🚀 go-pugleaf

Nothing so strenuous as that is needed to freeze Hg; its m.p. is -39 C
(that's one of three ways you can tell that it's -40 out: the Hg
freezes in the thermometer, your spit crackles when it hits the
ground, and the F & C thermometers read the same).  The real question
is why the m.p. is so low.  I don't know.  The theory of the m.p. of
metals must be pretty subtle, since the kernel of an atom (i.e. the
atom minus its valence electrons) is spherical & can't notice when the
relative directions of its neighbors are disturbed.  I suspect it may
depend on non-nearest-neighbor interactions.

P.S.:  Also at -40 C (or F), deciduous trees are killed; north of
the -40 winter isotherm, the climax forests are evergreen.  I myself
have never experienced that temperature.
-- 
        Joe Fineman             jcf@world.std.com
        239 Clinton Road        (617) 731-9190
        Brookline, MA 02146