Re: [Phys-l] Temperture profile in a graviational field

[brian whatcott <betwys1@sbcglobal.net>]

On 1/17/2012 5:43 PM, John Denker wrote:
> On 01/17/2012 03:46 PM, Christopher M. Gould wrote:
> > mass transport equilibrium .... Here, with an imposed
> > gravitational potential, air at the top of a column will be colder than
> > at the bottom.
> <hypothesis>
>    Let's explore that idea.
>
>    To make it more interesting, set up a copper rod next to the
>    air column.  There will be no mass transport in the copper,
>    just thermal conductivity, so it will be isothermal.
>
>    The rod and the air column have the same temperature at the
>    bottom, since they are both in contact with the heat bath
>    at that point.
>
>    If they have a different temperature at the top, you can
>    run a heat engine using the difference.  Voilà!  Perpetual
>    motion machine.
> </hypothesis>
Ah, yes: not accomplished on vertical air masses (as far as I know) ,
 but certainly done on vertical sea masses.
 Not a mobile perp., however, just a heat engine of the ordinary kind.

Brian W