atomical
/əˈtɒmɪkl/adjective
1Of the nature of an atom or atoms; consisting of or involving atoms. Compare atomic. Now rare.
2Chiefly History of Science. Designating or adhering to the doctrine of atoms as understood in ancient Greek philosophy or later.
Origin
Early 17th century; earliest use found in Edmund Bolton (?1575/5–?1634), antiquary and historian. From atom + -ical.