Bob Gardner wrote:

Gotta admit that I am working from memory of events many long years ago and
may easily have screwed up the details. With regard to the fog, however,
there has to be moisture from somewhere...simple expansion is not the whole
story. Fog is, after all, a gazillion eensy-teensy droplets.

When the pressure drops, the temperature drops. All that happened was you went
below the dew point in the chamber.

George Patterson
Great discoveries are not announced with "Eureka!". What's usually said is
"Hummmmm... That's interesting...."