Born at Le Bugue, he studied Medicine
at Montpellier, graduating in 1609. We know hardly anything of his
life or his professional activities, even though they were held in
high regard by his contemporaries.
In 1630, Rey published the work which gave
him his place in the history of chemistry. In the Essays on the
cause of the increase in weight of tin and lead when they calcinate,
the French doctor explained the greater weight of two materials (tin
and lead) when they are heated. Rey attributed the phenomenon to the
"weight" of air - rendered in turn more dense, heavy and, to some
extent, sticky by the prolonged action of heating - which joined itself
to the natural weight of lead and tin.
Rey's research, in addition to heralding
Lavoisier's conclusions on the crucial role of air in the process
of calcination, confirmed the thesis of the weight of air, on an axis
closer to chemical investigation, which was fundamental for the development
of the modern barometer a decade later.