to these the Arabic _nefs_ and _ruh_ correspond. The same is
the history of the Sanskrit atman and prana, of Greek _psyche_
and _pneuma_, of Latin _anima, animus, spiritus_. So Slavonic
_duch_ has developed the meaning of 'breath' into that of 'soul'
or 'spirit'; and the dialects of the gypsies have this word _duk_
with the meanings of 'breath, spirit, ghost,' whether these
pariahs brought the word from India as part of their inheritance
of Aryan speech, or whether they adopted it in their migration
across Slavonic lands. German _geist_ and English _ghost_,
too, may possibly have the same original sense of breath." How
marvellously significant this ascent from the perceptions of
wind and breath to what we now understand by soul and spirit!
The most attenuated concepts have their basis in the physical
world. Even to this present day, as Max Müller remarks, "the
soul or the spirit remains a breath, an airy breath, for this is the
least material image of the soul which they can conceive."

Another doctrine of Anaximenes is most worthy of note by
nature mystics, as well as by scientists. It is well stated by
Theophrastus. "The air differs in rarity and in density as the
nature of things is different; when very attenuated it becomes
fire, when more condensed, wind, and then cloud; and when
still more condensed, water and earth and stone; and all other
things are composed of these; and he regards motion as eternal,
and by this changes are produced." We have here a distinct
adumbration of the atomic theory in its most defensible form--
that is to say, a conception which makes the differences in
various substances consist in differences in condensation or
rarefaction of the particles of the primary substance. The simple
normal condition of this substance he deemed to be air. In its