On the 10th of June 1875 he died in Dalton, Georgia, a city which in 1848 he had helped to found.
The "symbols" for the elements used by Dalton, apparently suggested by those of the alchemists, have been rejected in favour of those which were introduced by Berzelius.
Dalton believed that the molecules of the elementary gases consisted each of one atom; his diagram for hydrogen gas makes the point clear.
Dalton, who was a mathematical physicist even more than a chemist, had given much thought to the study of gases.
The Aristotelian would find no difficulty in such a variability; it is only the disciple of Dalton to whom it seems impossible.