this, as in all his
life-work, he showed himself to be a most remarkable man. Davy said of
him, a generation later, that no other person ever discovered so many
new and curious substances as he; yet to the last he was only an amateur
in science, his profession, as we know, being the ministry. There is
hardly another case in history of a man not a specialist in science
accomplishing so much in original research as did this chemist,
physiologist, electrician; the mathematician, logician, and moralist;
the theologian, mental philosopher, and political economist. He took
all knowledge for his field; but how he found time for his numberless
researches and multifarious writings, along with his every-day duties,
must ever remain a mystery to ordinary mortals.

That this marvellously receptive, flexible mind should have refused
acceptance to the clearly logical doctrines of the new chemistry seems
equally inexplicable. But so it was. To the very last, after all his
friends had capitulated, Priestley kept up the fight. From America he
sent out his last defy to the enemy, in 1800, in a brochure entitled
"The Doctrine of Phlogiston Upheld," etc. In the mind of its author it
was little less than a paean of victory; but all the world beside knew
that it was the swan-song of the doctrine of phlogiston. Despite the
defiance of this single warrior the battle was really lost and won,
and as the century closed "antiphlogistic" chemistry had practical
possession of the field.

III. CHEMISTRY SINCE THE TIME OF DALTON

JOHN DALTON AND THE ATOMIC THEORY

Small beginnings as have great endings--sometimes. As a case in
point, note what came of the small, original effort of a self-trained
back-country Quaker youth named John Dalton, who along towards the close
of the eighteenth century became interested in the weather, and was
led to construct and use a crude water-gauge to test the amount of the
rainfall. The simple experiments thus inaugurated led to no fewer than
two hundred thousand recorded observations regarding the weather,
which formed the basis for some of the most epochal discoveries in
meteorology, as we have seen. But this was only a beginning. The simple
rain-gauge pointed the way to the most important generalization of
the nineteenth century in a field of science with which, to the casual
observer, it might seem to have no alliance whatever. The wonderful
theory of atoms, on which the whole gigantic structure of modern