§ 1. _The Diffusion of the Oak in Europe_—Jupiter the god of the oak,
the sky, and thunder; of these attributes the oak is probably primary
and the sky and thunder secondary; Europe covered with oak forests in
prehistoric times; remains of oaks found in peat-bogs; ancient lake
dwellings built on oaken piles; evidence of classical writers as to oak
forests in antiquity; oak-woods in modern Europe.
§ 2. _The Aryan God of the Oak and the Thunder_—Aryan worship of the oak
and of the god of the oak; Zeus as the god of the oak, the thunder, and
the rain in ancient Greece; Jupiter as the god of the oak, the thunder,
and the rain in ancient Italy; Celtic worship of the oak; Donar and Thor
the Teutonic gods of the oak and thunder; Perun the god of the oak and
thunder among the Slavs; Perkunas the god of the oak and thunder among
the Lithuanians; Taara the god of the oak and thunder among the
Esthonians; Parjanya, the old Indian god of thunder, rain, and
fertility; gods of thunder and rain in America, Africa, and the
Caucasus; traces of the worship of the oak in modern Europe; in the
great European god of the oak, the thunder, and the rain, the original
element seems to have been the oak.