more intense. For when the Big Bertha had shot its bolt, that was the
end of it. Whomever it hit was hurt, but after that the steel fragments
of the shell lay on the ground harmless and inert. The men in the
dugouts could hear the shells whistle overhead without alarm. But the
poison gas could penetrate where the rifle ball could not. The malignant
molecules seemed to search out their victims. They crept through the
crevices of the subterranean shelters. They hunted for the pinholes in
the face masks. They lay in wait for days in the trenches for the
soldiers' return as a cat watches at the hole of a mouse. The cannon
ball could be seen and heard. The poison gas was invisible and
inaudible, and sometimes even the chemical sense which nature has given
man for his protection, the sense of smell, failed to give warning of
the approach of the foe.

The smaller the matter that man can deal with the more he can get out of
it. So long as man was dependent for power upon wind and water his
working capacity was very limited. But as soon as he passed over the
border line from physics into chemistry and learned how to use the
molecule, his efficiency in work and warfare was multiplied manifold.
The molecular bombardment of the piston by steam or the gases of
combustion runs his engines and propels his cars. The first man who
wanted to kill another from a safe distance threw the stone by his arm's
strength. David added to his arm the centrifugal force of a sling when
he slew Goliath. The Romans improved on this by concentrating in a
catapult the strength of a score of slaves and casting stone cannon
balls to the top of the city wall. But finally man got closer to
nature's secret and discovered that by loosing a swarm of gaseous
molecules he could throw his projectile seventy-five miles and then by
the same force burst it into flying fragments. There is no smaller
projectile than the atom unless our belligerent chemists can find a way