"Some Other Guy" wrote

It's just a hell of a clever plumbing arrangement. Add heat at one part
(by burning gas, whatever), and another part gets cold:

http://www.gasrefrigerators.com/howitworks.htm

If that isn't the best explanation I have ever seen.... Good pictures, too.
;-)

I guess that turning the thing upside down got the hydrogen back up (down)
in the reservoir, so that it could keep in the evaporation side once the
heat got things moving. That makes sense, now. At the time, with no
internet in '83, it seemed a bit like magic, to me! g
--
Jim in NC