To that scheme it was essential that those celestial, atmospheric, or terrestrial phenomena that the public around him ascribed to the agency and purposes of the gods, should be understood as being produced by physical causes.

An eclipse, an earthquake, a storm, a shipwreck, unusual rain or drought, a good or a bad harvest--and not merely these, but many other occurrences far smaller and more unimportant, as we may see by the eighteenth chapter of the Characters of Theophrastus--were then regarded as visitations of the gods, requiring to be interpreted by recognized prophets, and to be appeased by ceremonial expiations.

When once a man became convinced that all these phenomena proceeded from physical agencies, a host of terrors and anxieties would disappear from the mind; and this Epicurus asserted to be the beneficent effect and real recommendation of physical philosophy.

He took little or no thought for scientific curiosity as a motive _per se_, which both Democritus and Aristotle put so much in the foreground.
Epicurus adopted the atomistic scheme of Democritus, but with some important variations.

He conceived that the atoms all moved with equal velocity in the downward direction of gravity.