east. I spent parts of some winters in tents when I was working in the woods or building a cabin for myself. I offered instances in which I had heated bricks to indicate the usefulness of the practice, not to fluff my chest hairs (of which I have four at last count).
I don't have a Tilley. I tried one, but looked silly in it - but not as foolish as you appear with your Freudian insufficiencies on display. (Of course, you will say "It is shrinkage from the cold." Yeah, right.)
Not meaning to pick on you, but when you're 'Talking through your ...... :)